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Symbolic and numeric updates within the panel

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Desire NUENTSA
2012-05-30 18:09:26 +02:00
parent 8ab820b5b8
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Eigen/src/SparseLU/SparseLU_column_dfs.h Normal file
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// 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 xcolumn_dfs.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_COLUMN_DFS_H
#define SPARSELU_COLUMN_DFS_H
/**
* \brief Performs a symbolic factorization on column jcol and decide the supernode boundary
*
* A supernode representative is the last column of a supernode.
* The nonzeros in U[*,j] are segments that end at supernodes representatives.
* The routine returns a list of the supernodal representatives
* in topological order of the dfs that generates them.
* The location of the first nonzero in each supernodal segment
* (supernodal entry location) is also returned.
*
* \param m number of rows in the matrix
* \param jcol Current column
* \param perm_r Row permutation
* \param [in,out] nseg Number of segments in current U[*,j] - new segments appended
* \param lsub_col defines the rhs vector to start the dfs
* \param [in,out] segrep Segment representatives - new segments appended
* \param repfnz
* \param xprune
* \param marker
* \param parent
* \param xplore
* \param Glu global LU data
* \return 0 success
* > 0 number of bytes allocated when run out of space
*
*/
int SparseLU::LU_column_dfs(const int m, const int jcol, VectorXi& perm_r, VectorXi& nseg VectorXi& lsub_col, VectorXi& segrep, VectorXi& repfnz, VectorXi& xprune, VectorXi& marker, VectorXi& parent, VectorXi& xplore, LU_GlobalLu_t& Glu)
{
typedef typename VectorXi::Index;
int jcolp1, jcolm1, jsuper, nsuper, nextl;
int krow; // Row index of the current element
int kperm; // permuted row index
int krep; // Supernode reprentative of the current row
int k, kmark;
int chperm, chmark, chrep, oldrep, kchild;
int myfnz; // First nonzero element in the current column
int xdfs, maxdfs, kpar;
// Initialize pointers
VectorXi& xsup = Glu.xsup;
VectorXi& supno = Glu.supno;
VectorXi& lsub = Glu.lsub;
VectorXi& xlsub = Glu.xlsub;
nsuper = supno(jcol);
jsuper = nsuper;
nextl = xlsup(jcol);
VectorBlock<VectorXi> marker2(marker, 2*m, m);
// For each nonzero in A(*,jcol) do dfs
for (k = 0; lsub_col[k] != IND_EMPTY; k++)
{
krow = lsub_col(k);
lsub_col(k) = IND_EMPTY;
kmark = marker2(krow);
// krow was visited before, go to the next nonz;
if (kmark == jcol) continue;
// For each unmarker nbr krow of jcol
// krow is in L: place it in structure of L(*,jcol)
marker2(krow) = jcol;
kperm = perm_r(krow);
if (kperm == IND_EMPTY )
{
lsub(nextl++) = krow; // krow is indexed into A
if ( nextl >= nzlmax )
{
Glu.lsub = LUMemXpand<Index>(jcol, nextl, LSUB, nzlmax);
//FIXME try... catch out of space
Glu.nzlmax = nzlmax;
lsub = Glu.lsub;
}
if (kmark != jcolm1) jsuper = IND_EMPTY; // Row index subset testing
}
else
{
// krow is in U : if its supernode-rep krep
// has been explored, update repfnz(*)
krep = xsup(supno(kperm)+1) - 1;
myfnz = repfnz(krep);
if (myfnz != IND_EMPTY )
{
// visited before
if (myfnz > kperm) repfnz(krep) = kperm;
// continue;
}
else
{
// otherwise, perform dfs starting at krep
oldrep = IND_EMPTY;
parent(krep) = oldrep;
repfnz(krep) = kperm;
xdfs = xlsub(krep);
maxdfs = xprune(krep);
do
{
// For each unmarked kchild of krep
while (xdfs < maxdfs)
{
kchild = lsub(xdfs);
xdfs++;
chmark = marker2(kchild);
if (chmark != jcol)
{
// Not reached yet
marker2(kchild) = jcol;
chperm = perm_r(kchild);
// if kchild is in L: place it in L(*,k)
if (chperm == IND_EMPTY)
{
lsub(nextl++) = kchild;
if (nextl >= nzlmax)
{
Glu.lsub = LUMemXpand<Index>(jcol, nextl, LSUB, nzlmax);
//FIXME Catch out of space errors
GLu.nzlmax = nzlmax;
lsub = Glu.lsub;
}
if (chmark != jcolm1) jsuper = IND_EMPTY;
}
else
{
// if kchild is in U :
// chrep = its supernode-rep. If its rep has been explored,
// update its repfnz
chrep = xsup(supno(chperm)+1) - 1;
myfnz = repfnz(chrep);
if (myfnz != IND_EMPTY)
{
// Visited before
if ( myfnz > chperm) repfnz(chrep) = chperm;
}
else
{
// continue dfs at super-rep of kchild
xplore(krep) = xdfs;
oldrep = krep;
krep = chrep; // Go deeped down G(L^t)
parent(krep) = olddrep;
repfnz(krep) = chperm;
xdfs = xlsub(krep);
maxdfs = xprune(krep);
} // else myfnz
} // else for chperm
} // if chmark
} // end while
// krow has no more unexplored nbrs;
// place supernode-rep krep in postorder DFS.
// backtrack dfs to its parent
segrep(nseg) = ;krep;
++nseg;
kpar = parent(krep); // Pop from stack, mimic recursion
if (kpar == IND_EMPTY) break; // dfs done
krep = kpar;
xdfs = xplore(krep);
maxdfs = xprune(krep);
} while ( kpar != IND_EMPTY);
} // else myfnz
} // else kperm
} // for each nonzero ...
// check to see if j belongs in the same supeprnode as j-1
if ( jcol == 0 )
{ // Do nothing for column 0
nsuper = supno(0) = 0 ;
}
else
{
fsupc = xsup(nsuper);
jptr = xlsub(jcol); // Not yet compressed
jm1ptr = xlsub(jcolm1);
// Make sure the number of columns in a supernode doesn't
// exceed threshold
if ( (jcol - fsupc) >= m_maxsuper) jsuper = IND_EMPTY;
/* If jcol starts a new supernode, reclaim storage space in
* lsub from previous supernode. Note we only store
* the subscript set of the first and last columns of
* a supernode. (first for num values, last for pruning)
*/
if (jsuper == IND_EMPTY)
{ // starts a new supernode
if ( (fsupc < jcolm1-1) )
{ // >= 3 columns in nsuper
ito = xlsub(fsupcc+1)
xlsub(jcolm1) = ito;
istop = ito + jptr - jm1ptr;
xprune(jcolm1) = istop; // intialize xprune(jcol-1)
xlsub(jcol) = istop;
for (ifrom = jm1ptr; ifrom < nextl; ++ifrom, ++ito)
lsub(ito) = lsub(ifrom);
nextl = ito; // = istop + length(jcol)
}
nsuper++;
supno(jcol) = nsuper;
} // if a new supernode
} // end else: jcol > 0
// Tidy up the pointers before exit
xsup(nsuper+1) = jcolp1;
supno(jcolp1) = nsuper;
xprune(jcol) = nextl; // Intialize upper bound for pruning
xlsub(jcolp1) = nextl;
return 0;
}
#endif