umf_is_permutation.c
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/* ========================================================================== */
/* === UMF_is_permutation =================================================== */
/* ========================================================================== */
/* -------------------------------------------------------------------------- */
/* UMFPACK Copyright (c) Timothy A. Davis, CISE, */
/* Univ. of Florida. All Rights Reserved. See ../Doc/License for License. */
/* web: http://www.cise.ufl.edu/research/sparse/umfpack */
/* -------------------------------------------------------------------------- */
/* Return TRUE if P is a r-permutation vector, FALSE otherwise */
/* P [0..r-1] must be an r-permutation of 0..n-1 */
#include "umf_internal.h"
GLOBAL Int UMF_is_permutation
(
const Int P [ ], /* permutation of size r */
Int W [ ], /* workspace of size n */
Int n,
Int r
)
{
Int i, k ;
if (!P)
{
/* if P is (Int *) NULL, this is the identity permutation */
return (TRUE) ;
}
ASSERT (W != (Int *) NULL) ;
for (i = 0 ; i < n ; i++)
{
W [i] = FALSE ;
}
for (k = 0 ; k < r ; k++)
{
i = P [k] ;
DEBUG5 (("k "ID" i "ID"\n", k, i)) ;
if (i < 0 || i >= n)
{
DEBUG0 (("i out of range "ID" "ID"\n", i, n)) ;
return (FALSE) ;
}
if (W [i])
{
DEBUG0 (("i duplicate "ID"\n", i)) ;
return (FALSE) ;
}
W [i] = TRUE ;
}
return (TRUE) ;
}