/*
 * 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"
/* remove duplicate entries from A */
CS_INT cs_dupl (cs *A)
{
    CS_INT i, j, p, q, nz = 0, n, m, *Ap, *Ai, *w ;
    CS_ENTRY *Ax ;
    if (!CS_CSC (A)) return (0) ;               /* check inputs */
    m = A->m ; n = A->n ; Ap = A->p ; Ai = A->i ; Ax = A->x ;
    w = cs_malloc (m, sizeof (CS_INT)) ;           /* get workspace */
    if (!w) return (0) ;                        /* out of memory */
    for (i = 0 ; i < m ; i++) w [i] = -1 ;      /* row i not yet seen */
    for (j = 0 ; j < n ; j++)
    {
        q = nz ;                                /* column j will start at q */
        for (p = Ap [j] ; p < Ap [j+1] ; p++)
        {
            i = Ai [p] ;                        /* A(i,j) is nonzero */
            if (w [i] >= q)
            {
                Ax [w [i]] += Ax [p] ;          /* A(i,j) is a duplicate */
            }
            else
            {
                w [i] = nz ;                    /* record where row i occurs */
                Ai [nz] = i ;                   /* keep A(i,j) */
                Ax [nz++] = Ax [p] ;
            }
        }
        Ap [j] = q ;                            /* record start of column j */
    }
    Ap [n] = nz ;                               /* finalize A */
    cs_free (w) ;                               /* free workspace */
    return (cs_sprealloc (A, 0)) ;              /* remove extra space from A */
}