/* nag_1d_quad_inf_1 (d01smc) Example Program.
 *
 * Copyright 1998 Numerical Algorithms Group.
 *
 * Mark 5, 1998.
 * Mark 6 revised, 2000.
 * Mark 7 revised, 2001.
 *
 */

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

#ifdef __cplusplus
extern "C" {
#endif
  static double f(double x, Nag_User *comm);
#ifdef __cplusplus
}
#endif

int main(void)
{

  double a;
  double epsabs, abserr, epsrel, result;
  Nag_QuadProgress qp;
  Integer max_num_subint;
  static NagError fail;
  Nag_User comm;

  Vprintf("nag_1d_quad_inf_1 (d01smc) Example Program Results\n");
  epsabs = 0.0;
  epsrel = 0.0001;
  a = 0.0;
  max_num_subint = 200;

  /* nag_1d_quad_inf_1 (d01smc).
   * One-dimensional adaptive quadrature over infinite or
   * semi-infinite interval, thread-safe
   */
  nag_1d_quad_inf_1(f, Nag_UpperSemiInfinite,  a, epsabs, epsrel,
                    max_num_subint, &result, &abserr, &qp, &comm, &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", epsabs);
  Vprintf("epsrel - relative accuracy requested = %9.2e\n\n", epsrel);
  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 && fail.code != NE_NO_LICENCE)
    {
      Vprintf("result - approximation to the integral = %9.5f\n", result);
      Vprintf("abserr - estimate of the absolute error = %9.2e\n", abserr);
      Vprintf("qp.fun_count  - number of function evaluations = %4ld\n",
              qp.fun_count);
      Vprintf("qp.num_subint  - number of subintervals used = %4ld\n",
              qp.num_subint);
      /* Free memory used by qp */
      NAG_FREE(qp.sub_int_beg_pts);
      NAG_FREE(qp.sub_int_end_pts);
      NAG_FREE(qp.sub_int_result);
      NAG_FREE(qp.sub_int_error);
      return EXIT_SUCCESS;
    }
  return EXIT_FAILURE;
}
static double f(double x, Nag_User *comm)
{
  return 1.0/((x+1.0)*sqrt(x));
}