/* nag_make_indices (m01zac) Example Program.
 *
 * Copyright 1990 Numerical Algorithms Group.
 *
 * Mark 2 revised, 1992.
 * Mark 5 revised, 1998.
 * Mark 7 revised, 2001.
 * Mark 8 revised, 2004.
 *
 */

#include <nag.h>
#include <nagx04.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)
{
  double x = *((const double *) a);
  double y = *((const double *) b);
  return(x < y?-1:(x == y?0:1));
}
#ifdef __cplusplus
}
#endif

#define VEC(I, J) vec[(I) *tdvec + J]
int main(int argc, char *argv[])
{
  FILE     *fpin, *fpout;
  Integer  exit_status = 0, tdvec;
  NagError fail;
  double   *vec = 0;
  size_t   i, j, m, n, *rank = 0;

  INIT_FAIL(fail);

  /* Check for command-line IO options */
  fpin = nag_example_file_io(argc, argv, "-data", NULL);
  fpout = nag_example_file_io(argc, argv, "-results", NULL);
  /* Skip heading in data file */
  fscanf(fpin, "%*[^\n]");
  fprintf(fpout, "nag_make_indices (m01zac) Example Program Results\n");
  fscanf(fpin, "%" NAG_UFMT "%" NAG_UFMT "", &m, &n);
  if (m >= 1 && n >= 1 && n <= n)
    {
      if (!(vec = NAG_ALLOC(m*n, double)) ||
          !(rank = NAG_ALLOC(m, size_t)))
        {
          fprintf(fpout, "Allocation failure\n");
          exit_status = -1;
          goto END;
        }
      tdvec = n;
    }
  else
    {
      fprintf(fpout, "Invalid m or n.\n");
      exit_status = 1;
      return exit_status;
    }
  for (i = 0; i < m; ++i)
    for (j = 0; j < n; ++j)
      fscanf(fpin, "%lf", &VEC(i, j));
  /* nag_rank_sort (m01dsc).
   * Rank sort of set of values of arbitrary data type
   */
  nag_rank_sort((Pointer) vec, m, (ptrdiff_t)(n*sizeof(double)), compare,
                Nag_Ascending, rank, &fail);
  if (fail.code != NE_NOERROR)
    {
      fprintf(fpout, "Error from nag_rank_sort (m01dsc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
  /* nag_make_indices (m01zac).
   * Inverts a permutation converting a rank vector to an
   * index vector or vice versa
   */
  nag_make_indices(rank, m, &fail);
  if (fail.code != NE_NOERROR)
    {
      fprintf(fpout, "Error from nag_make_indices (m01zac).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }
  fprintf(fpout, "Matrix with rows sorted according to column 1\n");
  for (i = 0; i < m; ++i)
    {
      for (j = 0; j < n; ++j)
        fprintf(fpout, " %7.1f ", VEC(rank[i], j));
      fprintf(fpout, "\n");
    }
 END:
  if (fpin != stdin) fclose(fpin);
  if (fpout != stdout) fclose(fpout);
  if (vec) NAG_FREE(vec);
  if (rank) NAG_FREE(rank);
  return exit_status;
}