/* nag_rand_permute (g05ncc) Example Program.
 *
 * Copyright 2024 Numerical Algorithms Group.
 *
 * Mark 30.0, 2024.
 */
/* Pre-processor includes */
#include <math.h>
#include <nag.h>
#include <stdio.h>

int main(void) {
  /* Integer scalar and array declarations */
  Integer exit_status = 0;
  Integer i, j, lstate;
  Integer *index = 0, *state = 0;

  /* NAG structures */
  NagError fail;

  /* Number of permutations */
  Integer m = 10;

  /* Sample size */
  Integer n = 8;

  /* Choose the base generator */
  Nag_BaseRNG genid = Nag_Basic;
  Integer subid = 0;

  /* Set the seed */
  Integer seed[] = {1762543};
  Integer lseed = 1;

  /* Initialize the error structure */
  INIT_FAIL(fail);

  printf("nag_rand_permute (g05ncc) Example Program Results\n\n");

  /* Get the length of the state array */
  lstate = -1;
  nag_rand_init_repeat(genid, subid, seed, lseed, state, &lstate, &fail);
  if (fail.code != NE_NOERROR) {
    printf("Error from nag_rand_init_repeat (g05kfc).\n%s\n", fail.message);
    exit_status = 1;
    goto END;
  }

  /* Allocate arrays */
  if (!(index = NAG_ALLOC(n, Integer)) ||
      !(state = NAG_ALLOC(lstate, Integer))) {
    printf("Allocation failure\n");
    exit_status = -1;
    goto END;
  }

  /* Initialize the generator to a repeatable sequence */
  nag_rand_init_repeat(genid, subid, seed, lseed, state, &lstate, &fail);
  if (fail.code != NE_NOERROR) {
    printf("Error from nag_rand_init_repeat (g05kfc).\n%s\n", fail.message);
    exit_status = 1;
    goto END;
  }

  printf(" %2" NAG_IFMT " Permutations of first %1" NAG_IFMT " integers\n", m,
         n);

  /* Permutate M times */
  for (j = 0; j < m; j++) {
    /* Set up the index vector */
    for (i = 0; i < n; i++)
      index[i] = i + 1;

    /* Call the permutation routine */
    nag_rand_permute(index, n, state, &fail);
    if (fail.code != NE_NOERROR) {
      printf("Error from nag_rand_permute (g05ncc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }

    /* Display the results */
    printf("  ");
    for (i = 0; i < n; i++)
      printf("%2" NAG_IFMT "%s", index[i], (i + 1) % 8 ? " " : "\n");
    if (n % 8)
      printf("\n");
  }

END:
  NAG_FREE(index);
  NAG_FREE(state);

  return exit_status;
}