mirror of
https://gitlab.com/libeigen/eigen.git
synced 2026-04-10 11:34:33 +08:00
Eliminate and prune columns in a panel
This commit is contained in:
Desire NUENTSA
152
Eigen/src/SparseLU/SparseLU_pruneL.h
Normal file
152
Eigen/src/SparseLU/SparseLU_pruneL.h
Normal file
@@ -0,0 +1,152 @@
|
||||
// This file is part of Eigen, a lightweight C++ template library
|
||||
// for linear algebra.
|
||||
//
|
||||
// Copyright (C) 2012 Désiré Nuentsa-Wakam <desire.nuentsa_wakam@inria.fr>
|
||||
//
|
||||
// Eigen is free software; you can redistribute it and/or
|
||||
// modify it under the terms of the GNU Lesser General Public
|
||||
// License as published by the Free Software Foundation; either
|
||||
// version 3 of the License, or (at your option) any later version.
|
||||
//
|
||||
// Alternatively, you can redistribute it and/or
|
||||
// modify it under the terms of the GNU General Public License as
|
||||
// published by the Free Software Foundation; either version 2 of
|
||||
// the License, or (at your option) any later version.
|
||||
//
|
||||
// Eigen is distributed in the hope that it will be useful, but WITHOUT ANY
|
||||
// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
|
||||
// FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License or the
|
||||
// GNU General Public License for more details.
|
||||
//
|
||||
// You should have received a copy of the GNU Lesser General Public
|
||||
// License and a copy of the GNU General Public License along with
|
||||
// Eigen. If not, see <http://www.gnu.org/licenses/>.
|
||||
|
||||
/*
|
||||
|
||||
* NOTE: This file is the modified version of xpruneL.c file in SuperLU
|
||||
|
||||
* -- SuperLU routine (version 2.0) --
|
||||
* Univ. of California Berkeley, Xerox Palo Alto Research Center,
|
||||
* and Lawrence Berkeley National Lab.
|
||||
* November 15, 1997
|
||||
*
|
||||
* Copyright (c) 1994 by Xerox Corporation. All rights reserved.
|
||||
*
|
||||
* THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY
|
||||
* EXPRESSED OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
|
||||
*
|
||||
* Permission is hereby granted to use or copy this program for any
|
||||
* purpose, provided the above notices are retained on all copies.
|
||||
* Permission to modify the code and to distribute modified code is
|
||||
* granted, provided the above notices are retained, and a notice that
|
||||
* the code was modified is included with the above copyright notice.
|
||||
*/
|
||||
#ifndef SPARSELU_PRUNEL_H
|
||||
#define SPARSELU_PRUNEL_H
|
||||
/**
|
||||
* \brief Prunes the L-structure.
|
||||
*
|
||||
* It prunes the L-structure of supernodes whose L-structure constains the current pivot row "pivrow"
|
||||
*
|
||||
*
|
||||
* \param jcol The current column of L
|
||||
* \param [in]perm_r Row permutation
|
||||
* \param [out]pivrow The pivot row
|
||||
* \param nseg Number of segments ???
|
||||
* \param segrep
|
||||
* \param repfnz
|
||||
* \param [out]xprune
|
||||
* \param Glu Global LU data
|
||||
*
|
||||
*/
|
||||
template <typename VectorType>
|
||||
void SparseLU::LU_pruneL(const int jcol, const VectorXi& perm_r, const int pivrow, const int nseg, const VectorXi& segrep, VectorXi& repfnz, VectorXi& xprune, GlobalLU_t& Glu)
|
||||
{
|
||||
// Initialize pointers
|
||||
VectorXi& xsup = Glu.xsup;
|
||||
VectorXi& supno = Glu.supno;
|
||||
VectorXi& lsub = Glu.lsub;
|
||||
VectorXi& xlsub = Glu.xlsub;
|
||||
VectorType& lusup = Glu.lusup;
|
||||
VectorXi& xlusup = Glu.xlusup;
|
||||
|
||||
// For each supernode-rep irep in U(*,j]
|
||||
int jsupno = supno(jcol);
|
||||
int i,irep,irep1;
|
||||
bool movnum, do_prune = false;
|
||||
int kmin, kmax, ktemp, minloc, maxloc;
|
||||
for (i = 0; i < nseg; i++)
|
||||
{
|
||||
irep = segrep(i);
|
||||
irep1 = irep + 1;
|
||||
do_prune = false;
|
||||
|
||||
// Don't prune with a zero U-segment
|
||||
if (repfnz(irep) == IND_EMPTY) continue;
|
||||
|
||||
// If a snode overlaps with the next panel, then the U-segment
|
||||
// is fragmented into two parts -- irep and irep1. We should let
|
||||
// pruning occur at the rep-column in irep1s snode.
|
||||
if (supno(irep) == supno(irep1) continue; // don't prune
|
||||
|
||||
// If it has not been pruned & it has a nonz in row L(pivrow,i)
|
||||
if (supno(irep) != jsupno )
|
||||
{
|
||||
if ( xprune (irep) >= xlsub(irep1)
|
||||
{
|
||||
kmin = xlsub(irep);
|
||||
kmax = xlsub(irep1) - 1;
|
||||
for (krow = kmin; krow <= kmax; krow++)
|
||||
{
|
||||
if (lsub(krow) == pivrow)
|
||||
{
|
||||
do_prune = true;
|
||||
break;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
if (do_prune)
|
||||
{
|
||||
// do a quicksort-type partition
|
||||
// movnum=true means that the num values have to be exchanged
|
||||
movnum = false;
|
||||
if (irep == xsup(supno(irep)) ) // Snode of size 1
|
||||
movnum = true;
|
||||
|
||||
while (kmin <= kmax)
|
||||
{
|
||||
if (perm_r(lsub(kmax)) == IND_EMPTY)
|
||||
kmax--;
|
||||
else if ( perm_r(lsub(kmin)) != IND_EMPTY)
|
||||
kmin--;
|
||||
else
|
||||
{
|
||||
// kmin below pivrow (not yet pivoted), and kmax
|
||||
// above pivrow: interchange the two suscripts
|
||||
ktemp = lsub(kmin);
|
||||
lsub(kmin) = lsub(kmax);
|
||||
lsub(kmax) = ktemp;
|
||||
|
||||
// If the supernode has only one column, then we
|
||||
// only keep one set of subscripts. For any subscript
|
||||
// intercnahge performed, similar interchange must be
|
||||
// done on the numerical values.
|
||||
if (movnum)
|
||||
{
|
||||
minloc = xlusup(irep) + ( kmin - xlsub(irep) );
|
||||
maxloc = xlusup(irep) + ( kmax - xlsub(irep) );
|
||||
std::swap(lusup(minloc), lusup(maxloc));
|
||||
}
|
||||
kmin++;
|
||||
kmax--;
|
||||
}
|
||||
} // end while
|
||||
|
||||
xprune(irep) = kmin;
|
||||
} // end if do_prune
|
||||
} // end pruning
|
||||
} // End for each U-segment
|
||||
}
|
||||
#endif
|
||||
Reference in New Issue
Block a user