/* nag_correg_linregs_noconst (g02cbc) Example Program.
 *
 * Copyright 2021 Numerical Algorithms Group.
 *
 * Mark 27.3, 2021.
 */

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

int main(void) {
  Integer exit_status = 0, i, n;
  double clm, clp;
  double *h = 0, *res = 0, rms, *wt = 0, *x = 0, *y = 0, *yhat = 0;
  double *yl = 0, *yml = 0, *ymu = 0, *yu = 0;
  char nag_enum_arg[40];
  Nag_SumSquare mean;
  Nag_Boolean weight;
  NagError fail;

  INIT_FAIL(fail);

  printf("nag_correg_linregs_noconst (g02cbc) Example Program Results\n");
  /* Skip heading in data file */
  scanf("%*[^\n]");
  scanf("%" NAG_IFMT "\n", &n);
  scanf("%lf%lf\n", &clm, &clp);
  scanf(" %39s", nag_enum_arg);
  /* nag_enum_name_to_value (x04nac).
   * Converts NAG enum member name to value
   */
  mean = (Nag_SumSquare)nag_enum_name_to_value(nag_enum_arg);
  scanf(" %39s", nag_enum_arg);
  weight = (Nag_Boolean)nag_enum_name_to_value(nag_enum_arg);
  if (n >= (mean == Nag_AboutMean ? 2 : 1)) {
    if (!(x = NAG_ALLOC(n, double)) || !(y = NAG_ALLOC(n, double)) ||
        !(wt = NAG_ALLOC(n, double)) || !(yhat = NAG_ALLOC(n, double)) ||
        !(yml = NAG_ALLOC(n, double)) || !(ymu = NAG_ALLOC(n, double)) ||
        !(yl = NAG_ALLOC(n, double)) || !(yu = NAG_ALLOC(n, double)) ||
        !(h = NAG_ALLOC(n, double)) || !(res = NAG_ALLOC(n, double))) {
      printf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }
  } else {
    printf("Invalid n.\n");
    exit_status = 1;
    return exit_status;
  }
  if (weight)
    for (i = 0; i < n; i++)
      scanf("%lf%lf%lf\n", &x[i], &y[i], &wt[i]);
  else
    for (i = 0; i < n; ++i)
      scanf("%lf%lf\n", &x[i], &y[i]);

  /* nag_correg_linregs_noconst (g02cbc).
   * Simple linear regression confidence intervals for the
   * regression line and individual points
   */
  nag_correg_linregs_noconst(mean, n, x, y, wt, clm, clp, yhat, yml, ymu, yl,
                             yu, h, res, &rms, &fail);
  if (fail.code != NE_NOERROR) {
    printf("Error from nag_correg_linregs_noconst (g02cbc).\n%s\n",
           fail.message);
    exit_status = 1;
    goto END;
  }

  printf("\ni       yhat[i]    yml[i]    ymu[i]      yl[i]      yu[i]"
         " \n\n");
  for (i = 0; i < n; ++i) {
    printf("%" NAG_IFMT " %10.2f %10.2f", i, yhat[i], yml[i]);
    printf("%10.2f  %10.2f %10.2f\n", ymu[i], yl[i], yu[i]);
  }

END:
  NAG_FREE(x);
  NAG_FREE(y);
  NAG_FREE(wt);
  NAG_FREE(yhat);
  NAG_FREE(yml);
  NAG_FREE(ymu);
  NAG_FREE(yl);
  NAG_FREE(yu);
  NAG_FREE(h);
  NAG_FREE(res);

  return exit_status;
}