/* nag_rngs_permute (g05nac) Example Program.
 *
 * Copyright 2001 Numerical Algorithms Group.
 *
 * Mark 7, 2001.
 */

#include <stdio.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <nagg05.h>

int main(void)
{
  /* Scalars */
  Integer  i, igen, j, k, m, n;
  Integer  exit_status=0;
  NagError fail;

  /* Arrays */
  Integer  *index=0;
  Integer  iseed[4];

  INIT_FAIL(fail);
  Vprintf("nag_rngs_permute (g05nac) Example Program Results\n\n");

  n = 8;
  m = 10;
  /* Allocate memory */
  if ( !(index = NAG_ALLOC(n, Integer)) )
    {
      Vprintf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }

  /* Initialise the seed to a repeatable sequence */
  iseed[0] = 1762543;
  iseed[1] = 9324783;
  iseed[2] = 42344;
  iseed[3] = 742355;
  /* igen identifies the stream. */
  igen = 1;
  /* nag_rngs_init_repeatable (g05kbc).
   * Initialize seeds of a given generator for random number
   * generating functions (that pass seeds explicitly) to give
   * a repeatable sequence
   */
  nag_rngs_init_repeatable(&igen, iseed);
  Vprintf("%2ld Permutations of first %1ld integers\n", m, n);
  Vprintf("\n");

  for (j = 0; j < m; ++j)
    {
      for (i = 0; i < n; ++i)
        index[i] = i + 1;
      /* nag_rngs_permute (g05nac).
       * Pseudo-random permutation of an integer vector
       */
      nag_rngs_permute(index, n, igen, iseed, &fail);
      if (fail.code != NE_NOERROR)
        {
          Vprintf("Error from nag_rngs_permute (g05nac).\n%s\n", fail.message);
          exit_status = 1;
          goto END;
        }
      for (k = 0; k < n; ++k)
        {
          Vprintf("%3ld%s",
                  index[k], (k+1)%8 == 0 || k == n-1 ?"\n":" ");
        }
    }
 END:
  if (index) NAG_FREE(index);
  return exit_status;
}