zcopy_to_ucol.c

SuperLU is a general purpose library for the direct solution of large, sparse, nonsymmetric systems

/*! @file zcopy_to_ucol.c
 * \brief Copy a computed column of U to the compressed data structure
 *
 * <pre>
 * -- 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.
 * </pre>
 */

#include "slu_zdefs.h"

int
zcopy_to_ucol(
	      int        jcol,	  /* in */
	      int        nseg,	  /* in */
	      int        *segrep,  /* in */
	      int        *repfnz,  /* in */
	      int        *perm_r,  /* in */
	      doublecomplex     *dense,   /* modified - reset to zero on return */
	      GlobalLU_t *Glu      /* modified */
	      )
{
/* 
 * Gather from SPA dense[*] to global ucol[*].
 */
    int ksub, krep, ksupno;
    int i, k, kfnz, segsze;
    int fsupc, isub, irow;
    int jsupno, nextu;
    int new_next, mem_error;
    int       *xsup, *supno;
    int       *lsub, *xlsub;
    doublecomplex    *ucol;
    int       *usub, *xusub;
    int       nzumax;

    doublecomplex zero = {0.0, 0.0};

    xsup    = Glu->xsup;
    supno   = Glu->supno;
    lsub    = Glu->lsub;
    xlsub   = Glu->xlsub;
    ucol    = Glu->ucol;
    usub    = Glu->usub;
    xusub   = Glu->xusub;
    nzumax  = Glu->nzumax;
    
    jsupno = supno[jcol];
    nextu  = xusub[jcol];
    k = nseg - 1;
    for (ksub = 0; ksub < nseg; ksub++) {
	krep = segrep[k--];
	ksupno = supno[krep];

	if ( ksupno != jsupno ) { /* Should go into ucol[] */
	    kfnz = repfnz[krep];
	    if ( kfnz != EMPTY ) {	/* Nonzero U-segment */

	    	fsupc = xsup[ksupno];
	        isub = xlsub[fsupc] + kfnz - fsupc;
	        segsze = krep - kfnz + 1;

		new_next = nextu + segsze;
		while ( new_next > nzumax ) {
		    if (mem_error = zLUMemXpand(jcol, nextu, UCOL, &nzumax, Glu))
			return (mem_error);
		    ucol = Glu->ucol;
		    if (mem_error = zLUMemXpand(jcol, nextu, USUB, &nzumax, Glu))
			return (mem_error);
		    usub = Glu->usub;
		    lsub = Glu->lsub;
		}
		
		for (i = 0; i < segsze; i++) {
		    irow = lsub[isub];
		    usub[nextu] = perm_r[irow];
		    ucol[nextu] = dense[irow];
		    dense[irow] = zero;
		    nextu++;
		    isub++;
		} 

	    }

	}

    } /* for each segment... */

    xusub[jcol + 1] = nextu;      /* Close U[*,jcol] */
    return 0;
}