/* nag_all_regsn (g02eac) Example Program.
 *
 * Copyright 2002 Numerical Algorithms Group.
 *
 * Mark 7, 2002.
 */

#include <math.h>
#include <stdio.h>
#include <string.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <nagg02.h>

int main(void)
{

  /* Scalars */
  Integer exit_status, free_vars, i, ii, j, m, n, nmod, pdx;
  NagError fail;
  Nag_OrderType order;

  /* Arrays */
  char **model=0;
  char *var_names[] = { "DAY", "BOD", "TKN", "TS", "TVS", "COD" };
  double *rss=0, *x=0, *y=0, *wtptr=0;
  Integer *sx=0, *mrank=0, *nterms=0;

  /* For iteration over model */
  Integer model_index=0;

#ifdef NAG_COLUMN_MAJOR
#define X(I,J) x[(J-1)*pdx + I - 1]
  order = Nag_ColMajor;
#else
#define X(I,J) x[(I-1)*pdx + J - 1]
  order = Nag_RowMajor;
#endif

  INIT_FAIL(fail);
  exit_status = 0;
  Vprintf("nag_all_regsn (g02eac) Example Program Results\n");

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

  Vscanf("%ld%ld%*[^\n] ", &n, &m);

  /* Allocate memory */
  if ( !(x = NAG_ALLOC(n * m, double)) ||
       !(y = NAG_ALLOC(n, double)) ||
       !(sx = NAG_ALLOC(m, Integer)) )
    {
      Vprintf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }

#ifdef NAG_COLUMN_MAJOR
  pdx = n;
  order = Nag_ColMajor;
#else
  pdx = m;
  order = Nag_RowMajor;
#endif

  for (i = 1; i <= n; ++i)
    {
      for (j = 1; j <= m; ++j)
        Vscanf("%lf", &X(i,j));
      Vscanf("%lf%*[^\n] ", &y[i - 1]);
    }

  free_vars = 1;
  for (j = 1; j <= m; ++j)
    {
      Vscanf("%ld", &sx[j - 1]);
      if (sx[j - 1] == 1)
        {
          free_vars <<= 1;
        }
    }
  Vscanf("%*[^\n] ");

  if ( !(model = NAG_ALLOC(free_vars*m, char *)) ||
       !(rss = NAG_ALLOC(free_vars, double)) ||
       !(mrank = NAG_ALLOC(free_vars, Integer)) ||
       !(nterms = NAG_ALLOC(free_vars, Integer)) )
    {
      Vprintf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }

  /* nag_all_regsn (g02eac).
   * Computes residual sums of squares for all possible linear
   * regressions for a set of independent variables
   */
  nag_all_regsn(order, Nag_MeanInclude, n, m, x, pdx, var_names, sx, y, wtptr,
                &nmod, model, rss, nterms, mrank, &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from nag_all_regsn (g02eac).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }

  Vprintf("\n");
  Vprintf("Number of     Rss    Rank         Model\n");
  Vprintf("parameters\n");
  for (i = 1; i <= nmod; ++i)
    {
      ii = nterms[i - 1];
      Vprintf("%8ld%11.4f%4ld   ", ii, rss[i-1], mrank[i-1]);
      for (j = 1; j <= ii; ++j)
        Vprintf("%-3.3s %s", model[model_index++],
                j%5 == 0 || j == 5 ?"\n":" ");
      Vprintf("\n");
    }
 END:
  if (rss) NAG_FREE(rss);
  if (x) NAG_FREE(x);
  if (y) NAG_FREE(y);
  if (sx) NAG_FREE(sx);
  if (mrank) NAG_FREE(mrank);
  if (nterms) NAG_FREE(nterms);
  if ( model) NAG_FREE(model);
  return exit_status;
}