/* nag_rank_sort (m01dsc) Example Program.
 *
 * Copyright 2017 Numerical Algorithms Group.
 *
 * Mark 26.2, 2017.
 *
 */

#include <nag.h>
#include <stdio.h>
#include <nag_stdlib.h>
#include <nag_stddef.h>
#include <nagm01.h>

#ifdef __cplusplus
extern "C"
{
#endif
  static Integer NAG_CALL compare(const Nag_Pointer a, const Nag_Pointer b);
#ifdef __cplusplus
}
#endif

int main(void)
{
  Integer exit_status = 0;
  NagError fail;
  double *vec = 0;
  ptrdiff_t step;
  size_t i, n, *rank = 0, step_u;

  INIT_FAIL(fail);

  /* Skip heading in data file */
  scanf("%*[^\n]");
  printf("nag_rank_sort (m01dsc) Example Program Results\n\n");
  scanf("%" NAG_UFMT "%" NAG_UFMT "", &n, &step_u);
  step = (ptrdiff_t) step_u;
  if (n >= 1) {
    if (!(vec = NAG_ALLOC(n, double)) || !(rank = NAG_ALLOC(n, size_t))) {
      printf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }
  }
  else {
    printf("Invalid n or step.\n");
    exit_status = 1;
    return exit_status;
  }
  for (i = 0; i < n; ++i)
    scanf("%lf", &vec[i]);
  /* nag_rank_sort (m01dsc).
   * Rank sort of set of values of arbitrary data type
   */
  nag_rank_sort((Pointer) vec, n, step * (ptrdiff_t) (sizeof(double)),
                compare, Nag_Ascending, rank, &fail);
  if (fail.code != NE_NOERROR) {
    printf("Error from nag_rank_sort (m01dsc).\n%s\n", fail.message);
    exit_status = 1;
    goto END;
  }
  printf("    Data      Rank\n");
  for (i = 0; i < n; ++i)
    printf("   %7.4f   %4" NAG_UFMT "\n", vec[i], rank[i]);
END:
  NAG_FREE(vec);
  NAG_FREE(rank);
  return exit_status;
}

static Integer NAG_CALL compare(const Nag_Pointer a, const Nag_Pointer b)
{
  double x = *((const double *) a);
  double y = *((const double *) b);
  return (x < y ? -1 : (x == y ? 0 : 1));
}