Add support for Sparse QR factorization

This commit is contained in:
Desire NUENTSA
2012-11-12 15:20:37 +01:00
parent 474716ec5b
commit 9cf77ce1d8
23 changed files with 6449 additions and 2 deletions

View File

@@ -18,6 +18,13 @@ single.cpp double.cpp complex_single.cpp complex_double.cpp ../blas/xerbla.cpp
if(EIGEN_Fortran_COMPILER_WORKS)
set(EigenLapack_SRCS
slarft.f dlarft.f clarft.f zlarft.f
slarfb.f dlarfb.f clarfb.f zlarfb.f
slarfg.f dlarfg.f clarfg.f zlarfg.f
slarf.f dlarf.f clarf.f zlarf.f
)
get_filename_component(eigen_full_path_to_reference_to_reference_lapack "./reference/" ABSOLUTE)
if(EXISTS ${eigen_full_path_to_reference_to_reference_lapack})
set(EigenLapack_SRCS ${EigenLapack_SRCS}
@@ -26,7 +33,6 @@ set(EigenLapack_SRCS ${EigenLapack_SRCS}
# reference/dgetrf.f reference/cgetrf.f reference/sgetrf.f reference/zgetrf.f
# reference/cgetrs.f reference/dgetrs.f reference/sgetrs.f reference/zgetrs.f
# reference/dsyev.f reference/ssyev.f
reference/dlamch.f reference/ilaver.f reference/lsame.f reference/slamch.f reference/second_NONE.f reference/dsecnd_NONE.f
reference/cbdsqr.f reference/ctbrfs.f reference/dorml2.f reference/sla_porfsx_extended.f reference/zggglm.f
reference/cgbbrd.f reference/ctbtrs.f reference/dormlq.f reference/sla_porpvgrw.f reference/zgghrd.f

232
lapack/clarf.f Normal file
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@@ -0,0 +1,232 @@
*> \brief \b CLARF
*
* =========== DOCUMENTATION ===========
*
* Online html documentation available at
* http://www.netlib.org/lapack/explore-html/
*
*> \htmlonly
*> Download CLARF + dependencies
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/clarf.f">
*> [TGZ]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/clarf.f">
*> [ZIP]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/clarf.f">
*> [TXT]</a>
*> \endhtmlonly
*
* Definition:
* ===========
*
* SUBROUTINE CLARF( SIDE, M, N, V, INCV, TAU, C, LDC, WORK )
*
* .. Scalar Arguments ..
* CHARACTER SIDE
* INTEGER INCV, LDC, M, N
* COMPLEX TAU
* ..
* .. Array Arguments ..
* COMPLEX C( LDC, * ), V( * ), WORK( * )
* ..
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> CLARF applies a complex elementary reflector H to a complex M-by-N
*> matrix C, from either the left or the right. H is represented in the
*> form
*>
*> H = I - tau * v * v**H
*>
*> where tau is a complex scalar and v is a complex vector.
*>
*> If tau = 0, then H is taken to be the unit matrix.
*>
*> To apply H**H (the conjugate transpose of H), supply conjg(tau) instead
*> tau.
*> \endverbatim
*
* Arguments:
* ==========
*
*> \param[in] SIDE
*> \verbatim
*> SIDE is CHARACTER*1
*> = 'L': form H * C
*> = 'R': form C * H
*> \endverbatim
*>
*> \param[in] M
*> \verbatim
*> M is INTEGER
*> The number of rows of the matrix C.
*> \endverbatim
*>
*> \param[in] N
*> \verbatim
*> N is INTEGER
*> The number of columns of the matrix C.
*> \endverbatim
*>
*> \param[in] V
*> \verbatim
*> V is COMPLEX array, dimension
*> (1 + (M-1)*abs(INCV)) if SIDE = 'L'
*> or (1 + (N-1)*abs(INCV)) if SIDE = 'R'
*> The vector v in the representation of H. V is not used if
*> TAU = 0.
*> \endverbatim
*>
*> \param[in] INCV
*> \verbatim
*> INCV is INTEGER
*> The increment between elements of v. INCV <> 0.
*> \endverbatim
*>
*> \param[in] TAU
*> \verbatim
*> TAU is COMPLEX
*> The value tau in the representation of H.
*> \endverbatim
*>
*> \param[in,out] C
*> \verbatim
*> C is COMPLEX array, dimension (LDC,N)
*> On entry, the M-by-N matrix C.
*> On exit, C is overwritten by the matrix H * C if SIDE = 'L',
*> or C * H if SIDE = 'R'.
*> \endverbatim
*>
*> \param[in] LDC
*> \verbatim
*> LDC is INTEGER
*> The leading dimension of the array C. LDC >= max(1,M).
*> \endverbatim
*>
*> \param[out] WORK
*> \verbatim
*> WORK is COMPLEX array, dimension
*> (N) if SIDE = 'L'
*> or (M) if SIDE = 'R'
*> \endverbatim
*
* Authors:
* ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \date November 2011
*
*> \ingroup complexOTHERauxiliary
*
* =====================================================================
SUBROUTINE CLARF( SIDE, M, N, V, INCV, TAU, C, LDC, WORK )
*
* -- LAPACK auxiliary routine (version 3.4.0) --
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
* November 2011
*
* .. Scalar Arguments ..
CHARACTER SIDE
INTEGER INCV, LDC, M, N
COMPLEX TAU
* ..
* .. Array Arguments ..
COMPLEX C( LDC, * ), V( * ), WORK( * )
* ..
*
* =====================================================================
*
* .. Parameters ..
COMPLEX ONE, ZERO
PARAMETER ( ONE = ( 1.0E+0, 0.0E+0 ),
$ ZERO = ( 0.0E+0, 0.0E+0 ) )
* ..
* .. Local Scalars ..
LOGICAL APPLYLEFT
INTEGER I, LASTV, LASTC
* ..
* .. External Subroutines ..
EXTERNAL CGEMV, CGERC
* ..
* .. External Functions ..
LOGICAL LSAME
INTEGER ILACLR, ILACLC
EXTERNAL LSAME, ILACLR, ILACLC
* ..
* .. Executable Statements ..
*
APPLYLEFT = LSAME( SIDE, 'L' )
LASTV = 0
LASTC = 0
IF( TAU.NE.ZERO ) THEN
! Set up variables for scanning V. LASTV begins pointing to the end
! of V.
IF( APPLYLEFT ) THEN
LASTV = M
ELSE
LASTV = N
END IF
IF( INCV.GT.0 ) THEN
I = 1 + (LASTV-1) * INCV
ELSE
I = 1
END IF
! Look for the last non-zero row in V.
DO WHILE( LASTV.GT.0 .AND. V( I ).EQ.ZERO )
LASTV = LASTV - 1
I = I - INCV
END DO
IF( APPLYLEFT ) THEN
! Scan for the last non-zero column in C(1:lastv,:).
LASTC = ILACLC(LASTV, N, C, LDC)
ELSE
! Scan for the last non-zero row in C(:,1:lastv).
LASTC = ILACLR(M, LASTV, C, LDC)
END IF
END IF
! Note that lastc.eq.0 renders the BLAS operations null; no special
! case is needed at this level.
IF( APPLYLEFT ) THEN
*
* Form H * C
*
IF( LASTV.GT.0 ) THEN
*
* w(1:lastc,1) := C(1:lastv,1:lastc)**H * v(1:lastv,1)
*
CALL CGEMV( 'Conjugate transpose', LASTV, LASTC, ONE,
$ C, LDC, V, INCV, ZERO, WORK, 1 )
*
* C(1:lastv,1:lastc) := C(...) - v(1:lastv,1) * w(1:lastc,1)**H
*
CALL CGERC( LASTV, LASTC, -TAU, V, INCV, WORK, 1, C, LDC )
END IF
ELSE
*
* Form C * H
*
IF( LASTV.GT.0 ) THEN
*
* w(1:lastc,1) := C(1:lastc,1:lastv) * v(1:lastv,1)
*
CALL CGEMV( 'No transpose', LASTC, LASTV, ONE, C, LDC,
$ V, INCV, ZERO, WORK, 1 )
*
* C(1:lastc,1:lastv) := C(...) - w(1:lastc,1) * v(1:lastv,1)**H
*
CALL CGERC( LASTC, LASTV, -TAU, WORK, 1, V, INCV, C, LDC )
END IF
END IF
RETURN
*
* End of CLARF
*
END

771
lapack/clarfb.f Normal file
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@@ -0,0 +1,771 @@
*> \brief \b CLARFB
*
* =========== DOCUMENTATION ===========
*
* Online html documentation available at
* http://www.netlib.org/lapack/explore-html/
*
*> \htmlonly
*> Download CLARFB + dependencies
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/clarfb.f">
*> [TGZ]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/clarfb.f">
*> [ZIP]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/clarfb.f">
*> [TXT]</a>
*> \endhtmlonly
*
* Definition:
* ===========
*
* SUBROUTINE CLARFB( SIDE, TRANS, DIRECT, STOREV, M, N, K, V, LDV,
* T, LDT, C, LDC, WORK, LDWORK )
*
* .. Scalar Arguments ..
* CHARACTER DIRECT, SIDE, STOREV, TRANS
* INTEGER K, LDC, LDT, LDV, LDWORK, M, N
* ..
* .. Array Arguments ..
* COMPLEX C( LDC, * ), T( LDT, * ), V( LDV, * ),
* $ WORK( LDWORK, * )
* ..
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> CLARFB applies a complex block reflector H or its transpose H**H to a
*> complex M-by-N matrix C, from either the left or the right.
*> \endverbatim
*
* Arguments:
* ==========
*
*> \param[in] SIDE
*> \verbatim
*> SIDE is CHARACTER*1
*> = 'L': apply H or H**H from the Left
*> = 'R': apply H or H**H from the Right
*> \endverbatim
*>
*> \param[in] TRANS
*> \verbatim
*> TRANS is CHARACTER*1
*> = 'N': apply H (No transpose)
*> = 'C': apply H**H (Conjugate transpose)
*> \endverbatim
*>
*> \param[in] DIRECT
*> \verbatim
*> DIRECT is CHARACTER*1
*> Indicates how H is formed from a product of elementary
*> reflectors
*> = 'F': H = H(1) H(2) . . . H(k) (Forward)
*> = 'B': H = H(k) . . . H(2) H(1) (Backward)
*> \endverbatim
*>
*> \param[in] STOREV
*> \verbatim
*> STOREV is CHARACTER*1
*> Indicates how the vectors which define the elementary
*> reflectors are stored:
*> = 'C': Columnwise
*> = 'R': Rowwise
*> \endverbatim
*>
*> \param[in] M
*> \verbatim
*> M is INTEGER
*> The number of rows of the matrix C.
*> \endverbatim
*>
*> \param[in] N
*> \verbatim
*> N is INTEGER
*> The number of columns of the matrix C.
*> \endverbatim
*>
*> \param[in] K
*> \verbatim
*> K is INTEGER
*> The order of the matrix T (= the number of elementary
*> reflectors whose product defines the block reflector).
*> \endverbatim
*>
*> \param[in] V
*> \verbatim
*> V is COMPLEX array, dimension
*> (LDV,K) if STOREV = 'C'
*> (LDV,M) if STOREV = 'R' and SIDE = 'L'
*> (LDV,N) if STOREV = 'R' and SIDE = 'R'
*> The matrix V. See Further Details.
*> \endverbatim
*>
*> \param[in] LDV
*> \verbatim
*> LDV is INTEGER
*> The leading dimension of the array V.
*> If STOREV = 'C' and SIDE = 'L', LDV >= max(1,M);
*> if STOREV = 'C' and SIDE = 'R', LDV >= max(1,N);
*> if STOREV = 'R', LDV >= K.
*> \endverbatim
*>
*> \param[in] T
*> \verbatim
*> T is COMPLEX array, dimension (LDT,K)
*> The triangular K-by-K matrix T in the representation of the
*> block reflector.
*> \endverbatim
*>
*> \param[in] LDT
*> \verbatim
*> LDT is INTEGER
*> The leading dimension of the array T. LDT >= K.
*> \endverbatim
*>
*> \param[in,out] C
*> \verbatim
*> C is COMPLEX array, dimension (LDC,N)
*> On entry, the M-by-N matrix C.
*> On exit, C is overwritten by H*C or H**H*C or C*H or C*H**H.
*> \endverbatim
*>
*> \param[in] LDC
*> \verbatim
*> LDC is INTEGER
*> The leading dimension of the array C. LDC >= max(1,M).
*> \endverbatim
*>
*> \param[out] WORK
*> \verbatim
*> WORK is COMPLEX array, dimension (LDWORK,K)
*> \endverbatim
*>
*> \param[in] LDWORK
*> \verbatim
*> LDWORK is INTEGER
*> The leading dimension of the array WORK.
*> If SIDE = 'L', LDWORK >= max(1,N);
*> if SIDE = 'R', LDWORK >= max(1,M).
*> \endverbatim
*
* Authors:
* ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \date November 2011
*
*> \ingroup complexOTHERauxiliary
*
*> \par Further Details:
* =====================
*>
*> \verbatim
*>
*> The shape of the matrix V and the storage of the vectors which define
*> the H(i) is best illustrated by the following example with n = 5 and
*> k = 3. The elements equal to 1 are not stored; the corresponding
*> array elements are modified but restored on exit. The rest of the
*> array is not used.
*>
*> DIRECT = 'F' and STOREV = 'C': DIRECT = 'F' and STOREV = 'R':
*>
*> V = ( 1 ) V = ( 1 v1 v1 v1 v1 )
*> ( v1 1 ) ( 1 v2 v2 v2 )
*> ( v1 v2 1 ) ( 1 v3 v3 )
*> ( v1 v2 v3 )
*> ( v1 v2 v3 )
*>
*> DIRECT = 'B' and STOREV = 'C': DIRECT = 'B' and STOREV = 'R':
*>
*> V = ( v1 v2 v3 ) V = ( v1 v1 1 )
*> ( v1 v2 v3 ) ( v2 v2 v2 1 )
*> ( 1 v2 v3 ) ( v3 v3 v3 v3 1 )
*> ( 1 v3 )
*> ( 1 )
*> \endverbatim
*>
* =====================================================================
SUBROUTINE CLARFB( SIDE, TRANS, DIRECT, STOREV, M, N, K, V, LDV,
$ T, LDT, C, LDC, WORK, LDWORK )
*
* -- LAPACK auxiliary routine (version 3.4.0) --
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
* November 2011
*
* .. Scalar Arguments ..
CHARACTER DIRECT, SIDE, STOREV, TRANS
INTEGER K, LDC, LDT, LDV, LDWORK, M, N
* ..
* .. Array Arguments ..
COMPLEX C( LDC, * ), T( LDT, * ), V( LDV, * ),
$ WORK( LDWORK, * )
* ..
*
* =====================================================================
*
* .. Parameters ..
COMPLEX ONE
PARAMETER ( ONE = ( 1.0E+0, 0.0E+0 ) )
* ..
* .. Local Scalars ..
CHARACTER TRANST
INTEGER I, J, LASTV, LASTC
* ..
* .. External Functions ..
LOGICAL LSAME
INTEGER ILACLR, ILACLC
EXTERNAL LSAME, ILACLR, ILACLC
* ..
* .. External Subroutines ..
EXTERNAL CCOPY, CGEMM, CLACGV, CTRMM
* ..
* .. Intrinsic Functions ..
INTRINSIC CONJG
* ..
* .. Executable Statements ..
*
* Quick return if possible
*
IF( M.LE.0 .OR. N.LE.0 )
$ RETURN
*
IF( LSAME( TRANS, 'N' ) ) THEN
TRANST = 'C'
ELSE
TRANST = 'N'
END IF
*
IF( LSAME( STOREV, 'C' ) ) THEN
*
IF( LSAME( DIRECT, 'F' ) ) THEN
*
* Let V = ( V1 ) (first K rows)
* ( V2 )
* where V1 is unit lower triangular.
*
IF( LSAME( SIDE, 'L' ) ) THEN
*
* Form H * C or H**H * C where C = ( C1 )
* ( C2 )
*
LASTV = MAX( K, ILACLR( M, K, V, LDV ) )
LASTC = ILACLC( LASTV, N, C, LDC )
*
* W := C**H * V = (C1**H * V1 + C2**H * V2) (stored in WORK)
*
* W := C1**H
*
DO 10 J = 1, K
CALL CCOPY( LASTC, C( J, 1 ), LDC, WORK( 1, J ), 1 )
CALL CLACGV( LASTC, WORK( 1, J ), 1 )
10 CONTINUE
*
* W := W * V1
*
CALL CTRMM( 'Right', 'Lower', 'No transpose', 'Unit',
$ LASTC, K, ONE, V, LDV, WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C2**H *V2
*
CALL CGEMM( 'Conjugate transpose', 'No transpose',
$ LASTC, K, LASTV-K, ONE, C( K+1, 1 ), LDC,
$ V( K+1, 1 ), LDV, ONE, WORK, LDWORK )
END IF
*
* W := W * T**H or W * T
*
CALL CTRMM( 'Right', 'Upper', TRANST, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - V * W**H
*
IF( M.GT.K ) THEN
*
* C2 := C2 - V2 * W**H
*
CALL CGEMM( 'No transpose', 'Conjugate transpose',
$ LASTV-K, LASTC, K, -ONE, V( K+1, 1 ), LDV,
$ WORK, LDWORK, ONE, C( K+1, 1 ), LDC )
END IF
*
* W := W * V1**H
*
CALL CTRMM( 'Right', 'Lower', 'Conjugate transpose',
$ 'Unit', LASTC, K, ONE, V, LDV, WORK, LDWORK )
*
* C1 := C1 - W**H
*
DO 30 J = 1, K
DO 20 I = 1, LASTC
C( J, I ) = C( J, I ) - CONJG( WORK( I, J ) )
20 CONTINUE
30 CONTINUE
*
ELSE IF( LSAME( SIDE, 'R' ) ) THEN
*
* Form C * H or C * H**H where C = ( C1 C2 )
*
LASTV = MAX( K, ILACLR( N, K, V, LDV ) )
LASTC = ILACLR( M, LASTV, C, LDC )
*
* W := C * V = (C1*V1 + C2*V2) (stored in WORK)
*
* W := C1
*
DO 40 J = 1, K
CALL CCOPY( LASTC, C( 1, J ), 1, WORK( 1, J ), 1 )
40 CONTINUE
*
* W := W * V1
*
CALL CTRMM( 'Right', 'Lower', 'No transpose', 'Unit',
$ LASTC, K, ONE, V, LDV, WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C2 * V2
*
CALL CGEMM( 'No transpose', 'No transpose',
$ LASTC, K, LASTV-K,
$ ONE, C( 1, K+1 ), LDC, V( K+1, 1 ), LDV,
$ ONE, WORK, LDWORK )
END IF
*
* W := W * T or W * T**H
*
CALL CTRMM( 'Right', 'Upper', TRANS, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - W * V**H
*
IF( LASTV.GT.K ) THEN
*
* C2 := C2 - W * V2**H
*
CALL CGEMM( 'No transpose', 'Conjugate transpose',
$ LASTC, LASTV-K, K,
$ -ONE, WORK, LDWORK, V( K+1, 1 ), LDV,
$ ONE, C( 1, K+1 ), LDC )
END IF
*
* W := W * V1**H
*
CALL CTRMM( 'Right', 'Lower', 'Conjugate transpose',
$ 'Unit', LASTC, K, ONE, V, LDV, WORK, LDWORK )
*
* C1 := C1 - W
*
DO 60 J = 1, K
DO 50 I = 1, LASTC
C( I, J ) = C( I, J ) - WORK( I, J )
50 CONTINUE
60 CONTINUE
END IF
*
ELSE
*
* Let V = ( V1 )
* ( V2 ) (last K rows)
* where V2 is unit upper triangular.
*
IF( LSAME( SIDE, 'L' ) ) THEN
*
* Form H * C or H**H * C where C = ( C1 )
* ( C2 )
*
LASTV = MAX( K, ILACLR( M, K, V, LDV ) )
LASTC = ILACLC( LASTV, N, C, LDC )
*
* W := C**H * V = (C1**H * V1 + C2**H * V2) (stored in WORK)
*
* W := C2**H
*
DO 70 J = 1, K
CALL CCOPY( LASTC, C( LASTV-K+J, 1 ), LDC,
$ WORK( 1, J ), 1 )
CALL CLACGV( LASTC, WORK( 1, J ), 1 )
70 CONTINUE
*
* W := W * V2
*
CALL CTRMM( 'Right', 'Upper', 'No transpose', 'Unit',
$ LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
$ WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C1**H*V1
*
CALL CGEMM( 'Conjugate transpose', 'No transpose',
$ LASTC, K, LASTV-K, ONE, C, LDC, V, LDV,
$ ONE, WORK, LDWORK )
END IF
*
* W := W * T**H or W * T
*
CALL CTRMM( 'Right', 'Lower', TRANST, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - V * W**H
*
IF( LASTV.GT.K ) THEN
*
* C1 := C1 - V1 * W**H
*
CALL CGEMM( 'No transpose', 'Conjugate transpose',
$ LASTV-K, LASTC, K, -ONE, V, LDV, WORK, LDWORK,
$ ONE, C, LDC )
END IF
*
* W := W * V2**H
*
CALL CTRMM( 'Right', 'Upper', 'Conjugate transpose',
$ 'Unit', LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
$ WORK, LDWORK )
*
* C2 := C2 - W**H
*
DO 90 J = 1, K
DO 80 I = 1, LASTC
C( LASTV-K+J, I ) = C( LASTV-K+J, I ) -
$ CONJG( WORK( I, J ) )
80 CONTINUE
90 CONTINUE
*
ELSE IF( LSAME( SIDE, 'R' ) ) THEN
*
* Form C * H or C * H**H where C = ( C1 C2 )
*
LASTV = MAX( K, ILACLR( N, K, V, LDV ) )
LASTC = ILACLR( M, LASTV, C, LDC )
*
* W := C * V = (C1*V1 + C2*V2) (stored in WORK)
*
* W := C2
*
DO 100 J = 1, K
CALL CCOPY( LASTC, C( 1, LASTV-K+J ), 1,
$ WORK( 1, J ), 1 )
100 CONTINUE
*
* W := W * V2
*
CALL CTRMM( 'Right', 'Upper', 'No transpose', 'Unit',
$ LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
$ WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C1 * V1
*
CALL CGEMM( 'No transpose', 'No transpose',
$ LASTC, K, LASTV-K,
$ ONE, C, LDC, V, LDV, ONE, WORK, LDWORK )
END IF
*
* W := W * T or W * T**H
*
CALL CTRMM( 'Right', 'Lower', TRANS, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - W * V**H
*
IF( LASTV.GT.K ) THEN
*
* C1 := C1 - W * V1**H
*
CALL CGEMM( 'No transpose', 'Conjugate transpose',
$ LASTC, LASTV-K, K, -ONE, WORK, LDWORK, V, LDV,
$ ONE, C, LDC )
END IF
*
* W := W * V2**H
*
CALL CTRMM( 'Right', 'Upper', 'Conjugate transpose',
$ 'Unit', LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
$ WORK, LDWORK )
*
* C2 := C2 - W
*
DO 120 J = 1, K
DO 110 I = 1, LASTC
C( I, LASTV-K+J ) = C( I, LASTV-K+J )
$ - WORK( I, J )
110 CONTINUE
120 CONTINUE
END IF
END IF
*
ELSE IF( LSAME( STOREV, 'R' ) ) THEN
*
IF( LSAME( DIRECT, 'F' ) ) THEN
*
* Let V = ( V1 V2 ) (V1: first K columns)
* where V1 is unit upper triangular.
*
IF( LSAME( SIDE, 'L' ) ) THEN
*
* Form H * C or H**H * C where C = ( C1 )
* ( C2 )
*
LASTV = MAX( K, ILACLC( K, M, V, LDV ) )
LASTC = ILACLC( LASTV, N, C, LDC )
*
* W := C**H * V**H = (C1**H * V1**H + C2**H * V2**H) (stored in WORK)
*
* W := C1**H
*
DO 130 J = 1, K
CALL CCOPY( LASTC, C( J, 1 ), LDC, WORK( 1, J ), 1 )
CALL CLACGV( LASTC, WORK( 1, J ), 1 )
130 CONTINUE
*
* W := W * V1**H
*
CALL CTRMM( 'Right', 'Upper', 'Conjugate transpose',
$ 'Unit', LASTC, K, ONE, V, LDV, WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C2**H*V2**H
*
CALL CGEMM( 'Conjugate transpose',
$ 'Conjugate transpose', LASTC, K, LASTV-K,
$ ONE, C( K+1, 1 ), LDC, V( 1, K+1 ), LDV,
$ ONE, WORK, LDWORK )
END IF
*
* W := W * T**H or W * T
*
CALL CTRMM( 'Right', 'Upper', TRANST, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - V**H * W**H
*
IF( LASTV.GT.K ) THEN
*
* C2 := C2 - V2**H * W**H
*
CALL CGEMM( 'Conjugate transpose',
$ 'Conjugate transpose', LASTV-K, LASTC, K,
$ -ONE, V( 1, K+1 ), LDV, WORK, LDWORK,
$ ONE, C( K+1, 1 ), LDC )
END IF
*
* W := W * V1
*
CALL CTRMM( 'Right', 'Upper', 'No transpose', 'Unit',
$ LASTC, K, ONE, V, LDV, WORK, LDWORK )
*
* C1 := C1 - W**H
*
DO 150 J = 1, K
DO 140 I = 1, LASTC
C( J, I ) = C( J, I ) - CONJG( WORK( I, J ) )
140 CONTINUE
150 CONTINUE
*
ELSE IF( LSAME( SIDE, 'R' ) ) THEN
*
* Form C * H or C * H**H where C = ( C1 C2 )
*
LASTV = MAX( K, ILACLC( K, N, V, LDV ) )
LASTC = ILACLR( M, LASTV, C, LDC )
*
* W := C * V**H = (C1*V1**H + C2*V2**H) (stored in WORK)
*
* W := C1
*
DO 160 J = 1, K
CALL CCOPY( LASTC, C( 1, J ), 1, WORK( 1, J ), 1 )
160 CONTINUE
*
* W := W * V1**H
*
CALL CTRMM( 'Right', 'Upper', 'Conjugate transpose',
$ 'Unit', LASTC, K, ONE, V, LDV, WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C2 * V2**H
*
CALL CGEMM( 'No transpose', 'Conjugate transpose',
$ LASTC, K, LASTV-K, ONE, C( 1, K+1 ), LDC,
$ V( 1, K+1 ), LDV, ONE, WORK, LDWORK )
END IF
*
* W := W * T or W * T**H
*
CALL CTRMM( 'Right', 'Upper', TRANS, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - W * V
*
IF( LASTV.GT.K ) THEN
*
* C2 := C2 - W * V2
*
CALL CGEMM( 'No transpose', 'No transpose',
$ LASTC, LASTV-K, K,
$ -ONE, WORK, LDWORK, V( 1, K+1 ), LDV,
$ ONE, C( 1, K+1 ), LDC )
END IF
*
* W := W * V1
*
CALL CTRMM( 'Right', 'Upper', 'No transpose', 'Unit',
$ LASTC, K, ONE, V, LDV, WORK, LDWORK )
*
* C1 := C1 - W
*
DO 180 J = 1, K
DO 170 I = 1, LASTC
C( I, J ) = C( I, J ) - WORK( I, J )
170 CONTINUE
180 CONTINUE
*
END IF
*
ELSE
*
* Let V = ( V1 V2 ) (V2: last K columns)
* where V2 is unit lower triangular.
*
IF( LSAME( SIDE, 'L' ) ) THEN
*
* Form H * C or H**H * C where C = ( C1 )
* ( C2 )
*
LASTV = MAX( K, ILACLC( K, M, V, LDV ) )
LASTC = ILACLC( LASTV, N, C, LDC )
*
* W := C**H * V**H = (C1**H * V1**H + C2**H * V2**H) (stored in WORK)
*
* W := C2**H
*
DO 190 J = 1, K
CALL CCOPY( LASTC, C( LASTV-K+J, 1 ), LDC,
$ WORK( 1, J ), 1 )
CALL CLACGV( LASTC, WORK( 1, J ), 1 )
190 CONTINUE
*
* W := W * V2**H
*
CALL CTRMM( 'Right', 'Lower', 'Conjugate transpose',
$ 'Unit', LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV,
$ WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C1**H * V1**H
*
CALL CGEMM( 'Conjugate transpose',
$ 'Conjugate transpose', LASTC, K, LASTV-K,
$ ONE, C, LDC, V, LDV, ONE, WORK, LDWORK )
END IF
*
* W := W * T**H or W * T
*
CALL CTRMM( 'Right', 'Lower', TRANST, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - V**H * W**H
*
IF( LASTV.GT.K ) THEN
*
* C1 := C1 - V1**H * W**H
*
CALL CGEMM( 'Conjugate transpose',
$ 'Conjugate transpose', LASTV-K, LASTC, K,
$ -ONE, V, LDV, WORK, LDWORK, ONE, C, LDC )
END IF
*
* W := W * V2
*
CALL CTRMM( 'Right', 'Lower', 'No transpose', 'Unit',
$ LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV,
$ WORK, LDWORK )
*
* C2 := C2 - W**H
*
DO 210 J = 1, K
DO 200 I = 1, LASTC
C( LASTV-K+J, I ) = C( LASTV-K+J, I ) -
$ CONJG( WORK( I, J ) )
200 CONTINUE
210 CONTINUE
*
ELSE IF( LSAME( SIDE, 'R' ) ) THEN
*
* Form C * H or C * H**H where C = ( C1 C2 )
*
LASTV = MAX( K, ILACLC( K, N, V, LDV ) )
LASTC = ILACLR( M, LASTV, C, LDC )
*
* W := C * V**H = (C1*V1**H + C2*V2**H) (stored in WORK)
*
* W := C2
*
DO 220 J = 1, K
CALL CCOPY( LASTC, C( 1, LASTV-K+J ), 1,
$ WORK( 1, J ), 1 )
220 CONTINUE
*
* W := W * V2**H
*
CALL CTRMM( 'Right', 'Lower', 'Conjugate transpose',
$ 'Unit', LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV,
$ WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C1 * V1**H
*
CALL CGEMM( 'No transpose', 'Conjugate transpose',
$ LASTC, K, LASTV-K, ONE, C, LDC, V, LDV, ONE,
$ WORK, LDWORK )
END IF
*
* W := W * T or W * T**H
*
CALL CTRMM( 'Right', 'Lower', TRANS, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - W * V
*
IF( LASTV.GT.K ) THEN
*
* C1 := C1 - W * V1
*
CALL CGEMM( 'No transpose', 'No transpose',
$ LASTC, LASTV-K, K, -ONE, WORK, LDWORK, V, LDV,
$ ONE, C, LDC )
END IF
*
* W := W * V2
*
CALL CTRMM( 'Right', 'Lower', 'No transpose', 'Unit',
$ LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV,
$ WORK, LDWORK )
*
* C1 := C1 - W
*
DO 240 J = 1, K
DO 230 I = 1, LASTC
C( I, LASTV-K+J ) = C( I, LASTV-K+J )
$ - WORK( I, J )
230 CONTINUE
240 CONTINUE
*
END IF
*
END IF
END IF
*
RETURN
*
* End of CLARFB
*
END

203
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*> \brief \b CLARFG
*
* =========== DOCUMENTATION ===========
*
* Online html documentation available at
* http://www.netlib.org/lapack/explore-html/
*
*> \htmlonly
*> Download CLARFG + dependencies
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/clarfg.f">
*> [TGZ]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/clarfg.f">
*> [ZIP]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/clarfg.f">
*> [TXT]</a>
*> \endhtmlonly
*
* Definition:
* ===========
*
* SUBROUTINE CLARFG( N, ALPHA, X, INCX, TAU )
*
* .. Scalar Arguments ..
* INTEGER INCX, N
* COMPLEX ALPHA, TAU
* ..
* .. Array Arguments ..
* COMPLEX X( * )
* ..
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> CLARFG generates a complex elementary reflector H of order n, such
*> that
*>
*> H**H * ( alpha ) = ( beta ), H**H * H = I.
*> ( x ) ( 0 )
*>
*> where alpha and beta are scalars, with beta real, and x is an
*> (n-1)-element complex vector. H is represented in the form
*>
*> H = I - tau * ( 1 ) * ( 1 v**H ) ,
*> ( v )
*>
*> where tau is a complex scalar and v is a complex (n-1)-element
*> vector. Note that H is not hermitian.
*>
*> If the elements of x are all zero and alpha is real, then tau = 0
*> and H is taken to be the unit matrix.
*>
*> Otherwise 1 <= real(tau) <= 2 and abs(tau-1) <= 1 .
*> \endverbatim
*
* Arguments:
* ==========
*
*> \param[in] N
*> \verbatim
*> N is INTEGER
*> The order of the elementary reflector.
*> \endverbatim
*>
*> \param[in,out] ALPHA
*> \verbatim
*> ALPHA is COMPLEX
*> On entry, the value alpha.
*> On exit, it is overwritten with the value beta.
*> \endverbatim
*>
*> \param[in,out] X
*> \verbatim
*> X is COMPLEX array, dimension
*> (1+(N-2)*abs(INCX))
*> On entry, the vector x.
*> On exit, it is overwritten with the vector v.
*> \endverbatim
*>
*> \param[in] INCX
*> \verbatim
*> INCX is INTEGER
*> The increment between elements of X. INCX > 0.
*> \endverbatim
*>
*> \param[out] TAU
*> \verbatim
*> TAU is COMPLEX
*> The value tau.
*> \endverbatim
*
* Authors:
* ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \date November 2011
*
*> \ingroup complexOTHERauxiliary
*
* =====================================================================
SUBROUTINE CLARFG( N, ALPHA, X, INCX, TAU )
*
* -- LAPACK auxiliary routine (version 3.4.0) --
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
* November 2011
*
* .. Scalar Arguments ..
INTEGER INCX, N
COMPLEX ALPHA, TAU
* ..
* .. Array Arguments ..
COMPLEX X( * )
* ..
*
* =====================================================================
*
* .. Parameters ..
REAL ONE, ZERO
PARAMETER ( ONE = 1.0E+0, ZERO = 0.0E+0 )
* ..
* .. Local Scalars ..
INTEGER J, KNT
REAL ALPHI, ALPHR, BETA, RSAFMN, SAFMIN, XNORM
* ..
* .. External Functions ..
REAL SCNRM2, SLAMCH, SLAPY3
COMPLEX CLADIV
EXTERNAL SCNRM2, SLAMCH, SLAPY3, CLADIV
* ..
* .. Intrinsic Functions ..
INTRINSIC ABS, AIMAG, CMPLX, REAL, SIGN
* ..
* .. External Subroutines ..
EXTERNAL CSCAL, CSSCAL
* ..
* .. Executable Statements ..
*
IF( N.LE.0 ) THEN
TAU = ZERO
RETURN
END IF
*
XNORM = SCNRM2( N-1, X, INCX )
ALPHR = REAL( ALPHA )
ALPHI = AIMAG( ALPHA )
*
IF( XNORM.EQ.ZERO .AND. ALPHI.EQ.ZERO ) THEN
*
* H = I
*
TAU = ZERO
ELSE
*
* general case
*
BETA = -SIGN( SLAPY3( ALPHR, ALPHI, XNORM ), ALPHR )
SAFMIN = SLAMCH( 'S' ) / SLAMCH( 'E' )
RSAFMN = ONE / SAFMIN
*
KNT = 0
IF( ABS( BETA ).LT.SAFMIN ) THEN
*
* XNORM, BETA may be inaccurate; scale X and recompute them
*
10 CONTINUE
KNT = KNT + 1
CALL CSSCAL( N-1, RSAFMN, X, INCX )
BETA = BETA*RSAFMN
ALPHI = ALPHI*RSAFMN
ALPHR = ALPHR*RSAFMN
IF( ABS( BETA ).LT.SAFMIN )
$ GO TO 10
*
* New BETA is at most 1, at least SAFMIN
*
XNORM = SCNRM2( N-1, X, INCX )
ALPHA = CMPLX( ALPHR, ALPHI )
BETA = -SIGN( SLAPY3( ALPHR, ALPHI, XNORM ), ALPHR )
END IF
TAU = CMPLX( ( BETA-ALPHR ) / BETA, -ALPHI / BETA )
ALPHA = CLADIV( CMPLX( ONE ), ALPHA-BETA )
CALL CSCAL( N-1, ALPHA, X, INCX )
*
* If ALPHA is subnormal, it may lose relative accuracy
*
DO 20 J = 1, KNT
BETA = BETA*SAFMIN
20 CONTINUE
ALPHA = BETA
END IF
*
RETURN
*
* End of CLARFG
*
END

328
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*> \brief \b CLARFT
*
* =========== DOCUMENTATION ===========
*
* Online html documentation available at
* http://www.netlib.org/lapack/explore-html/
*
*> \htmlonly
*> Download CLARFT + dependencies
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/clarft.f">
*> [TGZ]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/clarft.f">
*> [ZIP]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/clarft.f">
*> [TXT]</a>
*> \endhtmlonly
*
* Definition:
* ===========
*
* SUBROUTINE CLARFT( DIRECT, STOREV, N, K, V, LDV, TAU, T, LDT )
*
* .. Scalar Arguments ..
* CHARACTER DIRECT, STOREV
* INTEGER K, LDT, LDV, N
* ..
* .. Array Arguments ..
* COMPLEX T( LDT, * ), TAU( * ), V( LDV, * )
* ..
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> CLARFT forms the triangular factor T of a complex block reflector H
*> of order n, which is defined as a product of k elementary reflectors.
*>
*> If DIRECT = 'F', H = H(1) H(2) . . . H(k) and T is upper triangular;
*>
*> If DIRECT = 'B', H = H(k) . . . H(2) H(1) and T is lower triangular.
*>
*> If STOREV = 'C', the vector which defines the elementary reflector
*> H(i) is stored in the i-th column of the array V, and
*>
*> H = I - V * T * V**H
*>
*> If STOREV = 'R', the vector which defines the elementary reflector
*> H(i) is stored in the i-th row of the array V, and
*>
*> H = I - V**H * T * V
*> \endverbatim
*
* Arguments:
* ==========
*
*> \param[in] DIRECT
*> \verbatim
*> DIRECT is CHARACTER*1
*> Specifies the order in which the elementary reflectors are
*> multiplied to form the block reflector:
*> = 'F': H = H(1) H(2) . . . H(k) (Forward)
*> = 'B': H = H(k) . . . H(2) H(1) (Backward)
*> \endverbatim
*>
*> \param[in] STOREV
*> \verbatim
*> STOREV is CHARACTER*1
*> Specifies how the vectors which define the elementary
*> reflectors are stored (see also Further Details):
*> = 'C': columnwise
*> = 'R': rowwise
*> \endverbatim
*>
*> \param[in] N
*> \verbatim
*> N is INTEGER
*> The order of the block reflector H. N >= 0.
*> \endverbatim
*>
*> \param[in] K
*> \verbatim
*> K is INTEGER
*> The order of the triangular factor T (= the number of
*> elementary reflectors). K >= 1.
*> \endverbatim
*>
*> \param[in] V
*> \verbatim
*> V is COMPLEX array, dimension
*> (LDV,K) if STOREV = 'C'
*> (LDV,N) if STOREV = 'R'
*> The matrix V. See further details.
*> \endverbatim
*>
*> \param[in] LDV
*> \verbatim
*> LDV is INTEGER
*> The leading dimension of the array V.
*> If STOREV = 'C', LDV >= max(1,N); if STOREV = 'R', LDV >= K.
*> \endverbatim
*>
*> \param[in] TAU
*> \verbatim
*> TAU is COMPLEX array, dimension (K)
*> TAU(i) must contain the scalar factor of the elementary
*> reflector H(i).
*> \endverbatim
*>
*> \param[out] T
*> \verbatim
*> T is COMPLEX array, dimension (LDT,K)
*> The k by k triangular factor T of the block reflector.
*> If DIRECT = 'F', T is upper triangular; if DIRECT = 'B', T is
*> lower triangular. The rest of the array is not used.
*> \endverbatim
*>
*> \param[in] LDT
*> \verbatim
*> LDT is INTEGER
*> The leading dimension of the array T. LDT >= K.
*> \endverbatim
*
* Authors:
* ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \date April 2012
*
*> \ingroup complexOTHERauxiliary
*
*> \par Further Details:
* =====================
*>
*> \verbatim
*>
*> The shape of the matrix V and the storage of the vectors which define
*> the H(i) is best illustrated by the following example with n = 5 and
*> k = 3. The elements equal to 1 are not stored.
*>
*> DIRECT = 'F' and STOREV = 'C': DIRECT = 'F' and STOREV = 'R':
*>
*> V = ( 1 ) V = ( 1 v1 v1 v1 v1 )
*> ( v1 1 ) ( 1 v2 v2 v2 )
*> ( v1 v2 1 ) ( 1 v3 v3 )
*> ( v1 v2 v3 )
*> ( v1 v2 v3 )
*>
*> DIRECT = 'B' and STOREV = 'C': DIRECT = 'B' and STOREV = 'R':
*>
*> V = ( v1 v2 v3 ) V = ( v1 v1 1 )
*> ( v1 v2 v3 ) ( v2 v2 v2 1 )
*> ( 1 v2 v3 ) ( v3 v3 v3 v3 1 )
*> ( 1 v3 )
*> ( 1 )
*> \endverbatim
*>
* =====================================================================
SUBROUTINE CLARFT( DIRECT, STOREV, N, K, V, LDV, TAU, T, LDT )
*
* -- LAPACK auxiliary routine (version 3.4.1) --
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
* April 2012
*
* .. Scalar Arguments ..
CHARACTER DIRECT, STOREV
INTEGER K, LDT, LDV, N
* ..
* .. Array Arguments ..
COMPLEX T( LDT, * ), TAU( * ), V( LDV, * )
* ..
*
* =====================================================================
*
* .. Parameters ..
COMPLEX ONE, ZERO
PARAMETER ( ONE = ( 1.0E+0, 0.0E+0 ),
$ ZERO = ( 0.0E+0, 0.0E+0 ) )
* ..
* .. Local Scalars ..
INTEGER I, J, PREVLASTV, LASTV
* ..
* .. External Subroutines ..
EXTERNAL CGEMV, CLACGV, CTRMV
* ..
* .. External Functions ..
LOGICAL LSAME
EXTERNAL LSAME
* ..
* .. Executable Statements ..
*
* Quick return if possible
*
IF( N.EQ.0 )
$ RETURN
*
IF( LSAME( DIRECT, 'F' ) ) THEN
PREVLASTV = N
DO I = 1, K
PREVLASTV = MAX( PREVLASTV, I )
IF( TAU( I ).EQ.ZERO ) THEN
*
* H(i) = I
*
DO J = 1, I
T( J, I ) = ZERO
END DO
ELSE
*
* general case
*
IF( LSAME( STOREV, 'C' ) ) THEN
* Skip any trailing zeros.
DO LASTV = N, I+1, -1
IF( V( LASTV, I ).NE.ZERO ) EXIT
END DO
DO J = 1, I-1
T( J, I ) = -TAU( I ) * CONJG( V( I , J ) )
END DO
J = MIN( LASTV, PREVLASTV )
*
* T(1:i-1,i) := - tau(i) * V(i:j,1:i-1)**H * V(i:j,i)
*
CALL CGEMV( 'Conjugate transpose', J-I, I-1,
$ -TAU( I ), V( I+1, 1 ), LDV,
$ V( I+1, I ), 1,
$ ONE, T( 1, I ), 1 )
ELSE
* Skip any trailing zeros.
DO LASTV = N, I+1, -1
IF( V( I, LASTV ).NE.ZERO ) EXIT
END DO
DO J = 1, I-1
T( J, I ) = -TAU( I ) * V( J , I )
END DO
J = MIN( LASTV, PREVLASTV )
*
* T(1:i-1,i) := - tau(i) * V(1:i-1,i:j) * V(i,i:j)**H
*
CALL CGEMM( 'N', 'C', I-1, 1, J-I, -TAU( I ),
$ V( 1, I+1 ), LDV, V( I, I+1 ), LDV,
$ ONE, T( 1, I ), LDT )
END IF
*
* T(1:i-1,i) := T(1:i-1,1:i-1) * T(1:i-1,i)
*
CALL CTRMV( 'Upper', 'No transpose', 'Non-unit', I-1, T,
$ LDT, T( 1, I ), 1 )
T( I, I ) = TAU( I )
IF( I.GT.1 ) THEN
PREVLASTV = MAX( PREVLASTV, LASTV )
ELSE
PREVLASTV = LASTV
END IF
END IF
END DO
ELSE
PREVLASTV = 1
DO I = K, 1, -1
IF( TAU( I ).EQ.ZERO ) THEN
*
* H(i) = I
*
DO J = I, K
T( J, I ) = ZERO
END DO
ELSE
*
* general case
*
IF( I.LT.K ) THEN
IF( LSAME( STOREV, 'C' ) ) THEN
* Skip any leading zeros.
DO LASTV = 1, I-1
IF( V( LASTV, I ).NE.ZERO ) EXIT
END DO
DO J = I+1, K
T( J, I ) = -TAU( I ) * CONJG( V( N-K+I , J ) )
END DO
J = MAX( LASTV, PREVLASTV )
*
* T(i+1:k,i) = -tau(i) * V(j:n-k+i,i+1:k)**H * V(j:n-k+i,i)
*
CALL CGEMV( 'Conjugate transpose', N-K+I-J, K-I,
$ -TAU( I ), V( J, I+1 ), LDV, V( J, I ),
$ 1, ONE, T( I+1, I ), 1 )
ELSE
* Skip any leading zeros.
DO LASTV = 1, I-1
IF( V( I, LASTV ).NE.ZERO ) EXIT
END DO
DO J = I+1, K
T( J, I ) = -TAU( I ) * V( J, N-K+I )
END DO
J = MAX( LASTV, PREVLASTV )
*
* T(i+1:k,i) = -tau(i) * V(i+1:k,j:n-k+i) * V(i,j:n-k+i)**H
*
CALL CGEMM( 'N', 'C', K-I, 1, N-K+I-J, -TAU( I ),
$ V( I+1, J ), LDV, V( I, J ), LDV,
$ ONE, T( I+1, I ), LDT )
END IF
*
* T(i+1:k,i) := T(i+1:k,i+1:k) * T(i+1:k,i)
*
CALL CTRMV( 'Lower', 'No transpose', 'Non-unit', K-I,
$ T( I+1, I+1 ), LDT, T( I+1, I ), 1 )
IF( I.GT.1 ) THEN
PREVLASTV = MIN( PREVLASTV, LASTV )
ELSE
PREVLASTV = LASTV
END IF
END IF
T( I, I ) = TAU( I )
END IF
END DO
END IF
RETURN
*
* End of CLARFT
*
END

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*> \brief \b DLARF
*
* =========== DOCUMENTATION ===========
*
* Online html documentation available at
* http://www.netlib.org/lapack/explore-html/
*
*> \htmlonly
*> Download DLARF + dependencies
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlarf.f">
*> [TGZ]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlarf.f">
*> [ZIP]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlarf.f">
*> [TXT]</a>
*> \endhtmlonly
*
* Definition:
* ===========
*
* SUBROUTINE DLARF( SIDE, M, N, V, INCV, TAU, C, LDC, WORK )
*
* .. Scalar Arguments ..
* CHARACTER SIDE
* INTEGER INCV, LDC, M, N
* DOUBLE PRECISION TAU
* ..
* .. Array Arguments ..
* DOUBLE PRECISION C( LDC, * ), V( * ), WORK( * )
* ..
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> DLARF applies a real elementary reflector H to a real m by n matrix
*> C, from either the left or the right. H is represented in the form
*>
*> H = I - tau * v * v**T
*>
*> where tau is a real scalar and v is a real vector.
*>
*> If tau = 0, then H is taken to be the unit matrix.
*> \endverbatim
*
* Arguments:
* ==========
*
*> \param[in] SIDE
*> \verbatim
*> SIDE is CHARACTER*1
*> = 'L': form H * C
*> = 'R': form C * H
*> \endverbatim
*>
*> \param[in] M
*> \verbatim
*> M is INTEGER
*> The number of rows of the matrix C.
*> \endverbatim
*>
*> \param[in] N
*> \verbatim
*> N is INTEGER
*> The number of columns of the matrix C.
*> \endverbatim
*>
*> \param[in] V
*> \verbatim
*> V is DOUBLE PRECISION array, dimension
*> (1 + (M-1)*abs(INCV)) if SIDE = 'L'
*> or (1 + (N-1)*abs(INCV)) if SIDE = 'R'
*> The vector v in the representation of H. V is not used if
*> TAU = 0.
*> \endverbatim
*>
*> \param[in] INCV
*> \verbatim
*> INCV is INTEGER
*> The increment between elements of v. INCV <> 0.
*> \endverbatim
*>
*> \param[in] TAU
*> \verbatim
*> TAU is DOUBLE PRECISION
*> The value tau in the representation of H.
*> \endverbatim
*>
*> \param[in,out] C
*> \verbatim
*> C is DOUBLE PRECISION array, dimension (LDC,N)
*> On entry, the m by n matrix C.
*> On exit, C is overwritten by the matrix H * C if SIDE = 'L',
*> or C * H if SIDE = 'R'.
*> \endverbatim
*>
*> \param[in] LDC
*> \verbatim
*> LDC is INTEGER
*> The leading dimension of the array C. LDC >= max(1,M).
*> \endverbatim
*>
*> \param[out] WORK
*> \verbatim
*> WORK is DOUBLE PRECISION array, dimension
*> (N) if SIDE = 'L'
*> or (M) if SIDE = 'R'
*> \endverbatim
*
* Authors:
* ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \date November 2011
*
*> \ingroup doubleOTHERauxiliary
*
* =====================================================================
SUBROUTINE DLARF( SIDE, M, N, V, INCV, TAU, C, LDC, WORK )
*
* -- LAPACK auxiliary routine (version 3.4.0) --
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
* November 2011
*
* .. Scalar Arguments ..
CHARACTER SIDE
INTEGER INCV, LDC, M, N
DOUBLE PRECISION TAU
* ..
* .. Array Arguments ..
DOUBLE PRECISION C( LDC, * ), V( * ), WORK( * )
* ..
*
* =====================================================================
*
* .. Parameters ..
DOUBLE PRECISION ONE, ZERO
PARAMETER ( ONE = 1.0D+0, ZERO = 0.0D+0 )
* ..
* .. Local Scalars ..
LOGICAL APPLYLEFT
INTEGER I, LASTV, LASTC
* ..
* .. External Subroutines ..
EXTERNAL DGEMV, DGER
* ..
* .. External Functions ..
LOGICAL LSAME
INTEGER ILADLR, ILADLC
EXTERNAL LSAME, ILADLR, ILADLC
* ..
* .. Executable Statements ..
*
APPLYLEFT = LSAME( SIDE, 'L' )
LASTV = 0
LASTC = 0
IF( TAU.NE.ZERO ) THEN
! Set up variables for scanning V. LASTV begins pointing to the end
! of V.
IF( APPLYLEFT ) THEN
LASTV = M
ELSE
LASTV = N
END IF
IF( INCV.GT.0 ) THEN
I = 1 + (LASTV-1) * INCV
ELSE
I = 1
END IF
! Look for the last non-zero row in V.
DO WHILE( LASTV.GT.0 .AND. V( I ).EQ.ZERO )
LASTV = LASTV - 1
I = I - INCV
END DO
IF( APPLYLEFT ) THEN
! Scan for the last non-zero column in C(1:lastv,:).
LASTC = ILADLC(LASTV, N, C, LDC)
ELSE
! Scan for the last non-zero row in C(:,1:lastv).
LASTC = ILADLR(M, LASTV, C, LDC)
END IF
END IF
! Note that lastc.eq.0 renders the BLAS operations null; no special
! case is needed at this level.
IF( APPLYLEFT ) THEN
*
* Form H * C
*
IF( LASTV.GT.0 ) THEN
*
* w(1:lastc,1) := C(1:lastv,1:lastc)**T * v(1:lastv,1)
*
CALL DGEMV( 'Transpose', LASTV, LASTC, ONE, C, LDC, V, INCV,
$ ZERO, WORK, 1 )
*
* C(1:lastv,1:lastc) := C(...) - v(1:lastv,1) * w(1:lastc,1)**T
*
CALL DGER( LASTV, LASTC, -TAU, V, INCV, WORK, 1, C, LDC )
END IF
ELSE
*
* Form C * H
*
IF( LASTV.GT.0 ) THEN
*
* w(1:lastc,1) := C(1:lastc,1:lastv) * v(1:lastv,1)
*
CALL DGEMV( 'No transpose', LASTC, LASTV, ONE, C, LDC,
$ V, INCV, ZERO, WORK, 1 )
*
* C(1:lastc,1:lastv) := C(...) - w(1:lastc,1) * v(1:lastv,1)**T
*
CALL DGER( LASTC, LASTV, -TAU, WORK, 1, V, INCV, C, LDC )
END IF
END IF
RETURN
*
* End of DLARF
*
END

762
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*> \brief \b DLARFB
*
* =========== DOCUMENTATION ===========
*
* Online html documentation available at
* http://www.netlib.org/lapack/explore-html/
*
*> \htmlonly
*> Download DLARFB + dependencies
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlarfb.f">
*> [TGZ]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlarfb.f">
*> [ZIP]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlarfb.f">
*> [TXT]</a>
*> \endhtmlonly
*
* Definition:
* ===========
*
* SUBROUTINE DLARFB( SIDE, TRANS, DIRECT, STOREV, M, N, K, V, LDV,
* T, LDT, C, LDC, WORK, LDWORK )
*
* .. Scalar Arguments ..
* CHARACTER DIRECT, SIDE, STOREV, TRANS
* INTEGER K, LDC, LDT, LDV, LDWORK, M, N
* ..
* .. Array Arguments ..
* DOUBLE PRECISION C( LDC, * ), T( LDT, * ), V( LDV, * ),
* $ WORK( LDWORK, * )
* ..
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> DLARFB applies a real block reflector H or its transpose H**T to a
*> real m by n matrix C, from either the left or the right.
*> \endverbatim
*
* Arguments:
* ==========
*
*> \param[in] SIDE
*> \verbatim
*> SIDE is CHARACTER*1
*> = 'L': apply H or H**T from the Left
*> = 'R': apply H or H**T from the Right
*> \endverbatim
*>
*> \param[in] TRANS
*> \verbatim
*> TRANS is CHARACTER*1
*> = 'N': apply H (No transpose)
*> = 'T': apply H**T (Transpose)
*> \endverbatim
*>
*> \param[in] DIRECT
*> \verbatim
*> DIRECT is CHARACTER*1
*> Indicates how H is formed from a product of elementary
*> reflectors
*> = 'F': H = H(1) H(2) . . . H(k) (Forward)
*> = 'B': H = H(k) . . . H(2) H(1) (Backward)
*> \endverbatim
*>
*> \param[in] STOREV
*> \verbatim
*> STOREV is CHARACTER*1
*> Indicates how the vectors which define the elementary
*> reflectors are stored:
*> = 'C': Columnwise
*> = 'R': Rowwise
*> \endverbatim
*>
*> \param[in] M
*> \verbatim
*> M is INTEGER
*> The number of rows of the matrix C.
*> \endverbatim
*>
*> \param[in] N
*> \verbatim
*> N is INTEGER
*> The number of columns of the matrix C.
*> \endverbatim
*>
*> \param[in] K
*> \verbatim
*> K is INTEGER
*> The order of the matrix T (= the number of elementary
*> reflectors whose product defines the block reflector).
*> \endverbatim
*>
*> \param[in] V
*> \verbatim
*> V is DOUBLE PRECISION array, dimension
*> (LDV,K) if STOREV = 'C'
*> (LDV,M) if STOREV = 'R' and SIDE = 'L'
*> (LDV,N) if STOREV = 'R' and SIDE = 'R'
*> The matrix V. See Further Details.
*> \endverbatim
*>
*> \param[in] LDV
*> \verbatim
*> LDV is INTEGER
*> The leading dimension of the array V.
*> If STOREV = 'C' and SIDE = 'L', LDV >= max(1,M);
*> if STOREV = 'C' and SIDE = 'R', LDV >= max(1,N);
*> if STOREV = 'R', LDV >= K.
*> \endverbatim
*>
*> \param[in] T
*> \verbatim
*> T is DOUBLE PRECISION array, dimension (LDT,K)
*> The triangular k by k matrix T in the representation of the
*> block reflector.
*> \endverbatim
*>
*> \param[in] LDT
*> \verbatim
*> LDT is INTEGER
*> The leading dimension of the array T. LDT >= K.
*> \endverbatim
*>
*> \param[in,out] C
*> \verbatim
*> C is DOUBLE PRECISION array, dimension (LDC,N)
*> On entry, the m by n matrix C.
*> On exit, C is overwritten by H*C or H**T*C or C*H or C*H**T.
*> \endverbatim
*>
*> \param[in] LDC
*> \verbatim
*> LDC is INTEGER
*> The leading dimension of the array C. LDC >= max(1,M).
*> \endverbatim
*>
*> \param[out] WORK
*> \verbatim
*> WORK is DOUBLE PRECISION array, dimension (LDWORK,K)
*> \endverbatim
*>
*> \param[in] LDWORK
*> \verbatim
*> LDWORK is INTEGER
*> The leading dimension of the array WORK.
*> If SIDE = 'L', LDWORK >= max(1,N);
*> if SIDE = 'R', LDWORK >= max(1,M).
*> \endverbatim
*
* Authors:
* ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \date November 2011
*
*> \ingroup doubleOTHERauxiliary
*
*> \par Further Details:
* =====================
*>
*> \verbatim
*>
*> The shape of the matrix V and the storage of the vectors which define
*> the H(i) is best illustrated by the following example with n = 5 and
*> k = 3. The elements equal to 1 are not stored; the corresponding
*> array elements are modified but restored on exit. The rest of the
*> array is not used.
*>
*> DIRECT = 'F' and STOREV = 'C': DIRECT = 'F' and STOREV = 'R':
*>
*> V = ( 1 ) V = ( 1 v1 v1 v1 v1 )
*> ( v1 1 ) ( 1 v2 v2 v2 )
*> ( v1 v2 1 ) ( 1 v3 v3 )
*> ( v1 v2 v3 )
*> ( v1 v2 v3 )
*>
*> DIRECT = 'B' and STOREV = 'C': DIRECT = 'B' and STOREV = 'R':
*>
*> V = ( v1 v2 v3 ) V = ( v1 v1 1 )
*> ( v1 v2 v3 ) ( v2 v2 v2 1 )
*> ( 1 v2 v3 ) ( v3 v3 v3 v3 1 )
*> ( 1 v3 )
*> ( 1 )
*> \endverbatim
*>
* =====================================================================
SUBROUTINE DLARFB( SIDE, TRANS, DIRECT, STOREV, M, N, K, V, LDV,
$ T, LDT, C, LDC, WORK, LDWORK )
*
* -- LAPACK auxiliary routine (version 3.4.0) --
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
* November 2011
*
* .. Scalar Arguments ..
CHARACTER DIRECT, SIDE, STOREV, TRANS
INTEGER K, LDC, LDT, LDV, LDWORK, M, N
* ..
* .. Array Arguments ..
DOUBLE PRECISION C( LDC, * ), T( LDT, * ), V( LDV, * ),
$ WORK( LDWORK, * )
* ..
*
* =====================================================================
*
* .. Parameters ..
DOUBLE PRECISION ONE
PARAMETER ( ONE = 1.0D+0 )
* ..
* .. Local Scalars ..
CHARACTER TRANST
INTEGER I, J, LASTV, LASTC
* ..
* .. External Functions ..
LOGICAL LSAME
INTEGER ILADLR, ILADLC
EXTERNAL LSAME, ILADLR, ILADLC
* ..
* .. External Subroutines ..
EXTERNAL DCOPY, DGEMM, DTRMM
* ..
* .. Executable Statements ..
*
* Quick return if possible
*
IF( M.LE.0 .OR. N.LE.0 )
$ RETURN
*
IF( LSAME( TRANS, 'N' ) ) THEN
TRANST = 'T'
ELSE
TRANST = 'N'
END IF
*
IF( LSAME( STOREV, 'C' ) ) THEN
*
IF( LSAME( DIRECT, 'F' ) ) THEN
*
* Let V = ( V1 ) (first K rows)
* ( V2 )
* where V1 is unit lower triangular.
*
IF( LSAME( SIDE, 'L' ) ) THEN
*
* Form H * C or H**T * C where C = ( C1 )
* ( C2 )
*
LASTV = MAX( K, ILADLR( M, K, V, LDV ) )
LASTC = ILADLC( LASTV, N, C, LDC )
*
* W := C**T * V = (C1**T * V1 + C2**T * V2) (stored in WORK)
*
* W := C1**T
*
DO 10 J = 1, K
CALL DCOPY( LASTC, C( J, 1 ), LDC, WORK( 1, J ), 1 )
10 CONTINUE
*
* W := W * V1
*
CALL DTRMM( 'Right', 'Lower', 'No transpose', 'Unit',
$ LASTC, K, ONE, V, LDV, WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C2**T *V2
*
CALL DGEMM( 'Transpose', 'No transpose',
$ LASTC, K, LASTV-K,
$ ONE, C( K+1, 1 ), LDC, V( K+1, 1 ), LDV,
$ ONE, WORK, LDWORK )
END IF
*
* W := W * T**T or W * T
*
CALL DTRMM( 'Right', 'Upper', TRANST, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - V * W**T
*
IF( LASTV.GT.K ) THEN
*
* C2 := C2 - V2 * W**T
*
CALL DGEMM( 'No transpose', 'Transpose',
$ LASTV-K, LASTC, K,
$ -ONE, V( K+1, 1 ), LDV, WORK, LDWORK, ONE,
$ C( K+1, 1 ), LDC )
END IF
*
* W := W * V1**T
*
CALL DTRMM( 'Right', 'Lower', 'Transpose', 'Unit',
$ LASTC, K, ONE, V, LDV, WORK, LDWORK )
*
* C1 := C1 - W**T
*
DO 30 J = 1, K
DO 20 I = 1, LASTC
C( J, I ) = C( J, I ) - WORK( I, J )
20 CONTINUE
30 CONTINUE
*
ELSE IF( LSAME( SIDE, 'R' ) ) THEN
*
* Form C * H or C * H**T where C = ( C1 C2 )
*
LASTV = MAX( K, ILADLR( N, K, V, LDV ) )
LASTC = ILADLR( M, LASTV, C, LDC )
*
* W := C * V = (C1*V1 + C2*V2) (stored in WORK)
*
* W := C1
*
DO 40 J = 1, K
CALL DCOPY( LASTC, C( 1, J ), 1, WORK( 1, J ), 1 )
40 CONTINUE
*
* W := W * V1
*
CALL DTRMM( 'Right', 'Lower', 'No transpose', 'Unit',
$ LASTC, K, ONE, V, LDV, WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C2 * V2
*
CALL DGEMM( 'No transpose', 'No transpose',
$ LASTC, K, LASTV-K,
$ ONE, C( 1, K+1 ), LDC, V( K+1, 1 ), LDV,
$ ONE, WORK, LDWORK )
END IF
*
* W := W * T or W * T**T
*
CALL DTRMM( 'Right', 'Upper', TRANS, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - W * V**T
*
IF( LASTV.GT.K ) THEN
*
* C2 := C2 - W * V2**T
*
CALL DGEMM( 'No transpose', 'Transpose',
$ LASTC, LASTV-K, K,
$ -ONE, WORK, LDWORK, V( K+1, 1 ), LDV, ONE,
$ C( 1, K+1 ), LDC )
END IF
*
* W := W * V1**T
*
CALL DTRMM( 'Right', 'Lower', 'Transpose', 'Unit',
$ LASTC, K, ONE, V, LDV, WORK, LDWORK )
*
* C1 := C1 - W
*
DO 60 J = 1, K
DO 50 I = 1, LASTC
C( I, J ) = C( I, J ) - WORK( I, J )
50 CONTINUE
60 CONTINUE
END IF
*
ELSE
*
* Let V = ( V1 )
* ( V2 ) (last K rows)
* where V2 is unit upper triangular.
*
IF( LSAME( SIDE, 'L' ) ) THEN
*
* Form H * C or H**T * C where C = ( C1 )
* ( C2 )
*
LASTV = MAX( K, ILADLR( M, K, V, LDV ) )
LASTC = ILADLC( LASTV, N, C, LDC )
*
* W := C**T * V = (C1**T * V1 + C2**T * V2) (stored in WORK)
*
* W := C2**T
*
DO 70 J = 1, K
CALL DCOPY( LASTC, C( LASTV-K+J, 1 ), LDC,
$ WORK( 1, J ), 1 )
70 CONTINUE
*
* W := W * V2
*
CALL DTRMM( 'Right', 'Upper', 'No transpose', 'Unit',
$ LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
$ WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C1**T*V1
*
CALL DGEMM( 'Transpose', 'No transpose',
$ LASTC, K, LASTV-K, ONE, C, LDC, V, LDV,
$ ONE, WORK, LDWORK )
END IF
*
* W := W * T**T or W * T
*
CALL DTRMM( 'Right', 'Lower', TRANST, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - V * W**T
*
IF( LASTV.GT.K ) THEN
*
* C1 := C1 - V1 * W**T
*
CALL DGEMM( 'No transpose', 'Transpose',
$ LASTV-K, LASTC, K, -ONE, V, LDV, WORK, LDWORK,
$ ONE, C, LDC )
END IF
*
* W := W * V2**T
*
CALL DTRMM( 'Right', 'Upper', 'Transpose', 'Unit',
$ LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
$ WORK, LDWORK )
*
* C2 := C2 - W**T
*
DO 90 J = 1, K
DO 80 I = 1, LASTC
C( LASTV-K+J, I ) = C( LASTV-K+J, I ) - WORK(I, J)
80 CONTINUE
90 CONTINUE
*
ELSE IF( LSAME( SIDE, 'R' ) ) THEN
*
* Form C * H or C * H**T where C = ( C1 C2 )
*
LASTV = MAX( K, ILADLR( N, K, V, LDV ) )
LASTC = ILADLR( M, LASTV, C, LDC )
*
* W := C * V = (C1*V1 + C2*V2) (stored in WORK)
*
* W := C2
*
DO 100 J = 1, K
CALL DCOPY( LASTC, C( 1, N-K+J ), 1, WORK( 1, J ), 1 )
100 CONTINUE
*
* W := W * V2
*
CALL DTRMM( 'Right', 'Upper', 'No transpose', 'Unit',
$ LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
$ WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C1 * V1
*
CALL DGEMM( 'No transpose', 'No transpose',
$ LASTC, K, LASTV-K, ONE, C, LDC, V, LDV,
$ ONE, WORK, LDWORK )
END IF
*
* W := W * T or W * T**T
*
CALL DTRMM( 'Right', 'Lower', TRANS, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - W * V**T
*
IF( LASTV.GT.K ) THEN
*
* C1 := C1 - W * V1**T
*
CALL DGEMM( 'No transpose', 'Transpose',
$ LASTC, LASTV-K, K, -ONE, WORK, LDWORK, V, LDV,
$ ONE, C, LDC )
END IF
*
* W := W * V2**T
*
CALL DTRMM( 'Right', 'Upper', 'Transpose', 'Unit',
$ LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
$ WORK, LDWORK )
*
* C2 := C2 - W
*
DO 120 J = 1, K
DO 110 I = 1, LASTC
C( I, LASTV-K+J ) = C( I, LASTV-K+J ) - WORK(I, J)
110 CONTINUE
120 CONTINUE
END IF
END IF
*
ELSE IF( LSAME( STOREV, 'R' ) ) THEN
*
IF( LSAME( DIRECT, 'F' ) ) THEN
*
* Let V = ( V1 V2 ) (V1: first K columns)
* where V1 is unit upper triangular.
*
IF( LSAME( SIDE, 'L' ) ) THEN
*
* Form H * C or H**T * C where C = ( C1 )
* ( C2 )
*
LASTV = MAX( K, ILADLC( K, M, V, LDV ) )
LASTC = ILADLC( LASTV, N, C, LDC )
*
* W := C**T * V**T = (C1**T * V1**T + C2**T * V2**T) (stored in WORK)
*
* W := C1**T
*
DO 130 J = 1, K
CALL DCOPY( LASTC, C( J, 1 ), LDC, WORK( 1, J ), 1 )
130 CONTINUE
*
* W := W * V1**T
*
CALL DTRMM( 'Right', 'Upper', 'Transpose', 'Unit',
$ LASTC, K, ONE, V, LDV, WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C2**T*V2**T
*
CALL DGEMM( 'Transpose', 'Transpose',
$ LASTC, K, LASTV-K,
$ ONE, C( K+1, 1 ), LDC, V( 1, K+1 ), LDV,
$ ONE, WORK, LDWORK )
END IF
*
* W := W * T**T or W * T
*
CALL DTRMM( 'Right', 'Upper', TRANST, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - V**T * W**T
*
IF( LASTV.GT.K ) THEN
*
* C2 := C2 - V2**T * W**T
*
CALL DGEMM( 'Transpose', 'Transpose',
$ LASTV-K, LASTC, K,
$ -ONE, V( 1, K+1 ), LDV, WORK, LDWORK,
$ ONE, C( K+1, 1 ), LDC )
END IF
*
* W := W * V1
*
CALL DTRMM( 'Right', 'Upper', 'No transpose', 'Unit',
$ LASTC, K, ONE, V, LDV, WORK, LDWORK )
*
* C1 := C1 - W**T
*
DO 150 J = 1, K
DO 140 I = 1, LASTC
C( J, I ) = C( J, I ) - WORK( I, J )
140 CONTINUE
150 CONTINUE
*
ELSE IF( LSAME( SIDE, 'R' ) ) THEN
*
* Form C * H or C * H**T where C = ( C1 C2 )
*
LASTV = MAX( K, ILADLC( K, N, V, LDV ) )
LASTC = ILADLR( M, LASTV, C, LDC )
*
* W := C * V**T = (C1*V1**T + C2*V2**T) (stored in WORK)
*
* W := C1
*
DO 160 J = 1, K
CALL DCOPY( LASTC, C( 1, J ), 1, WORK( 1, J ), 1 )
160 CONTINUE
*
* W := W * V1**T
*
CALL DTRMM( 'Right', 'Upper', 'Transpose', 'Unit',
$ LASTC, K, ONE, V, LDV, WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C2 * V2**T
*
CALL DGEMM( 'No transpose', 'Transpose',
$ LASTC, K, LASTV-K,
$ ONE, C( 1, K+1 ), LDC, V( 1, K+1 ), LDV,
$ ONE, WORK, LDWORK )
END IF
*
* W := W * T or W * T**T
*
CALL DTRMM( 'Right', 'Upper', TRANS, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - W * V
*
IF( LASTV.GT.K ) THEN
*
* C2 := C2 - W * V2
*
CALL DGEMM( 'No transpose', 'No transpose',
$ LASTC, LASTV-K, K,
$ -ONE, WORK, LDWORK, V( 1, K+1 ), LDV,
$ ONE, C( 1, K+1 ), LDC )
END IF
*
* W := W * V1
*
CALL DTRMM( 'Right', 'Upper', 'No transpose', 'Unit',
$ LASTC, K, ONE, V, LDV, WORK, LDWORK )
*
* C1 := C1 - W
*
DO 180 J = 1, K
DO 170 I = 1, LASTC
C( I, J ) = C( I, J ) - WORK( I, J )
170 CONTINUE
180 CONTINUE
*
END IF
*
ELSE
*
* Let V = ( V1 V2 ) (V2: last K columns)
* where V2 is unit lower triangular.
*
IF( LSAME( SIDE, 'L' ) ) THEN
*
* Form H * C or H**T * C where C = ( C1 )
* ( C2 )
*
LASTV = MAX( K, ILADLC( K, M, V, LDV ) )
LASTC = ILADLC( LASTV, N, C, LDC )
*
* W := C**T * V**T = (C1**T * V1**T + C2**T * V2**T) (stored in WORK)
*
* W := C2**T
*
DO 190 J = 1, K
CALL DCOPY( LASTC, C( LASTV-K+J, 1 ), LDC,
$ WORK( 1, J ), 1 )
190 CONTINUE
*
* W := W * V2**T
*
CALL DTRMM( 'Right', 'Lower', 'Transpose', 'Unit',
$ LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV,
$ WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C1**T * V1**T
*
CALL DGEMM( 'Transpose', 'Transpose',
$ LASTC, K, LASTV-K, ONE, C, LDC, V, LDV,
$ ONE, WORK, LDWORK )
END IF
*
* W := W * T**T or W * T
*
CALL DTRMM( 'Right', 'Lower', TRANST, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - V**T * W**T
*
IF( LASTV.GT.K ) THEN
*
* C1 := C1 - V1**T * W**T
*
CALL DGEMM( 'Transpose', 'Transpose',
$ LASTV-K, LASTC, K, -ONE, V, LDV, WORK, LDWORK,
$ ONE, C, LDC )
END IF
*
* W := W * V2
*
CALL DTRMM( 'Right', 'Lower', 'No transpose', 'Unit',
$ LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV,
$ WORK, LDWORK )
*
* C2 := C2 - W**T
*
DO 210 J = 1, K
DO 200 I = 1, LASTC
C( LASTV-K+J, I ) = C( LASTV-K+J, I ) - WORK(I, J)
200 CONTINUE
210 CONTINUE
*
ELSE IF( LSAME( SIDE, 'R' ) ) THEN
*
* Form C * H or C * H**T where C = ( C1 C2 )
*
LASTV = MAX( K, ILADLC( K, N, V, LDV ) )
LASTC = ILADLR( M, LASTV, C, LDC )
*
* W := C * V**T = (C1*V1**T + C2*V2**T) (stored in WORK)
*
* W := C2
*
DO 220 J = 1, K
CALL DCOPY( LASTC, C( 1, LASTV-K+J ), 1,
$ WORK( 1, J ), 1 )
220 CONTINUE
*
* W := W * V2**T
*
CALL DTRMM( 'Right', 'Lower', 'Transpose', 'Unit',
$ LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV,
$ WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C1 * V1**T
*
CALL DGEMM( 'No transpose', 'Transpose',
$ LASTC, K, LASTV-K, ONE, C, LDC, V, LDV,
$ ONE, WORK, LDWORK )
END IF
*
* W := W * T or W * T**T
*
CALL DTRMM( 'Right', 'Lower', TRANS, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - W * V
*
IF( LASTV.GT.K ) THEN
*
* C1 := C1 - W * V1
*
CALL DGEMM( 'No transpose', 'No transpose',
$ LASTC, LASTV-K, K, -ONE, WORK, LDWORK, V, LDV,
$ ONE, C, LDC )
END IF
*
* W := W * V2
*
CALL DTRMM( 'Right', 'Lower', 'No transpose', 'Unit',
$ LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV,
$ WORK, LDWORK )
*
* C1 := C1 - W
*
DO 240 J = 1, K
DO 230 I = 1, LASTC
C( I, LASTV-K+J ) = C( I, LASTV-K+J ) - WORK(I, J)
230 CONTINUE
240 CONTINUE
*
END IF
*
END IF
END IF
*
RETURN
*
* End of DLARFB
*
END

196
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*> \brief \b DLARFG
*
* =========== DOCUMENTATION ===========
*
* Online html documentation available at
* http://www.netlib.org/lapack/explore-html/
*
*> \htmlonly
*> Download DLARFG + dependencies
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlarfg.f">
*> [TGZ]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlarfg.f">
*> [ZIP]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlarfg.f">
*> [TXT]</a>
*> \endhtmlonly
*
* Definition:
* ===========
*
* SUBROUTINE DLARFG( N, ALPHA, X, INCX, TAU )
*
* .. Scalar Arguments ..
* INTEGER INCX, N
* DOUBLE PRECISION ALPHA, TAU
* ..
* .. Array Arguments ..
* DOUBLE PRECISION X( * )
* ..
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> DLARFG generates a real elementary reflector H of order n, such
*> that
*>
*> H * ( alpha ) = ( beta ), H**T * H = I.
*> ( x ) ( 0 )
*>
*> where alpha and beta are scalars, and x is an (n-1)-element real
*> vector. H is represented in the form
*>
*> H = I - tau * ( 1 ) * ( 1 v**T ) ,
*> ( v )
*>
*> where tau is a real scalar and v is a real (n-1)-element
*> vector.
*>
*> If the elements of x are all zero, then tau = 0 and H is taken to be
*> the unit matrix.
*>
*> Otherwise 1 <= tau <= 2.
*> \endverbatim
*
* Arguments:
* ==========
*
*> \param[in] N
*> \verbatim
*> N is INTEGER
*> The order of the elementary reflector.
*> \endverbatim
*>
*> \param[in,out] ALPHA
*> \verbatim
*> ALPHA is DOUBLE PRECISION
*> On entry, the value alpha.
*> On exit, it is overwritten with the value beta.
*> \endverbatim
*>
*> \param[in,out] X
*> \verbatim
*> X is DOUBLE PRECISION array, dimension
*> (1+(N-2)*abs(INCX))
*> On entry, the vector x.
*> On exit, it is overwritten with the vector v.
*> \endverbatim
*>
*> \param[in] INCX
*> \verbatim
*> INCX is INTEGER
*> The increment between elements of X. INCX > 0.
*> \endverbatim
*>
*> \param[out] TAU
*> \verbatim
*> TAU is DOUBLE PRECISION
*> The value tau.
*> \endverbatim
*
* Authors:
* ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \date November 2011
*
*> \ingroup doubleOTHERauxiliary
*
* =====================================================================
SUBROUTINE DLARFG( N, ALPHA, X, INCX, TAU )
*
* -- LAPACK auxiliary routine (version 3.4.0) --
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
* November 2011
*
* .. Scalar Arguments ..
INTEGER INCX, N
DOUBLE PRECISION ALPHA, TAU
* ..
* .. Array Arguments ..
DOUBLE PRECISION X( * )
* ..
*
* =====================================================================
*
* .. Parameters ..
DOUBLE PRECISION ONE, ZERO
PARAMETER ( ONE = 1.0D+0, ZERO = 0.0D+0 )
* ..
* .. Local Scalars ..
INTEGER J, KNT
DOUBLE PRECISION BETA, RSAFMN, SAFMIN, XNORM
* ..
* .. External Functions ..
DOUBLE PRECISION DLAMCH, DLAPY2, DNRM2
EXTERNAL DLAMCH, DLAPY2, DNRM2
* ..
* .. Intrinsic Functions ..
INTRINSIC ABS, SIGN
* ..
* .. External Subroutines ..
EXTERNAL DSCAL
* ..
* .. Executable Statements ..
*
IF( N.LE.1 ) THEN
TAU = ZERO
RETURN
END IF
*
XNORM = DNRM2( N-1, X, INCX )
*
IF( XNORM.EQ.ZERO ) THEN
*
* H = I
*
TAU = ZERO
ELSE
*
* general case
*
BETA = -SIGN( DLAPY2( ALPHA, XNORM ), ALPHA )
SAFMIN = DLAMCH( 'S' ) / DLAMCH( 'E' )
KNT = 0
IF( ABS( BETA ).LT.SAFMIN ) THEN
*
* XNORM, BETA may be inaccurate; scale X and recompute them
*
RSAFMN = ONE / SAFMIN
10 CONTINUE
KNT = KNT + 1
CALL DSCAL( N-1, RSAFMN, X, INCX )
BETA = BETA*RSAFMN
ALPHA = ALPHA*RSAFMN
IF( ABS( BETA ).LT.SAFMIN )
$ GO TO 10
*
* New BETA is at most 1, at least SAFMIN
*
XNORM = DNRM2( N-1, X, INCX )
BETA = -SIGN( DLAPY2( ALPHA, XNORM ), ALPHA )
END IF
TAU = ( BETA-ALPHA ) / BETA
CALL DSCAL( N-1, ONE / ( ALPHA-BETA ), X, INCX )
*
* If ALPHA is subnormal, it may lose relative accuracy
*
DO 20 J = 1, KNT
BETA = BETA*SAFMIN
20 CONTINUE
ALPHA = BETA
END IF
*
RETURN
*
* End of DLARFG
*
END

326
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*> \brief \b DLARFT
*
* =========== DOCUMENTATION ===========
*
* Online html documentation available at
* http://www.netlib.org/lapack/explore-html/
*
*> \htmlonly
*> Download DLARFT + dependencies
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlarft.f">
*> [TGZ]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlarft.f">
*> [ZIP]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlarft.f">
*> [TXT]</a>
*> \endhtmlonly
*
* Definition:
* ===========
*
* SUBROUTINE DLARFT( DIRECT, STOREV, N, K, V, LDV, TAU, T, LDT )
*
* .. Scalar Arguments ..
* CHARACTER DIRECT, STOREV
* INTEGER K, LDT, LDV, N
* ..
* .. Array Arguments ..
* DOUBLE PRECISION T( LDT, * ), TAU( * ), V( LDV, * )
* ..
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> DLARFT forms the triangular factor T of a real block reflector H
*> of order n, which is defined as a product of k elementary reflectors.
*>
*> If DIRECT = 'F', H = H(1) H(2) . . . H(k) and T is upper triangular;
*>
*> If DIRECT = 'B', H = H(k) . . . H(2) H(1) and T is lower triangular.
*>
*> If STOREV = 'C', the vector which defines the elementary reflector
*> H(i) is stored in the i-th column of the array V, and
*>
*> H = I - V * T * V**T
*>
*> If STOREV = 'R', the vector which defines the elementary reflector
*> H(i) is stored in the i-th row of the array V, and
*>
*> H = I - V**T * T * V
*> \endverbatim
*
* Arguments:
* ==========
*
*> \param[in] DIRECT
*> \verbatim
*> DIRECT is CHARACTER*1
*> Specifies the order in which the elementary reflectors are
*> multiplied to form the block reflector:
*> = 'F': H = H(1) H(2) . . . H(k) (Forward)
*> = 'B': H = H(k) . . . H(2) H(1) (Backward)
*> \endverbatim
*>
*> \param[in] STOREV
*> \verbatim
*> STOREV is CHARACTER*1
*> Specifies how the vectors which define the elementary
*> reflectors are stored (see also Further Details):
*> = 'C': columnwise
*> = 'R': rowwise
*> \endverbatim
*>
*> \param[in] N
*> \verbatim
*> N is INTEGER
*> The order of the block reflector H. N >= 0.
*> \endverbatim
*>
*> \param[in] K
*> \verbatim
*> K is INTEGER
*> The order of the triangular factor T (= the number of
*> elementary reflectors). K >= 1.
*> \endverbatim
*>
*> \param[in] V
*> \verbatim
*> V is DOUBLE PRECISION array, dimension
*> (LDV,K) if STOREV = 'C'
*> (LDV,N) if STOREV = 'R'
*> The matrix V. See further details.
*> \endverbatim
*>
*> \param[in] LDV
*> \verbatim
*> LDV is INTEGER
*> The leading dimension of the array V.
*> If STOREV = 'C', LDV >= max(1,N); if STOREV = 'R', LDV >= K.
*> \endverbatim
*>
*> \param[in] TAU
*> \verbatim
*> TAU is DOUBLE PRECISION array, dimension (K)
*> TAU(i) must contain the scalar factor of the elementary
*> reflector H(i).
*> \endverbatim
*>
*> \param[out] T
*> \verbatim
*> T is DOUBLE PRECISION array, dimension (LDT,K)
*> The k by k triangular factor T of the block reflector.
*> If DIRECT = 'F', T is upper triangular; if DIRECT = 'B', T is
*> lower triangular. The rest of the array is not used.
*> \endverbatim
*>
*> \param[in] LDT
*> \verbatim
*> LDT is INTEGER
*> The leading dimension of the array T. LDT >= K.
*> \endverbatim
*
* Authors:
* ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \date April 2012
*
*> \ingroup doubleOTHERauxiliary
*
*> \par Further Details:
* =====================
*>
*> \verbatim
*>
*> The shape of the matrix V and the storage of the vectors which define
*> the H(i) is best illustrated by the following example with n = 5 and
*> k = 3. The elements equal to 1 are not stored.
*>
*> DIRECT = 'F' and STOREV = 'C': DIRECT = 'F' and STOREV = 'R':
*>
*> V = ( 1 ) V = ( 1 v1 v1 v1 v1 )
*> ( v1 1 ) ( 1 v2 v2 v2 )
*> ( v1 v2 1 ) ( 1 v3 v3 )
*> ( v1 v2 v3 )
*> ( v1 v2 v3 )
*>
*> DIRECT = 'B' and STOREV = 'C': DIRECT = 'B' and STOREV = 'R':
*>
*> V = ( v1 v2 v3 ) V = ( v1 v1 1 )
*> ( v1 v2 v3 ) ( v2 v2 v2 1 )
*> ( 1 v2 v3 ) ( v3 v3 v3 v3 1 )
*> ( 1 v3 )
*> ( 1 )
*> \endverbatim
*>
* =====================================================================
SUBROUTINE DLARFT( DIRECT, STOREV, N, K, V, LDV, TAU, T, LDT )
*
* -- LAPACK auxiliary routine (version 3.4.1) --
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
* April 2012
*
* .. Scalar Arguments ..
CHARACTER DIRECT, STOREV
INTEGER K, LDT, LDV, N
* ..
* .. Array Arguments ..
DOUBLE PRECISION T( LDT, * ), TAU( * ), V( LDV, * )
* ..
*
* =====================================================================
*
* .. Parameters ..
DOUBLE PRECISION ONE, ZERO
PARAMETER ( ONE = 1.0D+0, ZERO = 0.0D+0 )
* ..
* .. Local Scalars ..
INTEGER I, J, PREVLASTV, LASTV
* ..
* .. External Subroutines ..
EXTERNAL DGEMV, DTRMV
* ..
* .. External Functions ..
LOGICAL LSAME
EXTERNAL LSAME
* ..
* .. Executable Statements ..
*
* Quick return if possible
*
IF( N.EQ.0 )
$ RETURN
*
IF( LSAME( DIRECT, 'F' ) ) THEN
PREVLASTV = N
DO I = 1, K
PREVLASTV = MAX( I, PREVLASTV )
IF( TAU( I ).EQ.ZERO ) THEN
*
* H(i) = I
*
DO J = 1, I
T( J, I ) = ZERO
END DO
ELSE
*
* general case
*
IF( LSAME( STOREV, 'C' ) ) THEN
* Skip any trailing zeros.
DO LASTV = N, I+1, -1
IF( V( LASTV, I ).NE.ZERO ) EXIT
END DO
DO J = 1, I-1
T( J, I ) = -TAU( I ) * V( I , J )
END DO
J = MIN( LASTV, PREVLASTV )
*
* T(1:i-1,i) := - tau(i) * V(i:j,1:i-1)**T * V(i:j,i)
*
CALL DGEMV( 'Transpose', J-I, I-1, -TAU( I ),
$ V( I+1, 1 ), LDV, V( I+1, I ), 1, ONE,
$ T( 1, I ), 1 )
ELSE
* Skip any trailing zeros.
DO LASTV = N, I+1, -1
IF( V( I, LASTV ).NE.ZERO ) EXIT
END DO
DO J = 1, I-1
T( J, I ) = -TAU( I ) * V( J , I )
END DO
J = MIN( LASTV, PREVLASTV )
*
* T(1:i-1,i) := - tau(i) * V(1:i-1,i:j) * V(i,i:j)**T
*
CALL DGEMV( 'No transpose', I-1, J-I, -TAU( I ),
$ V( 1, I+1 ), LDV, V( I, I+1 ), LDV, ONE,
$ T( 1, I ), 1 )
END IF
*
* T(1:i-1,i) := T(1:i-1,1:i-1) * T(1:i-1,i)
*
CALL DTRMV( 'Upper', 'No transpose', 'Non-unit', I-1, T,
$ LDT, T( 1, I ), 1 )
T( I, I ) = TAU( I )
IF( I.GT.1 ) THEN
PREVLASTV = MAX( PREVLASTV, LASTV )
ELSE
PREVLASTV = LASTV
END IF
END IF
END DO
ELSE
PREVLASTV = 1
DO I = K, 1, -1
IF( TAU( I ).EQ.ZERO ) THEN
*
* H(i) = I
*
DO J = I, K
T( J, I ) = ZERO
END DO
ELSE
*
* general case
*
IF( I.LT.K ) THEN
IF( LSAME( STOREV, 'C' ) ) THEN
* Skip any leading zeros.
DO LASTV = 1, I-1
IF( V( LASTV, I ).NE.ZERO ) EXIT
END DO
DO J = I+1, K
T( J, I ) = -TAU( I ) * V( N-K+I , J )
END DO
J = MAX( LASTV, PREVLASTV )
*
* T(i+1:k,i) = -tau(i) * V(j:n-k+i,i+1:k)**T * V(j:n-k+i,i)
*
CALL DGEMV( 'Transpose', N-K+I-J, K-I, -TAU( I ),
$ V( J, I+1 ), LDV, V( J, I ), 1, ONE,
$ T( I+1, I ), 1 )
ELSE
* Skip any leading zeros.
DO LASTV = 1, I-1
IF( V( I, LASTV ).NE.ZERO ) EXIT
END DO
DO J = I+1, K
T( J, I ) = -TAU( I ) * V( J, N-K+I )
END DO
J = MAX( LASTV, PREVLASTV )
*
* T(i+1:k,i) = -tau(i) * V(i+1:k,j:n-k+i) * V(i,j:n-k+i)**T
*
CALL DGEMV( 'No transpose', K-I, N-K+I-J,
$ -TAU( I ), V( I+1, J ), LDV, V( I, J ), LDV,
$ ONE, T( I+1, I ), 1 )
END IF
*
* T(i+1:k,i) := T(i+1:k,i+1:k) * T(i+1:k,i)
*
CALL DTRMV( 'Lower', 'No transpose', 'Non-unit', K-I,
$ T( I+1, I+1 ), LDT, T( I+1, I ), 1 )
IF( I.GT.1 ) THEN
PREVLASTV = MIN( PREVLASTV, LASTV )
ELSE
PREVLASTV = LASTV
END IF
END IF
T( I, I ) = TAU( I )
END IF
END DO
END IF
RETURN
*
* End of DLARFT
*
END

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*> \brief \b SLARF
*
* =========== DOCUMENTATION ===========
*
* Online html documentation available at
* http://www.netlib.org/lapack/explore-html/
*
*> \htmlonly
*> Download SLARF + dependencies
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/slarf.f">
*> [TGZ]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/slarf.f">
*> [ZIP]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/slarf.f">
*> [TXT]</a>
*> \endhtmlonly
*
* Definition:
* ===========
*
* SUBROUTINE SLARF( SIDE, M, N, V, INCV, TAU, C, LDC, WORK )
*
* .. Scalar Arguments ..
* CHARACTER SIDE
* INTEGER INCV, LDC, M, N
* REAL TAU
* ..
* .. Array Arguments ..
* REAL C( LDC, * ), V( * ), WORK( * )
* ..
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> SLARF applies a real elementary reflector H to a real m by n matrix
*> C, from either the left or the right. H is represented in the form
*>
*> H = I - tau * v * v**T
*>
*> where tau is a real scalar and v is a real vector.
*>
*> If tau = 0, then H is taken to be the unit matrix.
*> \endverbatim
*
* Arguments:
* ==========
*
*> \param[in] SIDE
*> \verbatim
*> SIDE is CHARACTER*1
*> = 'L': form H * C
*> = 'R': form C * H
*> \endverbatim
*>
*> \param[in] M
*> \verbatim
*> M is INTEGER
*> The number of rows of the matrix C.
*> \endverbatim
*>
*> \param[in] N
*> \verbatim
*> N is INTEGER
*> The number of columns of the matrix C.
*> \endverbatim
*>
*> \param[in] V
*> \verbatim
*> V is REAL array, dimension
*> (1 + (M-1)*abs(INCV)) if SIDE = 'L'
*> or (1 + (N-1)*abs(INCV)) if SIDE = 'R'
*> The vector v in the representation of H. V is not used if
*> TAU = 0.
*> \endverbatim
*>
*> \param[in] INCV
*> \verbatim
*> INCV is INTEGER
*> The increment between elements of v. INCV <> 0.
*> \endverbatim
*>
*> \param[in] TAU
*> \verbatim
*> TAU is REAL
*> The value tau in the representation of H.
*> \endverbatim
*>
*> \param[in,out] C
*> \verbatim
*> C is REAL array, dimension (LDC,N)
*> On entry, the m by n matrix C.
*> On exit, C is overwritten by the matrix H * C if SIDE = 'L',
*> or C * H if SIDE = 'R'.
*> \endverbatim
*>
*> \param[in] LDC
*> \verbatim
*> LDC is INTEGER
*> The leading dimension of the array C. LDC >= max(1,M).
*> \endverbatim
*>
*> \param[out] WORK
*> \verbatim
*> WORK is REAL array, dimension
*> (N) if SIDE = 'L'
*> or (M) if SIDE = 'R'
*> \endverbatim
*
* Authors:
* ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \date November 2011
*
*> \ingroup realOTHERauxiliary
*
* =====================================================================
SUBROUTINE SLARF( SIDE, M, N, V, INCV, TAU, C, LDC, WORK )
*
* -- LAPACK auxiliary routine (version 3.4.0) --
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
* November 2011
*
* .. Scalar Arguments ..
CHARACTER SIDE
INTEGER INCV, LDC, M, N
REAL TAU
* ..
* .. Array Arguments ..
REAL C( LDC, * ), V( * ), WORK( * )
* ..
*
* =====================================================================
*
* .. Parameters ..
REAL ONE, ZERO
PARAMETER ( ONE = 1.0E+0, ZERO = 0.0E+0 )
* ..
* .. Local Scalars ..
LOGICAL APPLYLEFT
INTEGER I, LASTV, LASTC
* ..
* .. External Subroutines ..
EXTERNAL SGEMV, SGER
* ..
* .. External Functions ..
LOGICAL LSAME
INTEGER ILASLR, ILASLC
EXTERNAL LSAME, ILASLR, ILASLC
* ..
* .. Executable Statements ..
*
APPLYLEFT = LSAME( SIDE, 'L' )
LASTV = 0
LASTC = 0
IF( TAU.NE.ZERO ) THEN
! Set up variables for scanning V. LASTV begins pointing to the end
! of V.
IF( APPLYLEFT ) THEN
LASTV = M
ELSE
LASTV = N
END IF
IF( INCV.GT.0 ) THEN
I = 1 + (LASTV-1) * INCV
ELSE
I = 1
END IF
! Look for the last non-zero row in V.
DO WHILE( LASTV.GT.0 .AND. V( I ).EQ.ZERO )
LASTV = LASTV - 1
I = I - INCV
END DO
IF( APPLYLEFT ) THEN
! Scan for the last non-zero column in C(1:lastv,:).
LASTC = ILASLC(LASTV, N, C, LDC)
ELSE
! Scan for the last non-zero row in C(:,1:lastv).
LASTC = ILASLR(M, LASTV, C, LDC)
END IF
END IF
! Note that lastc.eq.0 renders the BLAS operations null; no special
! case is needed at this level.
IF( APPLYLEFT ) THEN
*
* Form H * C
*
IF( LASTV.GT.0 ) THEN
*
* w(1:lastc,1) := C(1:lastv,1:lastc)**T * v(1:lastv,1)
*
CALL SGEMV( 'Transpose', LASTV, LASTC, ONE, C, LDC, V, INCV,
$ ZERO, WORK, 1 )
*
* C(1:lastv,1:lastc) := C(...) - v(1:lastv,1) * w(1:lastc,1)**T
*
CALL SGER( LASTV, LASTC, -TAU, V, INCV, WORK, 1, C, LDC )
END IF
ELSE
*
* Form C * H
*
IF( LASTV.GT.0 ) THEN
*
* w(1:lastc,1) := C(1:lastc,1:lastv) * v(1:lastv,1)
*
CALL SGEMV( 'No transpose', LASTC, LASTV, ONE, C, LDC,
$ V, INCV, ZERO, WORK, 1 )
*
* C(1:lastc,1:lastv) := C(...) - w(1:lastc,1) * v(1:lastv,1)**T
*
CALL SGER( LASTC, LASTV, -TAU, WORK, 1, V, INCV, C, LDC )
END IF
END IF
RETURN
*
* End of SLARF
*
END

763
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*> \brief \b SLARFB
*
* =========== DOCUMENTATION ===========
*
* Online html documentation available at
* http://www.netlib.org/lapack/explore-html/
*
*> \htmlonly
*> Download SLARFB + dependencies
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/slarfb.f">
*> [TGZ]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/slarfb.f">
*> [ZIP]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/slarfb.f">
*> [TXT]</a>
*> \endhtmlonly
*
* Definition:
* ===========
*
* SUBROUTINE SLARFB( SIDE, TRANS, DIRECT, STOREV, M, N, K, V, LDV,
* T, LDT, C, LDC, WORK, LDWORK )
*
* .. Scalar Arguments ..
* CHARACTER DIRECT, SIDE, STOREV, TRANS
* INTEGER K, LDC, LDT, LDV, LDWORK, M, N
* ..
* .. Array Arguments ..
* REAL C( LDC, * ), T( LDT, * ), V( LDV, * ),
* $ WORK( LDWORK, * )
* ..
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> SLARFB applies a real block reflector H or its transpose H**T to a
*> real m by n matrix C, from either the left or the right.
*> \endverbatim
*
* Arguments:
* ==========
*
*> \param[in] SIDE
*> \verbatim
*> SIDE is CHARACTER*1
*> = 'L': apply H or H**T from the Left
*> = 'R': apply H or H**T from the Right
*> \endverbatim
*>
*> \param[in] TRANS
*> \verbatim
*> TRANS is CHARACTER*1
*> = 'N': apply H (No transpose)
*> = 'T': apply H**T (Transpose)
*> \endverbatim
*>
*> \param[in] DIRECT
*> \verbatim
*> DIRECT is CHARACTER*1
*> Indicates how H is formed from a product of elementary
*> reflectors
*> = 'F': H = H(1) H(2) . . . H(k) (Forward)
*> = 'B': H = H(k) . . . H(2) H(1) (Backward)
*> \endverbatim
*>
*> \param[in] STOREV
*> \verbatim
*> STOREV is CHARACTER*1
*> Indicates how the vectors which define the elementary
*> reflectors are stored:
*> = 'C': Columnwise
*> = 'R': Rowwise
*> \endverbatim
*>
*> \param[in] M
*> \verbatim
*> M is INTEGER
*> The number of rows of the matrix C.
*> \endverbatim
*>
*> \param[in] N
*> \verbatim
*> N is INTEGER
*> The number of columns of the matrix C.
*> \endverbatim
*>
*> \param[in] K
*> \verbatim
*> K is INTEGER
*> The order of the matrix T (= the number of elementary
*> reflectors whose product defines the block reflector).
*> \endverbatim
*>
*> \param[in] V
*> \verbatim
*> V is REAL array, dimension
*> (LDV,K) if STOREV = 'C'
*> (LDV,M) if STOREV = 'R' and SIDE = 'L'
*> (LDV,N) if STOREV = 'R' and SIDE = 'R'
*> The matrix V. See Further Details.
*> \endverbatim
*>
*> \param[in] LDV
*> \verbatim
*> LDV is INTEGER
*> The leading dimension of the array V.
*> If STOREV = 'C' and SIDE = 'L', LDV >= max(1,M);
*> if STOREV = 'C' and SIDE = 'R', LDV >= max(1,N);
*> if STOREV = 'R', LDV >= K.
*> \endverbatim
*>
*> \param[in] T
*> \verbatim
*> T is REAL array, dimension (LDT,K)
*> The triangular k by k matrix T in the representation of the
*> block reflector.
*> \endverbatim
*>
*> \param[in] LDT
*> \verbatim
*> LDT is INTEGER
*> The leading dimension of the array T. LDT >= K.
*> \endverbatim
*>
*> \param[in,out] C
*> \verbatim
*> C is REAL array, dimension (LDC,N)
*> On entry, the m by n matrix C.
*> On exit, C is overwritten by H*C or H**T*C or C*H or C*H**T.
*> \endverbatim
*>
*> \param[in] LDC
*> \verbatim
*> LDC is INTEGER
*> The leading dimension of the array C. LDC >= max(1,M).
*> \endverbatim
*>
*> \param[out] WORK
*> \verbatim
*> WORK is REAL array, dimension (LDWORK,K)
*> \endverbatim
*>
*> \param[in] LDWORK
*> \verbatim
*> LDWORK is INTEGER
*> The leading dimension of the array WORK.
*> If SIDE = 'L', LDWORK >= max(1,N);
*> if SIDE = 'R', LDWORK >= max(1,M).
*> \endverbatim
*
* Authors:
* ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \date November 2011
*
*> \ingroup realOTHERauxiliary
*
*> \par Further Details:
* =====================
*>
*> \verbatim
*>
*> The shape of the matrix V and the storage of the vectors which define
*> the H(i) is best illustrated by the following example with n = 5 and
*> k = 3. The elements equal to 1 are not stored; the corresponding
*> array elements are modified but restored on exit. The rest of the
*> array is not used.
*>
*> DIRECT = 'F' and STOREV = 'C': DIRECT = 'F' and STOREV = 'R':
*>
*> V = ( 1 ) V = ( 1 v1 v1 v1 v1 )
*> ( v1 1 ) ( 1 v2 v2 v2 )
*> ( v1 v2 1 ) ( 1 v3 v3 )
*> ( v1 v2 v3 )
*> ( v1 v2 v3 )
*>
*> DIRECT = 'B' and STOREV = 'C': DIRECT = 'B' and STOREV = 'R':
*>
*> V = ( v1 v2 v3 ) V = ( v1 v1 1 )
*> ( v1 v2 v3 ) ( v2 v2 v2 1 )
*> ( 1 v2 v3 ) ( v3 v3 v3 v3 1 )
*> ( 1 v3 )
*> ( 1 )
*> \endverbatim
*>
* =====================================================================
SUBROUTINE SLARFB( SIDE, TRANS, DIRECT, STOREV, M, N, K, V, LDV,
$ T, LDT, C, LDC, WORK, LDWORK )
*
* -- LAPACK auxiliary routine (version 3.4.0) --
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
* November 2011
*
* .. Scalar Arguments ..
CHARACTER DIRECT, SIDE, STOREV, TRANS
INTEGER K, LDC, LDT, LDV, LDWORK, M, N
* ..
* .. Array Arguments ..
REAL C( LDC, * ), T( LDT, * ), V( LDV, * ),
$ WORK( LDWORK, * )
* ..
*
* =====================================================================
*
* .. Parameters ..
REAL ONE
PARAMETER ( ONE = 1.0E+0 )
* ..
* .. Local Scalars ..
CHARACTER TRANST
INTEGER I, J, LASTV, LASTC
* ..
* .. External Functions ..
LOGICAL LSAME
INTEGER ILASLR, ILASLC
EXTERNAL LSAME, ILASLR, ILASLC
* ..
* .. External Subroutines ..
EXTERNAL SCOPY, SGEMM, STRMM
* ..
* .. Executable Statements ..
*
* Quick return if possible
*
IF( M.LE.0 .OR. N.LE.0 )
$ RETURN
*
IF( LSAME( TRANS, 'N' ) ) THEN
TRANST = 'T'
ELSE
TRANST = 'N'
END IF
*
IF( LSAME( STOREV, 'C' ) ) THEN
*
IF( LSAME( DIRECT, 'F' ) ) THEN
*
* Let V = ( V1 ) (first K rows)
* ( V2 )
* where V1 is unit lower triangular.
*
IF( LSAME( SIDE, 'L' ) ) THEN
*
* Form H * C or H**T * C where C = ( C1 )
* ( C2 )
*
LASTV = MAX( K, ILASLR( M, K, V, LDV ) )
LASTC = ILASLC( LASTV, N, C, LDC )
*
* W := C**T * V = (C1**T * V1 + C2**T * V2) (stored in WORK)
*
* W := C1**T
*
DO 10 J = 1, K
CALL SCOPY( LASTC, C( J, 1 ), LDC, WORK( 1, J ), 1 )
10 CONTINUE
*
* W := W * V1
*
CALL STRMM( 'Right', 'Lower', 'No transpose', 'Unit',
$ LASTC, K, ONE, V, LDV, WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C2**T *V2
*
CALL SGEMM( 'Transpose', 'No transpose',
$ LASTC, K, LASTV-K,
$ ONE, C( K+1, 1 ), LDC, V( K+1, 1 ), LDV,
$ ONE, WORK, LDWORK )
END IF
*
* W := W * T**T or W * T
*
CALL STRMM( 'Right', 'Upper', TRANST, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - V * W**T
*
IF( LASTV.GT.K ) THEN
*
* C2 := C2 - V2 * W**T
*
CALL SGEMM( 'No transpose', 'Transpose',
$ LASTV-K, LASTC, K,
$ -ONE, V( K+1, 1 ), LDV, WORK, LDWORK, ONE,
$ C( K+1, 1 ), LDC )
END IF
*
* W := W * V1**T
*
CALL STRMM( 'Right', 'Lower', 'Transpose', 'Unit',
$ LASTC, K, ONE, V, LDV, WORK, LDWORK )
*
* C1 := C1 - W**T
*
DO 30 J = 1, K
DO 20 I = 1, LASTC
C( J, I ) = C( J, I ) - WORK( I, J )
20 CONTINUE
30 CONTINUE
*
ELSE IF( LSAME( SIDE, 'R' ) ) THEN
*
* Form C * H or C * H**T where C = ( C1 C2 )
*
LASTV = MAX( K, ILASLR( N, K, V, LDV ) )
LASTC = ILASLR( M, LASTV, C, LDC )
*
* W := C * V = (C1*V1 + C2*V2) (stored in WORK)
*
* W := C1
*
DO 40 J = 1, K
CALL SCOPY( LASTC, C( 1, J ), 1, WORK( 1, J ), 1 )
40 CONTINUE
*
* W := W * V1
*
CALL STRMM( 'Right', 'Lower', 'No transpose', 'Unit',
$ LASTC, K, ONE, V, LDV, WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C2 * V2
*
CALL SGEMM( 'No transpose', 'No transpose',
$ LASTC, K, LASTV-K,
$ ONE, C( 1, K+1 ), LDC, V( K+1, 1 ), LDV,
$ ONE, WORK, LDWORK )
END IF
*
* W := W * T or W * T**T
*
CALL STRMM( 'Right', 'Upper', TRANS, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - W * V**T
*
IF( LASTV.GT.K ) THEN
*
* C2 := C2 - W * V2**T
*
CALL SGEMM( 'No transpose', 'Transpose',
$ LASTC, LASTV-K, K,
$ -ONE, WORK, LDWORK, V( K+1, 1 ), LDV, ONE,
$ C( 1, K+1 ), LDC )
END IF
*
* W := W * V1**T
*
CALL STRMM( 'Right', 'Lower', 'Transpose', 'Unit',
$ LASTC, K, ONE, V, LDV, WORK, LDWORK )
*
* C1 := C1 - W
*
DO 60 J = 1, K
DO 50 I = 1, LASTC
C( I, J ) = C( I, J ) - WORK( I, J )
50 CONTINUE
60 CONTINUE
END IF
*
ELSE
*
* Let V = ( V1 )
* ( V2 ) (last K rows)
* where V2 is unit upper triangular.
*
IF( LSAME( SIDE, 'L' ) ) THEN
*
* Form H * C or H**T * C where C = ( C1 )
* ( C2 )
*
LASTV = MAX( K, ILASLR( M, K, V, LDV ) )
LASTC = ILASLC( LASTV, N, C, LDC )
*
* W := C**T * V = (C1**T * V1 + C2**T * V2) (stored in WORK)
*
* W := C2**T
*
DO 70 J = 1, K
CALL SCOPY( LASTC, C( LASTV-K+J, 1 ), LDC,
$ WORK( 1, J ), 1 )
70 CONTINUE
*
* W := W * V2
*
CALL STRMM( 'Right', 'Upper', 'No transpose', 'Unit',
$ LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
$ WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C1**T*V1
*
CALL SGEMM( 'Transpose', 'No transpose',
$ LASTC, K, LASTV-K, ONE, C, LDC, V, LDV,
$ ONE, WORK, LDWORK )
END IF
*
* W := W * T**T or W * T
*
CALL STRMM( 'Right', 'Lower', TRANST, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - V * W**T
*
IF( LASTV.GT.K ) THEN
*
* C1 := C1 - V1 * W**T
*
CALL SGEMM( 'No transpose', 'Transpose',
$ LASTV-K, LASTC, K, -ONE, V, LDV, WORK, LDWORK,
$ ONE, C, LDC )
END IF
*
* W := W * V2**T
*
CALL STRMM( 'Right', 'Upper', 'Transpose', 'Unit',
$ LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
$ WORK, LDWORK )
*
* C2 := C2 - W**T
*
DO 90 J = 1, K
DO 80 I = 1, LASTC
C( LASTV-K+J, I ) = C( LASTV-K+J, I ) - WORK(I, J)
80 CONTINUE
90 CONTINUE
*
ELSE IF( LSAME( SIDE, 'R' ) ) THEN
*
* Form C * H or C * H**T where C = ( C1 C2 )
*
LASTV = MAX( K, ILASLR( N, K, V, LDV ) )
LASTC = ILASLR( M, LASTV, C, LDC )
*
* W := C * V = (C1*V1 + C2*V2) (stored in WORK)
*
* W := C2
*
DO 100 J = 1, K
CALL SCOPY( LASTC, C( 1, N-K+J ), 1, WORK( 1, J ), 1 )
100 CONTINUE
*
* W := W * V2
*
CALL STRMM( 'Right', 'Upper', 'No transpose', 'Unit',
$ LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
$ WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C1 * V1
*
CALL SGEMM( 'No transpose', 'No transpose',
$ LASTC, K, LASTV-K, ONE, C, LDC, V, LDV,
$ ONE, WORK, LDWORK )
END IF
*
* W := W * T or W * T**T
*
CALL STRMM( 'Right', 'Lower', TRANS, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - W * V**T
*
IF( LASTV.GT.K ) THEN
*
* C1 := C1 - W * V1**T
*
CALL SGEMM( 'No transpose', 'Transpose',
$ LASTC, LASTV-K, K, -ONE, WORK, LDWORK, V, LDV,
$ ONE, C, LDC )
END IF
*
* W := W * V2**T
*
CALL STRMM( 'Right', 'Upper', 'Transpose', 'Unit',
$ LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
$ WORK, LDWORK )
*
* C2 := C2 - W
*
DO 120 J = 1, K
DO 110 I = 1, LASTC
C( I, LASTV-K+J ) = C( I, LASTV-K+J ) - WORK(I, J)
110 CONTINUE
120 CONTINUE
END IF
END IF
*
ELSE IF( LSAME( STOREV, 'R' ) ) THEN
*
IF( LSAME( DIRECT, 'F' ) ) THEN
*
* Let V = ( V1 V2 ) (V1: first K columns)
* where V1 is unit upper triangular.
*
IF( LSAME( SIDE, 'L' ) ) THEN
*
* Form H * C or H**T * C where C = ( C1 )
* ( C2 )
*
LASTV = MAX( K, ILASLC( K, M, V, LDV ) )
LASTC = ILASLC( LASTV, N, C, LDC )
*
* W := C**T * V**T = (C1**T * V1**T + C2**T * V2**T) (stored in WORK)
*
* W := C1**T
*
DO 130 J = 1, K
CALL SCOPY( LASTC, C( J, 1 ), LDC, WORK( 1, J ), 1 )
130 CONTINUE
*
* W := W * V1**T
*
CALL STRMM( 'Right', 'Upper', 'Transpose', 'Unit',
$ LASTC, K, ONE, V, LDV, WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C2**T*V2**T
*
CALL SGEMM( 'Transpose', 'Transpose',
$ LASTC, K, LASTV-K,
$ ONE, C( K+1, 1 ), LDC, V( 1, K+1 ), LDV,
$ ONE, WORK, LDWORK )
END IF
*
* W := W * T**T or W * T
*
CALL STRMM( 'Right', 'Upper', TRANST, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - V**T * W**T
*
IF( LASTV.GT.K ) THEN
*
* C2 := C2 - V2**T * W**T
*
CALL SGEMM( 'Transpose', 'Transpose',
$ LASTV-K, LASTC, K,
$ -ONE, V( 1, K+1 ), LDV, WORK, LDWORK,
$ ONE, C( K+1, 1 ), LDC )
END IF
*
* W := W * V1
*
CALL STRMM( 'Right', 'Upper', 'No transpose', 'Unit',
$ LASTC, K, ONE, V, LDV, WORK, LDWORK )
*
* C1 := C1 - W**T
*
DO 150 J = 1, K
DO 140 I = 1, LASTC
C( J, I ) = C( J, I ) - WORK( I, J )
140 CONTINUE
150 CONTINUE
*
ELSE IF( LSAME( SIDE, 'R' ) ) THEN
*
* Form C * H or C * H**T where C = ( C1 C2 )
*
LASTV = MAX( K, ILASLC( K, N, V, LDV ) )
LASTC = ILASLR( M, LASTV, C, LDC )
*
* W := C * V**T = (C1*V1**T + C2*V2**T) (stored in WORK)
*
* W := C1
*
DO 160 J = 1, K
CALL SCOPY( LASTC, C( 1, J ), 1, WORK( 1, J ), 1 )
160 CONTINUE
*
* W := W * V1**T
*
CALL STRMM( 'Right', 'Upper', 'Transpose', 'Unit',
$ LASTC, K, ONE, V, LDV, WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C2 * V2**T
*
CALL SGEMM( 'No transpose', 'Transpose',
$ LASTC, K, LASTV-K,
$ ONE, C( 1, K+1 ), LDC, V( 1, K+1 ), LDV,
$ ONE, WORK, LDWORK )
END IF
*
* W := W * T or W * T**T
*
CALL STRMM( 'Right', 'Upper', TRANS, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - W * V
*
IF( LASTV.GT.K ) THEN
*
* C2 := C2 - W * V2
*
CALL SGEMM( 'No transpose', 'No transpose',
$ LASTC, LASTV-K, K,
$ -ONE, WORK, LDWORK, V( 1, K+1 ), LDV,
$ ONE, C( 1, K+1 ), LDC )
END IF
*
* W := W * V1
*
CALL STRMM( 'Right', 'Upper', 'No transpose', 'Unit',
$ LASTC, K, ONE, V, LDV, WORK, LDWORK )
*
* C1 := C1 - W
*
DO 180 J = 1, K
DO 170 I = 1, LASTC
C( I, J ) = C( I, J ) - WORK( I, J )
170 CONTINUE
180 CONTINUE
*
END IF
*
ELSE
*
* Let V = ( V1 V2 ) (V2: last K columns)
* where V2 is unit lower triangular.
*
IF( LSAME( SIDE, 'L' ) ) THEN
*
* Form H * C or H**T * C where C = ( C1 )
* ( C2 )
*
LASTV = MAX( K, ILASLC( K, M, V, LDV ) )
LASTC = ILASLC( LASTV, N, C, LDC )
*
* W := C**T * V**T = (C1**T * V1**T + C2**T * V2**T) (stored in WORK)
*
* W := C2**T
*
DO 190 J = 1, K
CALL SCOPY( LASTC, C( LASTV-K+J, 1 ), LDC,
$ WORK( 1, J ), 1 )
190 CONTINUE
*
* W := W * V2**T
*
CALL STRMM( 'Right', 'Lower', 'Transpose', 'Unit',
$ LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV,
$ WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C1**T * V1**T
*
CALL SGEMM( 'Transpose', 'Transpose',
$ LASTC, K, LASTV-K, ONE, C, LDC, V, LDV,
$ ONE, WORK, LDWORK )
END IF
*
* W := W * T**T or W * T
*
CALL STRMM( 'Right', 'Lower', TRANST, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - V**T * W**T
*
IF( LASTV.GT.K ) THEN
*
* C1 := C1 - V1**T * W**T
*
CALL SGEMM( 'Transpose', 'Transpose',
$ LASTV-K, LASTC, K, -ONE, V, LDV, WORK, LDWORK,
$ ONE, C, LDC )
END IF
*
* W := W * V2
*
CALL STRMM( 'Right', 'Lower', 'No transpose', 'Unit',
$ LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV,
$ WORK, LDWORK )
*
* C2 := C2 - W**T
*
DO 210 J = 1, K
DO 200 I = 1, LASTC
C( LASTV-K+J, I ) = C( LASTV-K+J, I ) - WORK(I, J)
200 CONTINUE
210 CONTINUE
*
ELSE IF( LSAME( SIDE, 'R' ) ) THEN
*
* Form C * H or C * H**T where C = ( C1 C2 )
*
LASTV = MAX( K, ILASLC( K, N, V, LDV ) )
LASTC = ILASLR( M, LASTV, C, LDC )
*
* W := C * V**T = (C1*V1**T + C2*V2**T) (stored in WORK)
*
* W := C2
*
DO 220 J = 1, K
CALL SCOPY( LASTC, C( 1, LASTV-K+J ), 1,
$ WORK( 1, J ), 1 )
220 CONTINUE
*
* W := W * V2**T
*
CALL STRMM( 'Right', 'Lower', 'Transpose', 'Unit',
$ LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV,
$ WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C1 * V1**T
*
CALL SGEMM( 'No transpose', 'Transpose',
$ LASTC, K, LASTV-K, ONE, C, LDC, V, LDV,
$ ONE, WORK, LDWORK )
END IF
*
* W := W * T or W * T**T
*
CALL STRMM( 'Right', 'Lower', TRANS, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - W * V
*
IF( LASTV.GT.K ) THEN
*
* C1 := C1 - W * V1
*
CALL SGEMM( 'No transpose', 'No transpose',
$ LASTC, LASTV-K, K, -ONE, WORK, LDWORK, V, LDV,
$ ONE, C, LDC )
END IF
*
* W := W * V2
*
CALL STRMM( 'Right', 'Lower', 'No transpose', 'Unit',
$ LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV,
$ WORK, LDWORK )
*
* C1 := C1 - W
*
DO 240 J = 1, K
DO 230 I = 1, LASTC
C( I, LASTV-K+J ) = C( I, LASTV-K+J )
$ - WORK( I, J )
230 CONTINUE
240 CONTINUE
*
END IF
*
END IF
END IF
*
RETURN
*
* End of SLARFB
*
END

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*> \brief \b SLARFG
*
* =========== DOCUMENTATION ===========
*
* Online html documentation available at
* http://www.netlib.org/lapack/explore-html/
*
*> \htmlonly
*> Download SLARFG + dependencies
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/slarfg.f">
*> [TGZ]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/slarfg.f">
*> [ZIP]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/slarfg.f">
*> [TXT]</a>
*> \endhtmlonly
*
* Definition:
* ===========
*
* SUBROUTINE SLARFG( N, ALPHA, X, INCX, TAU )
*
* .. Scalar Arguments ..
* INTEGER INCX, N
* REAL ALPHA, TAU
* ..
* .. Array Arguments ..
* REAL X( * )
* ..
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> SLARFG generates a real elementary reflector H of order n, such
*> that
*>
*> H * ( alpha ) = ( beta ), H**T * H = I.
*> ( x ) ( 0 )
*>
*> where alpha and beta are scalars, and x is an (n-1)-element real
*> vector. H is represented in the form
*>
*> H = I - tau * ( 1 ) * ( 1 v**T ) ,
*> ( v )
*>
*> where tau is a real scalar and v is a real (n-1)-element
*> vector.
*>
*> If the elements of x are all zero, then tau = 0 and H is taken to be
*> the unit matrix.
*>
*> Otherwise 1 <= tau <= 2.
*> \endverbatim
*
* Arguments:
* ==========
*
*> \param[in] N
*> \verbatim
*> N is INTEGER
*> The order of the elementary reflector.
*> \endverbatim
*>
*> \param[in,out] ALPHA
*> \verbatim
*> ALPHA is REAL
*> On entry, the value alpha.
*> On exit, it is overwritten with the value beta.
*> \endverbatim
*>
*> \param[in,out] X
*> \verbatim
*> X is REAL array, dimension
*> (1+(N-2)*abs(INCX))
*> On entry, the vector x.
*> On exit, it is overwritten with the vector v.
*> \endverbatim
*>
*> \param[in] INCX
*> \verbatim
*> INCX is INTEGER
*> The increment between elements of X. INCX > 0.
*> \endverbatim
*>
*> \param[out] TAU
*> \verbatim
*> TAU is REAL
*> The value tau.
*> \endverbatim
*
* Authors:
* ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \date November 2011
*
*> \ingroup realOTHERauxiliary
*
* =====================================================================
SUBROUTINE SLARFG( N, ALPHA, X, INCX, TAU )
*
* -- LAPACK auxiliary routine (version 3.4.0) --
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
* November 2011
*
* .. Scalar Arguments ..
INTEGER INCX, N
REAL ALPHA, TAU
* ..
* .. Array Arguments ..
REAL X( * )
* ..
*
* =====================================================================
*
* .. Parameters ..
REAL ONE, ZERO
PARAMETER ( ONE = 1.0E+0, ZERO = 0.0E+0 )
* ..
* .. Local Scalars ..
INTEGER J, KNT
REAL BETA, RSAFMN, SAFMIN, XNORM
* ..
* .. External Functions ..
REAL SLAMCH, SLAPY2, SNRM2
EXTERNAL SLAMCH, SLAPY2, SNRM2
* ..
* .. Intrinsic Functions ..
INTRINSIC ABS, SIGN
* ..
* .. External Subroutines ..
EXTERNAL SSCAL
* ..
* .. Executable Statements ..
*
IF( N.LE.1 ) THEN
TAU = ZERO
RETURN
END IF
*
XNORM = SNRM2( N-1, X, INCX )
*
IF( XNORM.EQ.ZERO ) THEN
*
* H = I
*
TAU = ZERO
ELSE
*
* general case
*
BETA = -SIGN( SLAPY2( ALPHA, XNORM ), ALPHA )
SAFMIN = SLAMCH( 'S' ) / SLAMCH( 'E' )
KNT = 0
IF( ABS( BETA ).LT.SAFMIN ) THEN
*
* XNORM, BETA may be inaccurate; scale X and recompute them
*
RSAFMN = ONE / SAFMIN
10 CONTINUE
KNT = KNT + 1
CALL SSCAL( N-1, RSAFMN, X, INCX )
BETA = BETA*RSAFMN
ALPHA = ALPHA*RSAFMN
IF( ABS( BETA ).LT.SAFMIN )
$ GO TO 10
*
* New BETA is at most 1, at least SAFMIN
*
XNORM = SNRM2( N-1, X, INCX )
BETA = -SIGN( SLAPY2( ALPHA, XNORM ), ALPHA )
END IF
TAU = ( BETA-ALPHA ) / BETA
CALL SSCAL( N-1, ONE / ( ALPHA-BETA ), X, INCX )
*
* If ALPHA is subnormal, it may lose relative accuracy
*
DO 20 J = 1, KNT
BETA = BETA*SAFMIN
20 CONTINUE
ALPHA = BETA
END IF
*
RETURN
*
* End of SLARFG
*
END

326
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*> \brief \b SLARFT
*
* =========== DOCUMENTATION ===========
*
* Online html documentation available at
* http://www.netlib.org/lapack/explore-html/
*
*> \htmlonly
*> Download SLARFT + dependencies
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/slarft.f">
*> [TGZ]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/slarft.f">
*> [ZIP]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/slarft.f">
*> [TXT]</a>
*> \endhtmlonly
*
* Definition:
* ===========
*
* SUBROUTINE SLARFT( DIRECT, STOREV, N, K, V, LDV, TAU, T, LDT )
*
* .. Scalar Arguments ..
* CHARACTER DIRECT, STOREV
* INTEGER K, LDT, LDV, N
* ..
* .. Array Arguments ..
* REAL T( LDT, * ), TAU( * ), V( LDV, * )
* ..
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> SLARFT forms the triangular factor T of a real block reflector H
*> of order n, which is defined as a product of k elementary reflectors.
*>
*> If DIRECT = 'F', H = H(1) H(2) . . . H(k) and T is upper triangular;
*>
*> If DIRECT = 'B', H = H(k) . . . H(2) H(1) and T is lower triangular.
*>
*> If STOREV = 'C', the vector which defines the elementary reflector
*> H(i) is stored in the i-th column of the array V, and
*>
*> H = I - V * T * V**T
*>
*> If STOREV = 'R', the vector which defines the elementary reflector
*> H(i) is stored in the i-th row of the array V, and
*>
*> H = I - V**T * T * V
*> \endverbatim
*
* Arguments:
* ==========
*
*> \param[in] DIRECT
*> \verbatim
*> DIRECT is CHARACTER*1
*> Specifies the order in which the elementary reflectors are
*> multiplied to form the block reflector:
*> = 'F': H = H(1) H(2) . . . H(k) (Forward)
*> = 'B': H = H(k) . . . H(2) H(1) (Backward)
*> \endverbatim
*>
*> \param[in] STOREV
*> \verbatim
*> STOREV is CHARACTER*1
*> Specifies how the vectors which define the elementary
*> reflectors are stored (see also Further Details):
*> = 'C': columnwise
*> = 'R': rowwise
*> \endverbatim
*>
*> \param[in] N
*> \verbatim
*> N is INTEGER
*> The order of the block reflector H. N >= 0.
*> \endverbatim
*>
*> \param[in] K
*> \verbatim
*> K is INTEGER
*> The order of the triangular factor T (= the number of
*> elementary reflectors). K >= 1.
*> \endverbatim
*>
*> \param[in] V
*> \verbatim
*> V is REAL array, dimension
*> (LDV,K) if STOREV = 'C'
*> (LDV,N) if STOREV = 'R'
*> The matrix V. See further details.
*> \endverbatim
*>
*> \param[in] LDV
*> \verbatim
*> LDV is INTEGER
*> The leading dimension of the array V.
*> If STOREV = 'C', LDV >= max(1,N); if STOREV = 'R', LDV >= K.
*> \endverbatim
*>
*> \param[in] TAU
*> \verbatim
*> TAU is REAL array, dimension (K)
*> TAU(i) must contain the scalar factor of the elementary
*> reflector H(i).
*> \endverbatim
*>
*> \param[out] T
*> \verbatim
*> T is REAL array, dimension (LDT,K)
*> The k by k triangular factor T of the block reflector.
*> If DIRECT = 'F', T is upper triangular; if DIRECT = 'B', T is
*> lower triangular. The rest of the array is not used.
*> \endverbatim
*>
*> \param[in] LDT
*> \verbatim
*> LDT is INTEGER
*> The leading dimension of the array T. LDT >= K.
*> \endverbatim
*
* Authors:
* ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \date April 2012
*
*> \ingroup realOTHERauxiliary
*
*> \par Further Details:
* =====================
*>
*> \verbatim
*>
*> The shape of the matrix V and the storage of the vectors which define
*> the H(i) is best illustrated by the following example with n = 5 and
*> k = 3. The elements equal to 1 are not stored.
*>
*> DIRECT = 'F' and STOREV = 'C': DIRECT = 'F' and STOREV = 'R':
*>
*> V = ( 1 ) V = ( 1 v1 v1 v1 v1 )
*> ( v1 1 ) ( 1 v2 v2 v2 )
*> ( v1 v2 1 ) ( 1 v3 v3 )
*> ( v1 v2 v3 )
*> ( v1 v2 v3 )
*>
*> DIRECT = 'B' and STOREV = 'C': DIRECT = 'B' and STOREV = 'R':
*>
*> V = ( v1 v2 v3 ) V = ( v1 v1 1 )
*> ( v1 v2 v3 ) ( v2 v2 v2 1 )
*> ( 1 v2 v3 ) ( v3 v3 v3 v3 1 )
*> ( 1 v3 )
*> ( 1 )
*> \endverbatim
*>
* =====================================================================
SUBROUTINE SLARFT( DIRECT, STOREV, N, K, V, LDV, TAU, T, LDT )
*
* -- LAPACK auxiliary routine (version 3.4.1) --
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
* April 2012
*
* .. Scalar Arguments ..
CHARACTER DIRECT, STOREV
INTEGER K, LDT, LDV, N
* ..
* .. Array Arguments ..
REAL T( LDT, * ), TAU( * ), V( LDV, * )
* ..
*
* =====================================================================
*
* .. Parameters ..
REAL ONE, ZERO
PARAMETER ( ONE = 1.0E+0, ZERO = 0.0E+0 )
* ..
* .. Local Scalars ..
INTEGER I, J, PREVLASTV, LASTV
* ..
* .. External Subroutines ..
EXTERNAL SGEMV, STRMV
* ..
* .. External Functions ..
LOGICAL LSAME
EXTERNAL LSAME
* ..
* .. Executable Statements ..
*
* Quick return if possible
*
IF( N.EQ.0 )
$ RETURN
*
IF( LSAME( DIRECT, 'F' ) ) THEN
PREVLASTV = N
DO I = 1, K
PREVLASTV = MAX( I, PREVLASTV )
IF( TAU( I ).EQ.ZERO ) THEN
*
* H(i) = I
*
DO J = 1, I
T( J, I ) = ZERO
END DO
ELSE
*
* general case
*
IF( LSAME( STOREV, 'C' ) ) THEN
* Skip any trailing zeros.
DO LASTV = N, I+1, -1
IF( V( LASTV, I ).NE.ZERO ) EXIT
END DO
DO J = 1, I-1
T( J, I ) = -TAU( I ) * V( I , J )
END DO
J = MIN( LASTV, PREVLASTV )
*
* T(1:i-1,i) := - tau(i) * V(i:j,1:i-1)**T * V(i:j,i)
*
CALL SGEMV( 'Transpose', J-I, I-1, -TAU( I ),
$ V( I+1, 1 ), LDV, V( I+1, I ), 1, ONE,
$ T( 1, I ), 1 )
ELSE
* Skip any trailing zeros.
DO LASTV = N, I+1, -1
IF( V( I, LASTV ).NE.ZERO ) EXIT
END DO
DO J = 1, I-1
T( J, I ) = -TAU( I ) * V( J , I )
END DO
J = MIN( LASTV, PREVLASTV )
*
* T(1:i-1,i) := - tau(i) * V(1:i-1,i:j) * V(i,i:j)**T
*
CALL SGEMV( 'No transpose', I-1, J-I, -TAU( I ),
$ V( 1, I+1 ), LDV, V( I, I+1 ), LDV,
$ ONE, T( 1, I ), 1 )
END IF
*
* T(1:i-1,i) := T(1:i-1,1:i-1) * T(1:i-1,i)
*
CALL STRMV( 'Upper', 'No transpose', 'Non-unit', I-1, T,
$ LDT, T( 1, I ), 1 )
T( I, I ) = TAU( I )
IF( I.GT.1 ) THEN
PREVLASTV = MAX( PREVLASTV, LASTV )
ELSE
PREVLASTV = LASTV
END IF
END IF
END DO
ELSE
PREVLASTV = 1
DO I = K, 1, -1
IF( TAU( I ).EQ.ZERO ) THEN
*
* H(i) = I
*
DO J = I, K
T( J, I ) = ZERO
END DO
ELSE
*
* general case
*
IF( I.LT.K ) THEN
IF( LSAME( STOREV, 'C' ) ) THEN
* Skip any leading zeros.
DO LASTV = 1, I-1
IF( V( LASTV, I ).NE.ZERO ) EXIT
END DO
DO J = I+1, K
T( J, I ) = -TAU( I ) * V( N-K+I , J )
END DO
J = MAX( LASTV, PREVLASTV )
*
* T(i+1:k,i) = -tau(i) * V(j:n-k+i,i+1:k)**T * V(j:n-k+i,i)
*
CALL SGEMV( 'Transpose', N-K+I-J, K-I, -TAU( I ),
$ V( J, I+1 ), LDV, V( J, I ), 1, ONE,
$ T( I+1, I ), 1 )
ELSE
* Skip any leading zeros.
DO LASTV = 1, I-1
IF( V( I, LASTV ).NE.ZERO ) EXIT
END DO
DO J = I+1, K
T( J, I ) = -TAU( I ) * V( J, N-K+I )
END DO
J = MAX( LASTV, PREVLASTV )
*
* T(i+1:k,i) = -tau(i) * V(i+1:k,j:n-k+i) * V(i,j:n-k+i)**T
*
CALL SGEMV( 'No transpose', K-I, N-K+I-J,
$ -TAU( I ), V( I+1, J ), LDV, V( I, J ), LDV,
$ ONE, T( I+1, I ), 1 )
END IF
*
* T(i+1:k,i) := T(i+1:k,i+1:k) * T(i+1:k,i)
*
CALL STRMV( 'Lower', 'No transpose', 'Non-unit', K-I,
$ T( I+1, I+1 ), LDT, T( I+1, I ), 1 )
IF( I.GT.1 ) THEN
PREVLASTV = MIN( PREVLASTV, LASTV )
ELSE
PREVLASTV = LASTV
END IF
END IF
T( I, I ) = TAU( I )
END IF
END DO
END IF
RETURN
*
* End of SLARFT
*
END

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*> \brief \b ZLARF
*
* =========== DOCUMENTATION ===========
*
* Online html documentation available at
* http://www.netlib.org/lapack/explore-html/
*
*> \htmlonly
*> Download ZLARF + dependencies
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/zlarf.f">
*> [TGZ]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/zlarf.f">
*> [ZIP]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/zlarf.f">
*> [TXT]</a>
*> \endhtmlonly
*
* Definition:
* ===========
*
* SUBROUTINE ZLARF( SIDE, M, N, V, INCV, TAU, C, LDC, WORK )
*
* .. Scalar Arguments ..
* CHARACTER SIDE
* INTEGER INCV, LDC, M, N
* COMPLEX*16 TAU
* ..
* .. Array Arguments ..
* COMPLEX*16 C( LDC, * ), V( * ), WORK( * )
* ..
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> ZLARF applies a complex elementary reflector H to a complex M-by-N
*> matrix C, from either the left or the right. H is represented in the
*> form
*>
*> H = I - tau * v * v**H
*>
*> where tau is a complex scalar and v is a complex vector.
*>
*> If tau = 0, then H is taken to be the unit matrix.
*>
*> To apply H**H, supply conjg(tau) instead
*> tau.
*> \endverbatim
*
* Arguments:
* ==========
*
*> \param[in] SIDE
*> \verbatim
*> SIDE is CHARACTER*1
*> = 'L': form H * C
*> = 'R': form C * H
*> \endverbatim
*>
*> \param[in] M
*> \verbatim
*> M is INTEGER
*> The number of rows of the matrix C.
*> \endverbatim
*>
*> \param[in] N
*> \verbatim
*> N is INTEGER
*> The number of columns of the matrix C.
*> \endverbatim
*>
*> \param[in] V
*> \verbatim
*> V is COMPLEX*16 array, dimension
*> (1 + (M-1)*abs(INCV)) if SIDE = 'L'
*> or (1 + (N-1)*abs(INCV)) if SIDE = 'R'
*> The vector v in the representation of H. V is not used if
*> TAU = 0.
*> \endverbatim
*>
*> \param[in] INCV
*> \verbatim
*> INCV is INTEGER
*> The increment between elements of v. INCV <> 0.
*> \endverbatim
*>
*> \param[in] TAU
*> \verbatim
*> TAU is COMPLEX*16
*> The value tau in the representation of H.
*> \endverbatim
*>
*> \param[in,out] C
*> \verbatim
*> C is COMPLEX*16 array, dimension (LDC,N)
*> On entry, the M-by-N matrix C.
*> On exit, C is overwritten by the matrix H * C if SIDE = 'L',
*> or C * H if SIDE = 'R'.
*> \endverbatim
*>
*> \param[in] LDC
*> \verbatim
*> LDC is INTEGER
*> The leading dimension of the array C. LDC >= max(1,M).
*> \endverbatim
*>
*> \param[out] WORK
*> \verbatim
*> WORK is COMPLEX*16 array, dimension
*> (N) if SIDE = 'L'
*> or (M) if SIDE = 'R'
*> \endverbatim
*
* Authors:
* ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \date November 2011
*
*> \ingroup complex16OTHERauxiliary
*
* =====================================================================
SUBROUTINE ZLARF( SIDE, M, N, V, INCV, TAU, C, LDC, WORK )
*
* -- LAPACK auxiliary routine (version 3.4.0) --
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
* November 2011
*
* .. Scalar Arguments ..
CHARACTER SIDE
INTEGER INCV, LDC, M, N
COMPLEX*16 TAU
* ..
* .. Array Arguments ..
COMPLEX*16 C( LDC, * ), V( * ), WORK( * )
* ..
*
* =====================================================================
*
* .. Parameters ..
COMPLEX*16 ONE, ZERO
PARAMETER ( ONE = ( 1.0D+0, 0.0D+0 ),
$ ZERO = ( 0.0D+0, 0.0D+0 ) )
* ..
* .. Local Scalars ..
LOGICAL APPLYLEFT
INTEGER I, LASTV, LASTC
* ..
* .. External Subroutines ..
EXTERNAL ZGEMV, ZGERC
* ..
* .. External Functions ..
LOGICAL LSAME
INTEGER ILAZLR, ILAZLC
EXTERNAL LSAME, ILAZLR, ILAZLC
* ..
* .. Executable Statements ..
*
APPLYLEFT = LSAME( SIDE, 'L' )
LASTV = 0
LASTC = 0
IF( TAU.NE.ZERO ) THEN
* Set up variables for scanning V. LASTV begins pointing to the end
* of V.
IF( APPLYLEFT ) THEN
LASTV = M
ELSE
LASTV = N
END IF
IF( INCV.GT.0 ) THEN
I = 1 + (LASTV-1) * INCV
ELSE
I = 1
END IF
* Look for the last non-zero row in V.
DO WHILE( LASTV.GT.0 .AND. V( I ).EQ.ZERO )
LASTV = LASTV - 1
I = I - INCV
END DO
IF( APPLYLEFT ) THEN
* Scan for the last non-zero column in C(1:lastv,:).
LASTC = ILAZLC(LASTV, N, C, LDC)
ELSE
* Scan for the last non-zero row in C(:,1:lastv).
LASTC = ILAZLR(M, LASTV, C, LDC)
END IF
END IF
* Note that lastc.eq.0 renders the BLAS operations null; no special
* case is needed at this level.
IF( APPLYLEFT ) THEN
*
* Form H * C
*
IF( LASTV.GT.0 ) THEN
*
* w(1:lastc,1) := C(1:lastv,1:lastc)**H * v(1:lastv,1)
*
CALL ZGEMV( 'Conjugate transpose', LASTV, LASTC, ONE,
$ C, LDC, V, INCV, ZERO, WORK, 1 )
*
* C(1:lastv,1:lastc) := C(...) - v(1:lastv,1) * w(1:lastc,1)**H
*
CALL ZGERC( LASTV, LASTC, -TAU, V, INCV, WORK, 1, C, LDC )
END IF
ELSE
*
* Form C * H
*
IF( LASTV.GT.0 ) THEN
*
* w(1:lastc,1) := C(1:lastc,1:lastv) * v(1:lastv,1)
*
CALL ZGEMV( 'No transpose', LASTC, LASTV, ONE, C, LDC,
$ V, INCV, ZERO, WORK, 1 )
*
* C(1:lastc,1:lastv) := C(...) - w(1:lastc,1) * v(1:lastv,1)**H
*
CALL ZGERC( LASTC, LASTV, -TAU, WORK, 1, V, INCV, C, LDC )
END IF
END IF
RETURN
*
* End of ZLARF
*
END

774
lapack/zlarfb.f Normal file
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@@ -0,0 +1,774 @@
*> \brief \b ZLARFB
*
* =========== DOCUMENTATION ===========
*
* Online html documentation available at
* http://www.netlib.org/lapack/explore-html/
*
*> \htmlonly
*> Download ZLARFB + dependencies
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/zlarfb.f">
*> [TGZ]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/zlarfb.f">
*> [ZIP]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/zlarfb.f">
*> [TXT]</a>
*> \endhtmlonly
*
* Definition:
* ===========
*
* SUBROUTINE ZLARFB( SIDE, TRANS, DIRECT, STOREV, M, N, K, V, LDV,
* T, LDT, C, LDC, WORK, LDWORK )
*
* .. Scalar Arguments ..
* CHARACTER DIRECT, SIDE, STOREV, TRANS
* INTEGER K, LDC, LDT, LDV, LDWORK, M, N
* ..
* .. Array Arguments ..
* COMPLEX*16 C( LDC, * ), T( LDT, * ), V( LDV, * ),
* $ WORK( LDWORK, * )
* ..
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> ZLARFB applies a complex block reflector H or its transpose H**H to a
*> complex M-by-N matrix C, from either the left or the right.
*> \endverbatim
*
* Arguments:
* ==========
*
*> \param[in] SIDE
*> \verbatim
*> SIDE is CHARACTER*1
*> = 'L': apply H or H**H from the Left
*> = 'R': apply H or H**H from the Right
*> \endverbatim
*>
*> \param[in] TRANS
*> \verbatim
*> TRANS is CHARACTER*1
*> = 'N': apply H (No transpose)
*> = 'C': apply H**H (Conjugate transpose)
*> \endverbatim
*>
*> \param[in] DIRECT
*> \verbatim
*> DIRECT is CHARACTER*1
*> Indicates how H is formed from a product of elementary
*> reflectors
*> = 'F': H = H(1) H(2) . . . H(k) (Forward)
*> = 'B': H = H(k) . . . H(2) H(1) (Backward)
*> \endverbatim
*>
*> \param[in] STOREV
*> \verbatim
*> STOREV is CHARACTER*1
*> Indicates how the vectors which define the elementary
*> reflectors are stored:
*> = 'C': Columnwise
*> = 'R': Rowwise
*> \endverbatim
*>
*> \param[in] M
*> \verbatim
*> M is INTEGER
*> The number of rows of the matrix C.
*> \endverbatim
*>
*> \param[in] N
*> \verbatim
*> N is INTEGER
*> The number of columns of the matrix C.
*> \endverbatim
*>
*> \param[in] K
*> \verbatim
*> K is INTEGER
*> The order of the matrix T (= the number of elementary
*> reflectors whose product defines the block reflector).
*> \endverbatim
*>
*> \param[in] V
*> \verbatim
*> V is COMPLEX*16 array, dimension
*> (LDV,K) if STOREV = 'C'
*> (LDV,M) if STOREV = 'R' and SIDE = 'L'
*> (LDV,N) if STOREV = 'R' and SIDE = 'R'
*> See Further Details.
*> \endverbatim
*>
*> \param[in] LDV
*> \verbatim
*> LDV is INTEGER
*> The leading dimension of the array V.
*> If STOREV = 'C' and SIDE = 'L', LDV >= max(1,M);
*> if STOREV = 'C' and SIDE = 'R', LDV >= max(1,N);
*> if STOREV = 'R', LDV >= K.
*> \endverbatim
*>
*> \param[in] T
*> \verbatim
*> T is COMPLEX*16 array, dimension (LDT,K)
*> The triangular K-by-K matrix T in the representation of the
*> block reflector.
*> \endverbatim
*>
*> \param[in] LDT
*> \verbatim
*> LDT is INTEGER
*> The leading dimension of the array T. LDT >= K.
*> \endverbatim
*>
*> \param[in,out] C
*> \verbatim
*> C is COMPLEX*16 array, dimension (LDC,N)
*> On entry, the M-by-N matrix C.
*> On exit, C is overwritten by H*C or H**H*C or C*H or C*H**H.
*> \endverbatim
*>
*> \param[in] LDC
*> \verbatim
*> LDC is INTEGER
*> The leading dimension of the array C. LDC >= max(1,M).
*> \endverbatim
*>
*> \param[out] WORK
*> \verbatim
*> WORK is COMPLEX*16 array, dimension (LDWORK,K)
*> \endverbatim
*>
*> \param[in] LDWORK
*> \verbatim
*> LDWORK is INTEGER
*> The leading dimension of the array WORK.
*> If SIDE = 'L', LDWORK >= max(1,N);
*> if SIDE = 'R', LDWORK >= max(1,M).
*> \endverbatim
*
* Authors:
* ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \date November 2011
*
*> \ingroup complex16OTHERauxiliary
*
*> \par Further Details:
* =====================
*>
*> \verbatim
*>
*> The shape of the matrix V and the storage of the vectors which define
*> the H(i) is best illustrated by the following example with n = 5 and
*> k = 3. The elements equal to 1 are not stored; the corresponding
*> array elements are modified but restored on exit. The rest of the
*> array is not used.
*>
*> DIRECT = 'F' and STOREV = 'C': DIRECT = 'F' and STOREV = 'R':
*>
*> V = ( 1 ) V = ( 1 v1 v1 v1 v1 )
*> ( v1 1 ) ( 1 v2 v2 v2 )
*> ( v1 v2 1 ) ( 1 v3 v3 )
*> ( v1 v2 v3 )
*> ( v1 v2 v3 )
*>
*> DIRECT = 'B' and STOREV = 'C': DIRECT = 'B' and STOREV = 'R':
*>
*> V = ( v1 v2 v3 ) V = ( v1 v1 1 )
*> ( v1 v2 v3 ) ( v2 v2 v2 1 )
*> ( 1 v2 v3 ) ( v3 v3 v3 v3 1 )
*> ( 1 v3 )
*> ( 1 )
*> \endverbatim
*>
* =====================================================================
SUBROUTINE ZLARFB( SIDE, TRANS, DIRECT, STOREV, M, N, K, V, LDV,
$ T, LDT, C, LDC, WORK, LDWORK )
*
* -- LAPACK auxiliary routine (version 3.4.0) --
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
* November 2011
*
* .. Scalar Arguments ..
CHARACTER DIRECT, SIDE, STOREV, TRANS
INTEGER K, LDC, LDT, LDV, LDWORK, M, N
* ..
* .. Array Arguments ..
COMPLEX*16 C( LDC, * ), T( LDT, * ), V( LDV, * ),
$ WORK( LDWORK, * )
* ..
*
* =====================================================================
*
* .. Parameters ..
COMPLEX*16 ONE
PARAMETER ( ONE = ( 1.0D+0, 0.0D+0 ) )
* ..
* .. Local Scalars ..
CHARACTER TRANST
INTEGER I, J, LASTV, LASTC
* ..
* .. External Functions ..
LOGICAL LSAME
INTEGER ILAZLR, ILAZLC
EXTERNAL LSAME, ILAZLR, ILAZLC
* ..
* .. External Subroutines ..
EXTERNAL ZCOPY, ZGEMM, ZLACGV, ZTRMM
* ..
* .. Intrinsic Functions ..
INTRINSIC DCONJG
* ..
* .. Executable Statements ..
*
* Quick return if possible
*
IF( M.LE.0 .OR. N.LE.0 )
$ RETURN
*
IF( LSAME( TRANS, 'N' ) ) THEN
TRANST = 'C'
ELSE
TRANST = 'N'
END IF
*
IF( LSAME( STOREV, 'C' ) ) THEN
*
IF( LSAME( DIRECT, 'F' ) ) THEN
*
* Let V = ( V1 ) (first K rows)
* ( V2 )
* where V1 is unit lower triangular.
*
IF( LSAME( SIDE, 'L' ) ) THEN
*
* Form H * C or H**H * C where C = ( C1 )
* ( C2 )
*
LASTV = MAX( K, ILAZLR( M, K, V, LDV ) )
LASTC = ILAZLC( LASTV, N, C, LDC )
*
* W := C**H * V = (C1**H * V1 + C2**H * V2) (stored in WORK)
*
* W := C1**H
*
DO 10 J = 1, K
CALL ZCOPY( LASTC, C( J, 1 ), LDC, WORK( 1, J ), 1 )
CALL ZLACGV( LASTC, WORK( 1, J ), 1 )
10 CONTINUE
*
* W := W * V1
*
CALL ZTRMM( 'Right', 'Lower', 'No transpose', 'Unit',
$ LASTC, K, ONE, V, LDV, WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C2**H *V2
*
CALL ZGEMM( 'Conjugate transpose', 'No transpose',
$ LASTC, K, LASTV-K, ONE, C( K+1, 1 ), LDC,
$ V( K+1, 1 ), LDV, ONE, WORK, LDWORK )
END IF
*
* W := W * T**H or W * T
*
CALL ZTRMM( 'Right', 'Upper', TRANST, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - V * W**H
*
IF( M.GT.K ) THEN
*
* C2 := C2 - V2 * W**H
*
CALL ZGEMM( 'No transpose', 'Conjugate transpose',
$ LASTV-K, LASTC, K,
$ -ONE, V( K+1, 1 ), LDV, WORK, LDWORK,
$ ONE, C( K+1, 1 ), LDC )
END IF
*
* W := W * V1**H
*
CALL ZTRMM( 'Right', 'Lower', 'Conjugate transpose',
$ 'Unit', LASTC, K, ONE, V, LDV, WORK, LDWORK )
*
* C1 := C1 - W**H
*
DO 30 J = 1, K
DO 20 I = 1, LASTC
C( J, I ) = C( J, I ) - DCONJG( WORK( I, J ) )
20 CONTINUE
30 CONTINUE
*
ELSE IF( LSAME( SIDE, 'R' ) ) THEN
*
* Form C * H or C * H**H where C = ( C1 C2 )
*
LASTV = MAX( K, ILAZLR( N, K, V, LDV ) )
LASTC = ILAZLR( M, LASTV, C, LDC )
*
* W := C * V = (C1*V1 + C2*V2) (stored in WORK)
*
* W := C1
*
DO 40 J = 1, K
CALL ZCOPY( LASTC, C( 1, J ), 1, WORK( 1, J ), 1 )
40 CONTINUE
*
* W := W * V1
*
CALL ZTRMM( 'Right', 'Lower', 'No transpose', 'Unit',
$ LASTC, K, ONE, V, LDV, WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C2 * V2
*
CALL ZGEMM( 'No transpose', 'No transpose',
$ LASTC, K, LASTV-K,
$ ONE, C( 1, K+1 ), LDC, V( K+1, 1 ), LDV,
$ ONE, WORK, LDWORK )
END IF
*
* W := W * T or W * T**H
*
CALL ZTRMM( 'Right', 'Upper', TRANS, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - W * V**H
*
IF( LASTV.GT.K ) THEN
*
* C2 := C2 - W * V2**H
*
CALL ZGEMM( 'No transpose', 'Conjugate transpose',
$ LASTC, LASTV-K, K,
$ -ONE, WORK, LDWORK, V( K+1, 1 ), LDV,
$ ONE, C( 1, K+1 ), LDC )
END IF
*
* W := W * V1**H
*
CALL ZTRMM( 'Right', 'Lower', 'Conjugate transpose',
$ 'Unit', LASTC, K, ONE, V, LDV, WORK, LDWORK )
*
* C1 := C1 - W
*
DO 60 J = 1, K
DO 50 I = 1, LASTC
C( I, J ) = C( I, J ) - WORK( I, J )
50 CONTINUE
60 CONTINUE
END IF
*
ELSE
*
* Let V = ( V1 )
* ( V2 ) (last K rows)
* where V2 is unit upper triangular.
*
IF( LSAME( SIDE, 'L' ) ) THEN
*
* Form H * C or H**H * C where C = ( C1 )
* ( C2 )
*
LASTV = MAX( K, ILAZLR( M, K, V, LDV ) )
LASTC = ILAZLC( LASTV, N, C, LDC )
*
* W := C**H * V = (C1**H * V1 + C2**H * V2) (stored in WORK)
*
* W := C2**H
*
DO 70 J = 1, K
CALL ZCOPY( LASTC, C( LASTV-K+J, 1 ), LDC,
$ WORK( 1, J ), 1 )
CALL ZLACGV( LASTC, WORK( 1, J ), 1 )
70 CONTINUE
*
* W := W * V2
*
CALL ZTRMM( 'Right', 'Upper', 'No transpose', 'Unit',
$ LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
$ WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C1**H*V1
*
CALL ZGEMM( 'Conjugate transpose', 'No transpose',
$ LASTC, K, LASTV-K,
$ ONE, C, LDC, V, LDV,
$ ONE, WORK, LDWORK )
END IF
*
* W := W * T**H or W * T
*
CALL ZTRMM( 'Right', 'Lower', TRANST, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - V * W**H
*
IF( LASTV.GT.K ) THEN
*
* C1 := C1 - V1 * W**H
*
CALL ZGEMM( 'No transpose', 'Conjugate transpose',
$ LASTV-K, LASTC, K,
$ -ONE, V, LDV, WORK, LDWORK,
$ ONE, C, LDC )
END IF
*
* W := W * V2**H
*
CALL ZTRMM( 'Right', 'Upper', 'Conjugate transpose',
$ 'Unit', LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
$ WORK, LDWORK )
*
* C2 := C2 - W**H
*
DO 90 J = 1, K
DO 80 I = 1, LASTC
C( LASTV-K+J, I ) = C( LASTV-K+J, I ) -
$ DCONJG( WORK( I, J ) )
80 CONTINUE
90 CONTINUE
*
ELSE IF( LSAME( SIDE, 'R' ) ) THEN
*
* Form C * H or C * H**H where C = ( C1 C2 )
*
LASTV = MAX( K, ILAZLR( N, K, V, LDV ) )
LASTC = ILAZLR( M, LASTV, C, LDC )
*
* W := C * V = (C1*V1 + C2*V2) (stored in WORK)
*
* W := C2
*
DO 100 J = 1, K
CALL ZCOPY( LASTC, C( 1, LASTV-K+J ), 1,
$ WORK( 1, J ), 1 )
100 CONTINUE
*
* W := W * V2
*
CALL ZTRMM( 'Right', 'Upper', 'No transpose', 'Unit',
$ LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
$ WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C1 * V1
*
CALL ZGEMM( 'No transpose', 'No transpose',
$ LASTC, K, LASTV-K,
$ ONE, C, LDC, V, LDV, ONE, WORK, LDWORK )
END IF
*
* W := W * T or W * T**H
*
CALL ZTRMM( 'Right', 'Lower', TRANS, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - W * V**H
*
IF( LASTV.GT.K ) THEN
*
* C1 := C1 - W * V1**H
*
CALL ZGEMM( 'No transpose', 'Conjugate transpose',
$ LASTC, LASTV-K, K, -ONE, WORK, LDWORK, V, LDV,
$ ONE, C, LDC )
END IF
*
* W := W * V2**H
*
CALL ZTRMM( 'Right', 'Upper', 'Conjugate transpose',
$ 'Unit', LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
$ WORK, LDWORK )
*
* C2 := C2 - W
*
DO 120 J = 1, K
DO 110 I = 1, LASTC
C( I, LASTV-K+J ) = C( I, LASTV-K+J )
$ - WORK( I, J )
110 CONTINUE
120 CONTINUE
END IF
END IF
*
ELSE IF( LSAME( STOREV, 'R' ) ) THEN
*
IF( LSAME( DIRECT, 'F' ) ) THEN
*
* Let V = ( V1 V2 ) (V1: first K columns)
* where V1 is unit upper triangular.
*
IF( LSAME( SIDE, 'L' ) ) THEN
*
* Form H * C or H**H * C where C = ( C1 )
* ( C2 )
*
LASTV = MAX( K, ILAZLC( K, M, V, LDV ) )
LASTC = ILAZLC( LASTV, N, C, LDC )
*
* W := C**H * V**H = (C1**H * V1**H + C2**H * V2**H) (stored in WORK)
*
* W := C1**H
*
DO 130 J = 1, K
CALL ZCOPY( LASTC, C( J, 1 ), LDC, WORK( 1, J ), 1 )
CALL ZLACGV( LASTC, WORK( 1, J ), 1 )
130 CONTINUE
*
* W := W * V1**H
*
CALL ZTRMM( 'Right', 'Upper', 'Conjugate transpose',
$ 'Unit', LASTC, K, ONE, V, LDV, WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C2**H*V2**H
*
CALL ZGEMM( 'Conjugate transpose',
$ 'Conjugate transpose', LASTC, K, LASTV-K,
$ ONE, C( K+1, 1 ), LDC, V( 1, K+1 ), LDV,
$ ONE, WORK, LDWORK )
END IF
*
* W := W * T**H or W * T
*
CALL ZTRMM( 'Right', 'Upper', TRANST, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - V**H * W**H
*
IF( LASTV.GT.K ) THEN
*
* C2 := C2 - V2**H * W**H
*
CALL ZGEMM( 'Conjugate transpose',
$ 'Conjugate transpose', LASTV-K, LASTC, K,
$ -ONE, V( 1, K+1 ), LDV, WORK, LDWORK,
$ ONE, C( K+1, 1 ), LDC )
END IF
*
* W := W * V1
*
CALL ZTRMM( 'Right', 'Upper', 'No transpose', 'Unit',
$ LASTC, K, ONE, V, LDV, WORK, LDWORK )
*
* C1 := C1 - W**H
*
DO 150 J = 1, K
DO 140 I = 1, LASTC
C( J, I ) = C( J, I ) - DCONJG( WORK( I, J ) )
140 CONTINUE
150 CONTINUE
*
ELSE IF( LSAME( SIDE, 'R' ) ) THEN
*
* Form C * H or C * H**H where C = ( C1 C2 )
*
LASTV = MAX( K, ILAZLC( K, N, V, LDV ) )
LASTC = ILAZLR( M, LASTV, C, LDC )
*
* W := C * V**H = (C1*V1**H + C2*V2**H) (stored in WORK)
*
* W := C1
*
DO 160 J = 1, K
CALL ZCOPY( LASTC, C( 1, J ), 1, WORK( 1, J ), 1 )
160 CONTINUE
*
* W := W * V1**H
*
CALL ZTRMM( 'Right', 'Upper', 'Conjugate transpose',
$ 'Unit', LASTC, K, ONE, V, LDV, WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C2 * V2**H
*
CALL ZGEMM( 'No transpose', 'Conjugate transpose',
$ LASTC, K, LASTV-K, ONE, C( 1, K+1 ), LDC,
$ V( 1, K+1 ), LDV, ONE, WORK, LDWORK )
END IF
*
* W := W * T or W * T**H
*
CALL ZTRMM( 'Right', 'Upper', TRANS, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - W * V
*
IF( LASTV.GT.K ) THEN
*
* C2 := C2 - W * V2
*
CALL ZGEMM( 'No transpose', 'No transpose',
$ LASTC, LASTV-K, K,
$ -ONE, WORK, LDWORK, V( 1, K+1 ), LDV,
$ ONE, C( 1, K+1 ), LDC )
END IF
*
* W := W * V1
*
CALL ZTRMM( 'Right', 'Upper', 'No transpose', 'Unit',
$ LASTC, K, ONE, V, LDV, WORK, LDWORK )
*
* C1 := C1 - W
*
DO 180 J = 1, K
DO 170 I = 1, LASTC
C( I, J ) = C( I, J ) - WORK( I, J )
170 CONTINUE
180 CONTINUE
*
END IF
*
ELSE
*
* Let V = ( V1 V2 ) (V2: last K columns)
* where V2 is unit lower triangular.
*
IF( LSAME( SIDE, 'L' ) ) THEN
*
* Form H * C or H**H * C where C = ( C1 )
* ( C2 )
*
LASTV = MAX( K, ILAZLC( K, M, V, LDV ) )
LASTC = ILAZLC( LASTV, N, C, LDC )
*
* W := C**H * V**H = (C1**H * V1**H + C2**H * V2**H) (stored in WORK)
*
* W := C2**H
*
DO 190 J = 1, K
CALL ZCOPY( LASTC, C( LASTV-K+J, 1 ), LDC,
$ WORK( 1, J ), 1 )
CALL ZLACGV( LASTC, WORK( 1, J ), 1 )
190 CONTINUE
*
* W := W * V2**H
*
CALL ZTRMM( 'Right', 'Lower', 'Conjugate transpose',
$ 'Unit', LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV,
$ WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C1**H * V1**H
*
CALL ZGEMM( 'Conjugate transpose',
$ 'Conjugate transpose', LASTC, K, LASTV-K,
$ ONE, C, LDC, V, LDV, ONE, WORK, LDWORK )
END IF
*
* W := W * T**H or W * T
*
CALL ZTRMM( 'Right', 'Lower', TRANST, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - V**H * W**H
*
IF( LASTV.GT.K ) THEN
*
* C1 := C1 - V1**H * W**H
*
CALL ZGEMM( 'Conjugate transpose',
$ 'Conjugate transpose', LASTV-K, LASTC, K,
$ -ONE, V, LDV, WORK, LDWORK, ONE, C, LDC )
END IF
*
* W := W * V2
*
CALL ZTRMM( 'Right', 'Lower', 'No transpose', 'Unit',
$ LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV,
$ WORK, LDWORK )
*
* C2 := C2 - W**H
*
DO 210 J = 1, K
DO 200 I = 1, LASTC
C( LASTV-K+J, I ) = C( LASTV-K+J, I ) -
$ DCONJG( WORK( I, J ) )
200 CONTINUE
210 CONTINUE
*
ELSE IF( LSAME( SIDE, 'R' ) ) THEN
*
* Form C * H or C * H**H where C = ( C1 C2 )
*
LASTV = MAX( K, ILAZLC( K, N, V, LDV ) )
LASTC = ILAZLR( M, LASTV, C, LDC )
*
* W := C * V**H = (C1*V1**H + C2*V2**H) (stored in WORK)
*
* W := C2
*
DO 220 J = 1, K
CALL ZCOPY( LASTC, C( 1, LASTV-K+J ), 1,
$ WORK( 1, J ), 1 )
220 CONTINUE
*
* W := W * V2**H
*
CALL ZTRMM( 'Right', 'Lower', 'Conjugate transpose',
$ 'Unit', LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV,
$ WORK, LDWORK )
IF( LASTV.GT.K ) THEN
*
* W := W + C1 * V1**H
*
CALL ZGEMM( 'No transpose', 'Conjugate transpose',
$ LASTC, K, LASTV-K, ONE, C, LDC, V, LDV, ONE,
$ WORK, LDWORK )
END IF
*
* W := W * T or W * T**H
*
CALL ZTRMM( 'Right', 'Lower', TRANS, 'Non-unit',
$ LASTC, K, ONE, T, LDT, WORK, LDWORK )
*
* C := C - W * V
*
IF( LASTV.GT.K ) THEN
*
* C1 := C1 - W * V1
*
CALL ZGEMM( 'No transpose', 'No transpose',
$ LASTC, LASTV-K, K, -ONE, WORK, LDWORK, V, LDV,
$ ONE, C, LDC )
END IF
*
* W := W * V2
*
CALL ZTRMM( 'Right', 'Lower', 'No transpose', 'Unit',
$ LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV,
$ WORK, LDWORK )
*
* C1 := C1 - W
*
DO 240 J = 1, K
DO 230 I = 1, LASTC
C( I, LASTV-K+J ) = C( I, LASTV-K+J )
$ - WORK( I, J )
230 CONTINUE
240 CONTINUE
*
END IF
*
END IF
END IF
*
RETURN
*
* End of ZLARFB
*
END

203
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*> \brief \b ZLARFG
*
* =========== DOCUMENTATION ===========
*
* Online html documentation available at
* http://www.netlib.org/lapack/explore-html/
*
*> \htmlonly
*> Download ZLARFG + dependencies
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/zlarfg.f">
*> [TGZ]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/zlarfg.f">
*> [ZIP]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/zlarfg.f">
*> [TXT]</a>
*> \endhtmlonly
*
* Definition:
* ===========
*
* SUBROUTINE ZLARFG( N, ALPHA, X, INCX, TAU )
*
* .. Scalar Arguments ..
* INTEGER INCX, N
* COMPLEX*16 ALPHA, TAU
* ..
* .. Array Arguments ..
* COMPLEX*16 X( * )
* ..
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> ZLARFG generates a complex elementary reflector H of order n, such
*> that
*>
*> H**H * ( alpha ) = ( beta ), H**H * H = I.
*> ( x ) ( 0 )
*>
*> where alpha and beta are scalars, with beta real, and x is an
*> (n-1)-element complex vector. H is represented in the form
*>
*> H = I - tau * ( 1 ) * ( 1 v**H ) ,
*> ( v )
*>
*> where tau is a complex scalar and v is a complex (n-1)-element
*> vector. Note that H is not hermitian.
*>
*> If the elements of x are all zero and alpha is real, then tau = 0
*> and H is taken to be the unit matrix.
*>
*> Otherwise 1 <= real(tau) <= 2 and abs(tau-1) <= 1 .
*> \endverbatim
*
* Arguments:
* ==========
*
*> \param[in] N
*> \verbatim
*> N is INTEGER
*> The order of the elementary reflector.
*> \endverbatim
*>
*> \param[in,out] ALPHA
*> \verbatim
*> ALPHA is COMPLEX*16
*> On entry, the value alpha.
*> On exit, it is overwritten with the value beta.
*> \endverbatim
*>
*> \param[in,out] X
*> \verbatim
*> X is COMPLEX*16 array, dimension
*> (1+(N-2)*abs(INCX))
*> On entry, the vector x.
*> On exit, it is overwritten with the vector v.
*> \endverbatim
*>
*> \param[in] INCX
*> \verbatim
*> INCX is INTEGER
*> The increment between elements of X. INCX > 0.
*> \endverbatim
*>
*> \param[out] TAU
*> \verbatim
*> TAU is COMPLEX*16
*> The value tau.
*> \endverbatim
*
* Authors:
* ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \date November 2011
*
*> \ingroup complex16OTHERauxiliary
*
* =====================================================================
SUBROUTINE ZLARFG( N, ALPHA, X, INCX, TAU )
*
* -- LAPACK auxiliary routine (version 3.4.0) --
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
* November 2011
*
* .. Scalar Arguments ..
INTEGER INCX, N
COMPLEX*16 ALPHA, TAU
* ..
* .. Array Arguments ..
COMPLEX*16 X( * )
* ..
*
* =====================================================================
*
* .. Parameters ..
DOUBLE PRECISION ONE, ZERO
PARAMETER ( ONE = 1.0D+0, ZERO = 0.0D+0 )
* ..
* .. Local Scalars ..
INTEGER J, KNT
DOUBLE PRECISION ALPHI, ALPHR, BETA, RSAFMN, SAFMIN, XNORM
* ..
* .. External Functions ..
DOUBLE PRECISION DLAMCH, DLAPY3, DZNRM2
COMPLEX*16 ZLADIV
EXTERNAL DLAMCH, DLAPY3, DZNRM2, ZLADIV
* ..
* .. Intrinsic Functions ..
INTRINSIC ABS, DBLE, DCMPLX, DIMAG, SIGN
* ..
* .. External Subroutines ..
EXTERNAL ZDSCAL, ZSCAL
* ..
* .. Executable Statements ..
*
IF( N.LE.0 ) THEN
TAU = ZERO
RETURN
END IF
*
XNORM = DZNRM2( N-1, X, INCX )
ALPHR = DBLE( ALPHA )
ALPHI = DIMAG( ALPHA )
*
IF( XNORM.EQ.ZERO .AND. ALPHI.EQ.ZERO ) THEN
*
* H = I
*
TAU = ZERO
ELSE
*
* general case
*
BETA = -SIGN( DLAPY3( ALPHR, ALPHI, XNORM ), ALPHR )
SAFMIN = DLAMCH( 'S' ) / DLAMCH( 'E' )
RSAFMN = ONE / SAFMIN
*
KNT = 0
IF( ABS( BETA ).LT.SAFMIN ) THEN
*
* XNORM, BETA may be inaccurate; scale X and recompute them
*
10 CONTINUE
KNT = KNT + 1
CALL ZDSCAL( N-1, RSAFMN, X, INCX )
BETA = BETA*RSAFMN
ALPHI = ALPHI*RSAFMN
ALPHR = ALPHR*RSAFMN
IF( ABS( BETA ).LT.SAFMIN )
$ GO TO 10
*
* New BETA is at most 1, at least SAFMIN
*
XNORM = DZNRM2( N-1, X, INCX )
ALPHA = DCMPLX( ALPHR, ALPHI )
BETA = -SIGN( DLAPY3( ALPHR, ALPHI, XNORM ), ALPHR )
END IF
TAU = DCMPLX( ( BETA-ALPHR ) / BETA, -ALPHI / BETA )
ALPHA = ZLADIV( DCMPLX( ONE ), ALPHA-BETA )
CALL ZSCAL( N-1, ALPHA, X, INCX )
*
* If ALPHA is subnormal, it may lose relative accuracy
*
DO 20 J = 1, KNT
BETA = BETA*SAFMIN
20 CONTINUE
ALPHA = BETA
END IF
*
RETURN
*
* End of ZLARFG
*
END

327
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*> \brief \b ZLARFT
*
* =========== DOCUMENTATION ===========
*
* Online html documentation available at
* http://www.netlib.org/lapack/explore-html/
*
*> \htmlonly
*> Download ZLARFT + dependencies
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/zlarft.f">
*> [TGZ]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/zlarft.f">
*> [ZIP]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/zlarft.f">
*> [TXT]</a>
*> \endhtmlonly
*
* Definition:
* ===========
*
* SUBROUTINE ZLARFT( DIRECT, STOREV, N, K, V, LDV, TAU, T, LDT )
*
* .. Scalar Arguments ..
* CHARACTER DIRECT, STOREV
* INTEGER K, LDT, LDV, N
* ..
* .. Array Arguments ..
* COMPLEX*16 T( LDT, * ), TAU( * ), V( LDV, * )
* ..
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> ZLARFT forms the triangular factor T of a complex block reflector H
*> of order n, which is defined as a product of k elementary reflectors.
*>
*> If DIRECT = 'F', H = H(1) H(2) . . . H(k) and T is upper triangular;
*>
*> If DIRECT = 'B', H = H(k) . . . H(2) H(1) and T is lower triangular.
*>
*> If STOREV = 'C', the vector which defines the elementary reflector
*> H(i) is stored in the i-th column of the array V, and
*>
*> H = I - V * T * V**H
*>
*> If STOREV = 'R', the vector which defines the elementary reflector
*> H(i) is stored in the i-th row of the array V, and
*>
*> H = I - V**H * T * V
*> \endverbatim
*
* Arguments:
* ==========
*
*> \param[in] DIRECT
*> \verbatim
*> DIRECT is CHARACTER*1
*> Specifies the order in which the elementary reflectors are
*> multiplied to form the block reflector:
*> = 'F': H = H(1) H(2) . . . H(k) (Forward)
*> = 'B': H = H(k) . . . H(2) H(1) (Backward)
*> \endverbatim
*>
*> \param[in] STOREV
*> \verbatim
*> STOREV is CHARACTER*1
*> Specifies how the vectors which define the elementary
*> reflectors are stored (see also Further Details):
*> = 'C': columnwise
*> = 'R': rowwise
*> \endverbatim
*>
*> \param[in] N
*> \verbatim
*> N is INTEGER
*> The order of the block reflector H. N >= 0.
*> \endverbatim
*>
*> \param[in] K
*> \verbatim
*> K is INTEGER
*> The order of the triangular factor T (= the number of
*> elementary reflectors). K >= 1.
*> \endverbatim
*>
*> \param[in] V
*> \verbatim
*> V is COMPLEX*16 array, dimension
*> (LDV,K) if STOREV = 'C'
*> (LDV,N) if STOREV = 'R'
*> The matrix V. See further details.
*> \endverbatim
*>
*> \param[in] LDV
*> \verbatim
*> LDV is INTEGER
*> The leading dimension of the array V.
*> If STOREV = 'C', LDV >= max(1,N); if STOREV = 'R', LDV >= K.
*> \endverbatim
*>
*> \param[in] TAU
*> \verbatim
*> TAU is COMPLEX*16 array, dimension (K)
*> TAU(i) must contain the scalar factor of the elementary
*> reflector H(i).
*> \endverbatim
*>
*> \param[out] T
*> \verbatim
*> T is COMPLEX*16 array, dimension (LDT,K)
*> The k by k triangular factor T of the block reflector.
*> If DIRECT = 'F', T is upper triangular; if DIRECT = 'B', T is
*> lower triangular. The rest of the array is not used.
*> \endverbatim
*>
*> \param[in] LDT
*> \verbatim
*> LDT is INTEGER
*> The leading dimension of the array T. LDT >= K.
*> \endverbatim
*
* Authors:
* ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \date April 2012
*
*> \ingroup complex16OTHERauxiliary
*
*> \par Further Details:
* =====================
*>
*> \verbatim
*>
*> The shape of the matrix V and the storage of the vectors which define
*> the H(i) is best illustrated by the following example with n = 5 and
*> k = 3. The elements equal to 1 are not stored.
*>
*> DIRECT = 'F' and STOREV = 'C': DIRECT = 'F' and STOREV = 'R':
*>
*> V = ( 1 ) V = ( 1 v1 v1 v1 v1 )
*> ( v1 1 ) ( 1 v2 v2 v2 )
*> ( v1 v2 1 ) ( 1 v3 v3 )
*> ( v1 v2 v3 )
*> ( v1 v2 v3 )
*>
*> DIRECT = 'B' and STOREV = 'C': DIRECT = 'B' and STOREV = 'R':
*>
*> V = ( v1 v2 v3 ) V = ( v1 v1 1 )
*> ( v1 v2 v3 ) ( v2 v2 v2 1 )
*> ( 1 v2 v3 ) ( v3 v3 v3 v3 1 )
*> ( 1 v3 )
*> ( 1 )
*> \endverbatim
*>
* =====================================================================
SUBROUTINE ZLARFT( DIRECT, STOREV, N, K, V, LDV, TAU, T, LDT )
*
* -- LAPACK auxiliary routine (version 3.4.1) --
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
* April 2012
*
* .. Scalar Arguments ..
CHARACTER DIRECT, STOREV
INTEGER K, LDT, LDV, N
* ..
* .. Array Arguments ..
COMPLEX*16 T( LDT, * ), TAU( * ), V( LDV, * )
* ..
*
* =====================================================================
*
* .. Parameters ..
COMPLEX*16 ONE, ZERO
PARAMETER ( ONE = ( 1.0D+0, 0.0D+0 ),
$ ZERO = ( 0.0D+0, 0.0D+0 ) )
* ..
* .. Local Scalars ..
INTEGER I, J, PREVLASTV, LASTV
* ..
* .. External Subroutines ..
EXTERNAL ZGEMV, ZLACGV, ZTRMV
* ..
* .. External Functions ..
LOGICAL LSAME
EXTERNAL LSAME
* ..
* .. Executable Statements ..
*
* Quick return if possible
*
IF( N.EQ.0 )
$ RETURN
*
IF( LSAME( DIRECT, 'F' ) ) THEN
PREVLASTV = N
DO I = 1, K
PREVLASTV = MAX( PREVLASTV, I )
IF( TAU( I ).EQ.ZERO ) THEN
*
* H(i) = I
*
DO J = 1, I
T( J, I ) = ZERO
END DO
ELSE
*
* general case
*
IF( LSAME( STOREV, 'C' ) ) THEN
* Skip any trailing zeros.
DO LASTV = N, I+1, -1
IF( V( LASTV, I ).NE.ZERO ) EXIT
END DO
DO J = 1, I-1
T( J, I ) = -TAU( I ) * CONJG( V( I , J ) )
END DO
J = MIN( LASTV, PREVLASTV )
*
* T(1:i-1,i) := - tau(i) * V(i:j,1:i-1)**H * V(i:j,i)
*
CALL ZGEMV( 'Conjugate transpose', J-I, I-1,
$ -TAU( I ), V( I+1, 1 ), LDV,
$ V( I+1, I ), 1, ONE, T( 1, I ), 1 )
ELSE
* Skip any trailing zeros.
DO LASTV = N, I+1, -1
IF( V( I, LASTV ).NE.ZERO ) EXIT
END DO
DO J = 1, I-1
T( J, I ) = -TAU( I ) * V( J , I )
END DO
J = MIN( LASTV, PREVLASTV )
*
* T(1:i-1,i) := - tau(i) * V(1:i-1,i:j) * V(i,i:j)**H
*
CALL ZGEMM( 'N', 'C', I-1, 1, J-I, -TAU( I ),
$ V( 1, I+1 ), LDV, V( I, I+1 ), LDV,
$ ONE, T( 1, I ), LDT )
END IF
*
* T(1:i-1,i) := T(1:i-1,1:i-1) * T(1:i-1,i)
*
CALL ZTRMV( 'Upper', 'No transpose', 'Non-unit', I-1, T,
$ LDT, T( 1, I ), 1 )
T( I, I ) = TAU( I )
IF( I.GT.1 ) THEN
PREVLASTV = MAX( PREVLASTV, LASTV )
ELSE
PREVLASTV = LASTV
END IF
END IF
END DO
ELSE
PREVLASTV = 1
DO I = K, 1, -1
IF( TAU( I ).EQ.ZERO ) THEN
*
* H(i) = I
*
DO J = I, K
T( J, I ) = ZERO
END DO
ELSE
*
* general case
*
IF( I.LT.K ) THEN
IF( LSAME( STOREV, 'C' ) ) THEN
* Skip any leading zeros.
DO LASTV = 1, I-1
IF( V( LASTV, I ).NE.ZERO ) EXIT
END DO
DO J = I+1, K
T( J, I ) = -TAU( I ) * CONJG( V( N-K+I , J ) )
END DO
J = MAX( LASTV, PREVLASTV )
*
* T(i+1:k,i) = -tau(i) * V(j:n-k+i,i+1:k)**H * V(j:n-k+i,i)
*
CALL ZGEMV( 'Conjugate transpose', N-K+I-J, K-I,
$ -TAU( I ), V( J, I+1 ), LDV, V( J, I ),
$ 1, ONE, T( I+1, I ), 1 )
ELSE
* Skip any leading zeros.
DO LASTV = 1, I-1
IF( V( I, LASTV ).NE.ZERO ) EXIT
END DO
DO J = I+1, K
T( J, I ) = -TAU( I ) * V( J, N-K+I )
END DO
J = MAX( LASTV, PREVLASTV )
*
* T(i+1:k,i) = -tau(i) * V(i+1:k,j:n-k+i) * V(i,j:n-k+i)**H
*
CALL ZGEMM( 'N', 'C', K-I, 1, N-K+I-J, -TAU( I ),
$ V( I+1, J ), LDV, V( I, J ), LDV,
$ ONE, T( I+1, I ), LDT )
END IF
*
* T(i+1:k,i) := T(i+1:k,i+1:k) * T(i+1:k,i)
*
CALL ZTRMV( 'Lower', 'No transpose', 'Non-unit', K-I,
$ T( I+1, I+1 ), LDT, T( I+1, I ), 1 )
IF( I.GT.1 ) THEN
PREVLASTV = MIN( PREVLASTV, LASTV )
ELSE
PREVLASTV = LASTV
END IF
END IF
T( I, I ) = TAU( I )
END IF
END DO
END IF
RETURN
*
* End of ZLARFT
*
END