/* ========================================================================== */
  /* === 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"
  ", k, i)) ;
  	if (i < 0 || i >= n)
  	{
  	    DEBUG0 (("i out of range "ID" "ID"
  ", i, n)) ;
  	    return (FALSE) ;
  	}
  	if (W [i])
  	{
  	    DEBUG0 (("i duplicate "ID"
  ", i)) ;
  	    return (FALSE) ;
  	}
  	W [i] = TRUE ;
      }
      return (TRUE) ;
  }