/* nag_order_data (g10zac) Example Program.
 *
 * Copyright 2000 Numerical Algorithms Group.
 *
 * Mark 6, 2000.
 */

#include <stdio.h>
#include <nag.h>
#include <nagx04.h>
#include <nag_stdlib.h>
#include <nagg10.h>

int main(int argc, char *argv[])
{
  FILE     *fpin, *fpout;
  Integer  exit_status = 0, i, *iwrk = 0, n, nord;
  NagError fail;
  char     weight[2];
  double   rss, *weights = 0, *wtord = 0, *wtptr, *x = 0, *xord = 0, *y = 0;
  double   *yord = 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);
  fprintf(fpout, "nag_order_data (g10zac) Example Program Results\n");

  /* Skip heading in data file */
  fscanf(fpin, "%*[^\n]");

  fscanf(fpin, "%ld", &n);
  if (!(x = NAG_ALLOC(n, double))
     || !(y = NAG_ALLOC(n, double))
     || !(weights = NAG_ALLOC(n, double))
     || !(xord = NAG_ALLOC(n, double))
     || !(yord = NAG_ALLOC(n, double))
     || !(wtord = NAG_ALLOC(n, double))
     || !(iwrk = NAG_ALLOC(n, Integer)))
    {
      fprintf(fpout, "Allocation failure\n");
      exit_status = -1;
      goto END;
    }


  fscanf(fpin, " %s ", weight);
  for (i = 1; i <= n; ++i)
    fscanf(fpin, "%lf %lf", &x[i - 1], &y[i - 1]);
  if (*weight == 'W')
    wtptr = weights;
  else
    wtptr = 0;

  /* nag_order_data (g10zac).
   * Reorder data to give ordered distinct observations
   */
  nag_order_data(n, x, y, wtptr, &nord, xord, yord, wtord, &rss, &fail);
  if (fail.code != NE_NOERROR)
    {
      fprintf(fpout, "Error from nag_order_data (g10zac).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }

  /* Print results */
  fprintf(fpout, "\n");
  fprintf(fpout, "%s%6ld\n", "Number of distinct observations = ",
          nord);
  fprintf(fpout, "%s%13.5f\n", "Residual sum of squares = ", rss);
  fprintf(fpout, "\n");
  fprintf(fpout, "              X                 Y              WEIGHTS\n");
  for (i = 1; i <= nord; ++i)
    fprintf(fpout, "     %13.5f     %13.5f     %13.5f\n", xord[i - 1],
            yord[i - 1], wtord[i - 1]);
 END:
  if (fpin != stdin) fclose(fpin);
  if (fpout != stdout) fclose(fpout);
  if (x) NAG_FREE(x);
  if (y) NAG_FREE(y);
  if (weights) NAG_FREE(weights);
  if (xord) NAG_FREE(xord);
  if (yord) NAG_FREE(yord);
  if (wtord) NAG_FREE(wtord);
  if (iwrk) NAG_FREE(iwrk);
  return exit_status;
}