/* nag_1d_quad_inf_wt_trig(d01asc) Example Program
 *
 * Copyright 1991 Numerical Algorithms Group.
 *
 * Mark 2, 1991.
 * Mark 6 revised, 2000.
 * Mark 7, revised, 2001.
 *
 */

#include <nag.h>
#include <stdio.h>
#include <nag_stdlib.h>
#include <math.h>
#include <nagd01.h>
#include <nagx01.h>

#ifdef __cplusplus
extern "C" {
#endif
static double g(double x);
#ifdef __cplusplus
}
#endif

int main(void)
{

  double a;
  double omega;
  double epsabs, abserr;
  Nag_TrigTransform wt_func;
  double result;
  Nag_QuadSubProgress qpsub;
  Integer maxintervals, maxsubint_per_int;
  static NagError fail;

  Vprintf("d01asc Example Program Results\n");
  epsabs = 0.001;
  a = 0.0;
  omega = X01AAC * 0.5;
  wt_func = Nag_Cosine;
  maxintervals = 50;
  maxsubint_per_int = 500;
  d01asc(g, a, omega, wt_func, maxintervals, maxsubint_per_int,
         epsabs, &result, &abserr, &qpsub, &fail);
  Vprintf("a      - lower limit of integration = %10.4f\n", a);
  Vprintf("b      - upper limit of integration = infinity\n");
  Vprintf("epsabs - absolute accuracy requested = %9.2e\n\n", epsabs);
  if (fail.code != NE_NOERROR)
    Vprintf("%s\n", fail.message);
  if (fail.code != NE_INT_ARG_LT && fail.code != NE_BAD_PARAM &&
      fail.code != NE_ALLOC_FAIL)
    {
      Vprintf("result - approximation to the integral = %9.5f\n", result);
      Vprintf("abserr - estimate of the absolute error = %9.2e\n", abserr);
      Vprintf("qpsub.fun_count  - number of function evaluations = %4ld\n",
              qpsub.fun_count);
      Vprintf("qpsub.intervals  - number of intervals used = %4ld\n",
              qpsub.intervals);
      Vprintf("qpsub.subints_per_interval  - \n"
              "maximum number of subintervals used in any one interval = %4ld\n",
              qpsub.subints_per_interval);
      /* Free memory used by qpsub */
      NAG_FREE(qpsub.interval_error);
      NAG_FREE(qpsub.interval_result);
      NAG_FREE(qpsub.interval_flag);
      return EXIT_SUCCESS;
    }
  else
    return EXIT_FAILURE;
}


static double g(double x)
{
  return (x > 0.0) ? 1.0/sqrt(x) : 0.0;
}