/* nag_quad_md_numth_vec (d01gdc) Example Program.
 *
 * Copyright 2011, Numerical Algorithms Group.
 *
 * Mark 23, 2011.
 */

#include <stdio.h>
#include <math.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <nagd01.h>
#include <nagx04.h>

#ifdef __cplusplus
extern "C" {
#endif
  static void NAG_CALL vecfun(Integer ndim, const double x[], double fv[],
                              Integer m, Nag_Comm *comm);
  static void NAG_CALL vecreg(Integer ndim, const double x[], Integer j,
                              double c[], double d[], Integer m,
                              Nag_Comm *comm);
#ifdef __cplusplus
}
#endif

int main(void)
{
  Integer     exit_status = 0;
  Integer     ndim;
  Integer     npts, nrand;
  double      err, res;
  double     *vk = 0;
  Nag_Boolean transform;
  char        nag_enum_arg[40];
  NagError    fail;

  INIT_FAIL(fail);

  printf("nag_quad_md_numth_vec (d01gdc) Example Program Results\n");
  /* Skip heading in data file */
  scanf("%*[^\n] ");
  /* Input parameters */
  scanf("%ld %ld %ld", &ndim, &npts, &nrand);
  scanf("%s %*[^\n] ", nag_enum_arg);   /* Nag_Boolean */
  transform = (Nag_Boolean) nag_enum_name_to_value (nag_enum_arg);

  if (!(vk = NAG_ALLOC(ndim, double)))
    {
      printf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }

  /* nag_quad_md_numth_vec (d01gdc).
   * Multidimensional quadrature, general product region,
   * number-theoretic method.
   */
  nag_quad_md_numth_vec(ndim, vecfun, vecreg, npts, vk, nrand, transform, &res,
                        &err, NAGCOMM_NULL, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_quad_md_numth_vec (d01gdc).\n%s\n",
             fail.message);
      exit_status = 1;
      goto END;
    }

  printf("\nResult = %13.5f, standard error = %10.2e\n", res, err);

 END:
  if (vk) NAG_FREE(vk);

  return exit_status;
}

static void NAG_CALL vecfun(Integer ndim, const double x[], double fv[],
                            Integer m, Nag_Comm *comm)
{
  Integer i, index, j;
  double sum;

  for (i = 0; i < m; i++)
    {
      sum = 0.0;
      for (j = 0, index = 0; j < ndim; j++, index += m) sum += x[i + index];
      fv[i] = cos(0.5 + 2.0 * sum - 4.0);
    }
}

static void NAG_CALL vecreg(Integer ndim, const double x[], Integer j,
                            double c[], double d[], Integer m, Nag_Comm *comm)
{
  Integer i;

  for (i = 0; i < m; i++)
    {
      c[i] = 0.0;
      d[i] = 1.0;
    }
}