/*
* CXSPARSE: a Concise Sparse Matrix package - Extended.
* Copyright (c) 2006-2009, Timothy A. Davis.
* http://www.cise.ufl.edu/research/sparse/CXSparse
*
* CXSparse 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 2.1 of the License, or (at your option) any later version.
*
* CXSparse 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 for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this Module; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "cs.h"
/* C = alpha*A + beta*B */
cs *cs_add (const cs *A, const cs *B, CS_ENTRY alpha, CS_ENTRY beta)
{
CS_INT p, j, nz = 0, anz, *Cp, *Ci, *Bp, m, n, bnz, *w, values ;
CS_ENTRY *x, *Bx, *Cx ;
cs *C ;
if (!CS_CSC (A) || !CS_CSC (B)) return (NULL) ; /* check inputs */
if (A->m != B->m || A->n != B->n) return (NULL) ;
m = A->m ; anz = A->p [A->n] ;
n = B->n ; Bp = B->p ; Bx = B->x ; bnz = Bp [n] ;
w = cs_calloc (m, sizeof (CS_INT)) ; /* get workspace */
values = (A->x != NULL) && (Bx != NULL) ;
x = values ? cs_malloc (m, sizeof (CS_ENTRY)) : NULL ; /* get workspace */
C = cs_spalloc (m, n, anz + bnz, values, 0) ; /* allocate result*/
if (!C || !w || (values && !x)) return (cs_done (C, w, x, 0)) ;
Cp = C->p ; Ci = C->i ; Cx = C->x ;
for (j = 0 ; j < n ; j++)
{
Cp [j] = nz ; /* column j of C starts here */
nz = cs_scatter (A, j, alpha, w, x, j+1, C, nz) ; /* alpha*A(:,j)*/
nz = cs_scatter (B, j, beta, w, x, j+1, C, nz) ; /* beta*B(:,j) */
if (values) for (p = Cp [j] ; p < nz ; p++) Cx [p] = x [Ci [p]] ;
}
Cp [n] = nz ; /* finalize the last column of C */
cs_sprealloc (C, 0) ; /* remove extra space from C */
return (cs_done (C, w, x, 1)) ; /* success; free workspace, return C */
}