/*! \file
Copyright (c) 2003, The Regents of the University of California, through
Lawrence Berkeley National Laboratory (subject to receipt of any required 
approvals from U.S. Dept. of Energy) 

All rights reserved. 

The source code is distributed under BSD license, see the file License.txt
at the top-level directory.
*/

/*! @file cpanel_bmod.c
 * \brief Performs numeric block updates
 *
 * <pre>
 * -- SuperLU routine (version 3.0) --
 * Univ. of California Berkeley, Xerox Palo Alto Research Center,
 * and Lawrence Berkeley National Lab.
 * October 15, 2003
 *
 * 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 <stdio.h>
#include <stdlib.h>
#include "slu_cdefs.h"

/*! \brief
 *
 * <pre>
 * Purpose
 * =======
 *
 *    Performs numeric block updates (sup-panel) in topological order.
 *    It features: col-col, 2cols-col, 3cols-col, and sup-col updates.
 *    Special processing on the supernodal portion of L\U[*,j]
 *
 *    Before entering this routine, the original nonzeros in the panel 
 *    were already copied into the spa[m,w].
 *
 *    Updated/Output parameters-
 *    dense[0:m-1,w]: L[*,j:j+w-1] and U[*,j:j+w-1] are returned 
 *    collectively in the m-by-w vector dense[*]. 
 * </pre>
 */

void
cpanel_bmod (
	    const int  m,          /* in - number of rows in the matrix */
	    const int  w,          /* in */
	    const int  jcol,       /* in */
	    const int  nseg,       /* in */
	    complex     *dense,     /* out, of size n by w */
	    complex     *tempv,     /* working array */
	    int        *segrep,    /* in */
	    int        *repfnz,    /* in, of size n by w */
	    GlobalLU_t *Glu,       /* modified */
	    SuperLUStat_t *stat    /* output */
	    )
{


#ifdef USE_VENDOR_BLAS
#ifdef _CRAY
    _fcd ftcs1 = _cptofcd("L", strlen("L")),
         ftcs2 = _cptofcd("N", strlen("N")),
         ftcs3 = _cptofcd("U", strlen("U"));
#endif
    int          incx = 1, incy = 1;
    complex       alpha, beta;
#endif

    register int k, ksub;
    int          fsupc, nsupc, nsupr, nrow;
    int          krep, krep_ind;
    complex       ukj, ukj1, ukj2;
    int          luptr, luptr1, luptr2;
    int          segsze;
    int          block_nrow;  /* no of rows in a block row */
    register int lptr;	      /* Points to the row subscripts of a supernode */
    int          kfnz, irow, no_zeros; 
    register int isub, isub1, i;
    register int jj;	      /* Index through each column in the panel */
    int          *xsup, *supno;
    int          *lsub, *xlsub;
    complex       *lusup;
    int          *xlusup;
    int          *repfnz_col; /* repfnz[] for a column in the panel */
    complex       *dense_col;  /* dense[] for a column in the panel */
    complex       *tempv1;             /* Used in 1-D update */
    complex       *TriTmp, *MatvecTmp; /* used in 2-D update */
    complex      zero = {0.0, 0.0};
    complex      one = {1.0, 0.0};
    complex      comp_temp, comp_temp1;
    register int ldaTmp;
    register int r_ind, r_hi;
    int  maxsuper, rowblk, colblk;
    flops_t  *ops = stat->ops;
    
    xsup    = Glu->xsup;
    supno   = Glu->supno;
    lsub    = Glu->lsub;
    xlsub   = Glu->xlsub;
    lusup   = (complex *) Glu->lusup;
    xlusup  = Glu->xlusup;
    
    maxsuper = SUPERLU_MAX( sp_ienv(3), sp_ienv(7) );
    rowblk   = sp_ienv(4);
    colblk   = sp_ienv(5);
    ldaTmp   = maxsuper + rowblk;

    /* 
     * For each nonz supernode segment of U[*,j] in topological order 
     */
    k = nseg - 1;
    for (ksub = 0; ksub < nseg; ksub++) { /* for each updating supernode */

	/* krep = representative of current k-th supernode
	 * fsupc = first supernodal column
	 * nsupc = no of columns in a supernode
	 * nsupr = no of rows in a supernode
	 */
        krep = segrep[k--];
	fsupc = xsup[supno[krep]];
	nsupc = krep - fsupc + 1;
	nsupr = xlsub[fsupc+1] - xlsub[fsupc];
	nrow = nsupr - nsupc;
	lptr = xlsub[fsupc];
	krep_ind = lptr + nsupc - 1;

	repfnz_col = repfnz;
	dense_col = dense;
	
	if ( nsupc >= colblk && nrow > rowblk ) { /* 2-D block update */

	    TriTmp = tempv;
	
	    /* Sequence through each column in panel -- triangular solves */
	    for (jj = jcol; jj < jcol + w; jj++,
		 repfnz_col += m, dense_col += m, TriTmp += ldaTmp ) {

		kfnz = repfnz_col[krep];
		if ( kfnz == EMPTY ) continue;	/* Skip any zero segment */
	    
		segsze = krep - kfnz + 1;
		luptr = xlusup[fsupc];

		ops[TRSV] += 4 * segsze * (segsze - 1);
		ops[GEMV] += 8 * nrow * segsze;
	
		/* Case 1: Update U-segment of size 1 -- col-col update */
		if ( segsze == 1 ) {
		    ukj = dense_col[lsub[krep_ind]];
		    luptr += nsupr*(nsupc-1) + nsupc;

		    for (i = lptr + nsupc; i < xlsub[fsupc+1]; i++) {
			irow = lsub[i];
	    	        cc_mult(&comp_temp, &ukj, &lusup[luptr]);
		        c_sub(&dense_col[irow], &dense_col[irow], &comp_temp);
			++luptr;
		    }

		} else if ( segsze <= 3 ) {
		    ukj = dense_col[lsub[krep_ind]];
		    ukj1 = dense_col[lsub[krep_ind - 1]];
		    luptr += nsupr*(nsupc-1) + nsupc-1;
		    luptr1 = luptr - nsupr;

		    if ( segsze == 2 ) {
		        cc_mult(&comp_temp, &ukj1, &lusup[luptr1]);
		        c_sub(&ukj, &ukj, &comp_temp);
			dense_col[lsub[krep_ind]] = ukj;
			for (i = lptr + nsupc; i < xlsub[fsupc+1]; ++i) {
			    irow = lsub[i];
			    luptr++; luptr1++;
			    cc_mult(&comp_temp, &ukj, &lusup[luptr]);
			    cc_mult(&comp_temp1, &ukj1, &lusup[luptr1]);
			    c_add(&comp_temp, &comp_temp, &comp_temp1);
			    c_sub(&dense_col[irow], &dense_col[irow], &comp_temp);
			}
		    } else {
			ukj2 = dense_col[lsub[krep_ind - 2]];
			luptr2 = luptr1 - nsupr;
  		        cc_mult(&comp_temp, &ukj2, &lusup[luptr2-1]);
		        c_sub(&ukj1, &ukj1, &comp_temp);

		        cc_mult(&comp_temp, &ukj1, &lusup[luptr1]);
        		cc_mult(&comp_temp1, &ukj2, &lusup[luptr2]);
		        c_add(&comp_temp, &comp_temp, &comp_temp1);
		        c_sub(&ukj, &ukj, &comp_temp);
			dense_col[lsub[krep_ind]] = ukj;
			dense_col[lsub[krep_ind-1]] = ukj1;
			for (i = lptr + nsupc; i < xlsub[fsupc+1]; ++i) {
			    irow = lsub[i];
			    luptr++; luptr1++; luptr2++;
			    cc_mult(&comp_temp, &ukj, &lusup[luptr]);
			    cc_mult(&comp_temp1, &ukj1, &lusup[luptr1]);
			    c_add(&comp_temp, &comp_temp, &comp_temp1);
			    cc_mult(&comp_temp1, &ukj2, &lusup[luptr2]);
			    c_add(&comp_temp, &comp_temp, &comp_temp1);
			    c_sub(&dense_col[irow], &dense_col[irow], &comp_temp);
			}
		    }

		} else  {	/* segsze >= 4 */
		    
		    /* Copy U[*,j] segment from dense[*] to TriTmp[*], which
		       holds the result of triangular solves.    */
		    no_zeros = kfnz - fsupc;
		    isub = lptr + no_zeros;
		    for (i = 0; i < segsze; ++i) {
			irow = lsub[isub];
			TriTmp[i] = dense_col[irow]; /* Gather */
			++isub;
		    }
		    
		    /* start effective triangle */
		    luptr += nsupr * no_zeros + no_zeros;

#ifdef USE_VENDOR_BLAS
#ifdef _CRAY
		    CTRSV( ftcs1, ftcs2, ftcs3, &segsze, &lusup[luptr], 
			   &nsupr, TriTmp, &incx );
#else
		    ctrsv_( "L", "N", "U", &segsze, &lusup[luptr], 
			   &nsupr, TriTmp, &incx );
#endif
#else		
		    clsolve ( nsupr, segsze, &lusup[luptr], TriTmp );
#endif
		    

		} /* else ... */
	    
	    }  /* for jj ... end tri-solves */

	    /* Block row updates; push all the way into dense[*] block */
	    for ( r_ind = 0; r_ind < nrow; r_ind += rowblk ) {
		
		r_hi = SUPERLU_MIN(nrow, r_ind + rowblk);
		block_nrow = SUPERLU_MIN(rowblk, r_hi - r_ind);
		luptr = xlusup[fsupc] + nsupc + r_ind;
		isub1 = lptr + nsupc + r_ind;
		
		repfnz_col = repfnz;
		TriTmp = tempv;
		dense_col = dense;
		
		/* Sequence through each column in panel -- matrix-vector */
		for (jj = jcol; jj < jcol + w; jj++,
		     repfnz_col += m, dense_col += m, TriTmp += ldaTmp) {
		    
		    kfnz = repfnz_col[krep];
		    if ( kfnz == EMPTY ) continue; /* Skip any zero segment */
		    
		    segsze = krep - kfnz + 1;
		    if ( segsze <= 3 ) continue;   /* skip unrolled cases */
		    
		    /* Perform a block update, and scatter the result of
		       matrix-vector to dense[].		 */
		    no_zeros = kfnz - fsupc;
		    luptr1 = luptr + nsupr * no_zeros;
		    MatvecTmp = &TriTmp[maxsuper];
		    
#ifdef USE_VENDOR_BLAS
		    alpha = one; 
                    beta = zero;
#ifdef _CRAY
		    CGEMV(ftcs2, &block_nrow, &segsze, &alpha, &lusup[luptr1], 
			   &nsupr, TriTmp, &incx, &beta, MatvecTmp, &incy);
#else
		    cgemv_("N", &block_nrow, &segsze, &alpha, &lusup[luptr1], 
			   &nsupr, TriTmp, &incx, &beta, MatvecTmp, &incy);
#endif
#else
		    cmatvec(nsupr, block_nrow, segsze, &lusup[luptr1],
			   TriTmp, MatvecTmp);
#endif
		    
		    /* Scatter MatvecTmp[*] into SPA dense[*] temporarily
		     * such that MatvecTmp[*] can be re-used for the
		     * the next blok row update. dense[] will be copied into 
		     * global store after the whole panel has been finished.
		     */
		    isub = isub1;
		    for (i = 0; i < block_nrow; i++) {
			irow = lsub[isub];
		        c_sub(&dense_col[irow], &dense_col[irow], 
                              &MatvecTmp[i]);
			MatvecTmp[i] = zero;
			++isub;
		    }
		    
		} /* for jj ... */
		
	    } /* for each block row ... */
	    
	    /* Scatter the triangular solves into SPA dense[*] */
	    repfnz_col = repfnz;
	    TriTmp = tempv;
	    dense_col = dense;
	    
	    for (jj = jcol; jj < jcol + w; jj++,
		 repfnz_col += m, dense_col += m, TriTmp += ldaTmp) {
		kfnz = repfnz_col[krep];
		if ( kfnz == EMPTY ) continue; /* Skip any zero segment */
		
		segsze = krep - kfnz + 1;
		if ( segsze <= 3 ) continue; /* skip unrolled cases */
		
		no_zeros = kfnz - fsupc;		
		isub = lptr + no_zeros;
		for (i = 0; i < segsze; i++) {
		    irow = lsub[isub];
		    dense_col[irow] = TriTmp[i];
		    TriTmp[i] = zero;
		    ++isub;
		}
		
	    } /* for jj ... */
	    
	} else { /* 1-D block modification */
	    
	    
	    /* Sequence through each column in the panel */
	    for (jj = jcol; jj < jcol + w; jj++,
		 repfnz_col += m, dense_col += m) {
		
		kfnz = repfnz_col[krep];
		if ( kfnz == EMPTY ) continue;	/* Skip any zero segment */
		
		segsze = krep - kfnz + 1;
		luptr = xlusup[fsupc];

		ops[TRSV] += 4 * segsze * (segsze - 1);
		ops[GEMV] += 8 * nrow * segsze;
		
		/* Case 1: Update U-segment of size 1 -- col-col update */
		if ( segsze == 1 ) {
		    ukj = dense_col[lsub[krep_ind]];
		    luptr += nsupr*(nsupc-1) + nsupc;

		    for (i = lptr + nsupc; i < xlsub[fsupc+1]; i++) {
			irow = lsub[i];
	    	        cc_mult(&comp_temp, &ukj, &lusup[luptr]);
		        c_sub(&dense_col[irow], &dense_col[irow], &comp_temp);
			++luptr;
		    }

		} else if ( segsze <= 3 ) {
		    ukj = dense_col[lsub[krep_ind]];
		    luptr += nsupr*(nsupc-1) + nsupc-1;
		    ukj1 = dense_col[lsub[krep_ind - 1]];
		    luptr1 = luptr - nsupr;

		    if ( segsze == 2 ) {
		        cc_mult(&comp_temp, &ukj1, &lusup[luptr1]);
		        c_sub(&ukj, &ukj, &comp_temp);
			dense_col[lsub[krep_ind]] = ukj;
			for (i = lptr + nsupc; i < xlsub[fsupc+1]; ++i) {
			    irow = lsub[i];
			    ++luptr;  ++luptr1;
			    cc_mult(&comp_temp, &ukj, &lusup[luptr]);
			    cc_mult(&comp_temp1, &ukj1, &lusup[luptr1]);
			    c_add(&comp_temp, &comp_temp, &comp_temp1);
			    c_sub(&dense_col[irow], &dense_col[irow], &comp_temp);
			}
		    } else {
			ukj2 = dense_col[lsub[krep_ind - 2]];
			luptr2 = luptr1 - nsupr;
  		        cc_mult(&comp_temp, &ukj2, &lusup[luptr2-1]);
		        c_sub(&ukj1, &ukj1, &comp_temp);

		        cc_mult(&comp_temp, &ukj1, &lusup[luptr1]);
        		cc_mult(&comp_temp1, &ukj2, &lusup[luptr2]);
		        c_add(&comp_temp, &comp_temp, &comp_temp1);
		        c_sub(&ukj, &ukj, &comp_temp);
			dense_col[lsub[krep_ind]] = ukj;
			dense_col[lsub[krep_ind-1]] = ukj1;
			for (i = lptr + nsupc; i < xlsub[fsupc+1]; ++i) {
			    irow = lsub[i];
			    ++luptr; ++luptr1; ++luptr2;
			    cc_mult(&comp_temp, &ukj, &lusup[luptr]);
			    cc_mult(&comp_temp1, &ukj1, &lusup[luptr1]);
			    c_add(&comp_temp, &comp_temp, &comp_temp1);
			    cc_mult(&comp_temp1, &ukj2, &lusup[luptr2]);
			    c_add(&comp_temp, &comp_temp, &comp_temp1);
			    c_sub(&dense_col[irow], &dense_col[irow], &comp_temp);
			}
		    }

		} else  { /* segsze >= 4 */
		    /* 
		     * Perform a triangular solve and block update,
		     * then scatter the result of sup-col update to dense[].
		     */
		    no_zeros = kfnz - fsupc;
		    
		    /* Copy U[*,j] segment from dense[*] to tempv[*]: 
		     *    The result of triangular solve is in tempv[*];
		     *    The result of matrix vector update is in dense_col[*]
		     */
		    isub = lptr + no_zeros;
		    for (i = 0; i < segsze; ++i) {
			irow = lsub[isub];
			tempv[i] = dense_col[irow]; /* Gather */
			++isub;
		    }
		    
		    /* start effective triangle */
		    luptr += nsupr * no_zeros + no_zeros;
		    
#ifdef USE_VENDOR_BLAS
#ifdef _CRAY
		    CTRSV( ftcs1, ftcs2, ftcs3, &segsze, &lusup[luptr], 
			   &nsupr, tempv, &incx );
#else
		    ctrsv_( "L", "N", "U", &segsze, &lusup[luptr], 
			   &nsupr, tempv, &incx );
#endif
		    
		    luptr += segsze;	/* Dense matrix-vector */
		    tempv1 = &tempv[segsze];
                    alpha = one;
                    beta = zero;
#ifdef _CRAY
		    CGEMV( ftcs2, &nrow, &segsze, &alpha, &lusup[luptr], 
			   &nsupr, tempv, &incx, &beta, tempv1, &incy );
#else
		    cgemv_( "N", &nrow, &segsze, &alpha, &lusup[luptr], 
			   &nsupr, tempv, &incx, &beta, tempv1, &incy );
#endif
#else
		    clsolve ( nsupr, segsze, &lusup[luptr], tempv );
		    
		    luptr += segsze;        /* Dense matrix-vector */
		    tempv1 = &tempv[segsze];
		    cmatvec (nsupr, nrow, segsze, &lusup[luptr], tempv, tempv1);
#endif
		    
		    /* Scatter tempv[*] into SPA dense[*] temporarily, such
		     * that tempv[*] can be used for the triangular solve of
		     * the next column of the panel. They will be copied into 
		     * ucol[*] after the whole panel has been finished.
		     */
		    isub = lptr + no_zeros;
		    for (i = 0; i < segsze; i++) {
			irow = lsub[isub];
			dense_col[irow] = tempv[i];
			tempv[i] = zero;
			isub++;
		    }
		    
		    /* Scatter the update from tempv1[*] into SPA dense[*] */
		    /* Start dense rectangular L */
		    for (i = 0; i < nrow; i++) {
			irow = lsub[isub];
		        c_sub(&dense_col[irow], &dense_col[irow], &tempv1[i]);
			tempv1[i] = zero;
			++isub;	
		    }
		    
		} /* else segsze>=4 ... */
		
	    } /* for each column in the panel... */
	    
	} /* else 1-D update ... */

    } /* for each updating supernode ... */

}



