/*
 * 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"
/* pinv = p', or p = pinv' */
CS_INT *cs_pinv (CS_INT const *p, CS_INT n)
{
    CS_INT k, *pinv ;
    if (!p) return (NULL) ;                     /* p = NULL denotes identity */
    pinv = cs_malloc (n, sizeof (CS_INT)) ;        /* allocate result */
    if (!pinv) return (NULL) ;                  /* out of memory */
    for (k = 0 ; k < n ; k++) pinv [p [k]] = k ;/* invert the permutation */
    return (pinv) ;                             /* return result */
}