/*
* 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 */
}