/* nag_1d_quad_inf_wt_trig_1 (d01ssc) Example Program.
 *
 * Copyright 1998 Numerical Algorithms Group.
 *
 * Mark 5, 1998.
 * Mark 6 revised, 2000.
 * Mark 7 revised, 2001.
 *
 */

#include <nag.h>
#include <nagx04.h>
#include <stdio.h>
#include <nag_stdlib.h>
#include <math.h>
#include <nagd01.h>
#include <nagx01.h>

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

int main(int argc, char *argv[])
{
  FILE                *fpout;
  Integer             exit_status = 0;
  double              a;
  double              omega;
  double              epsabs, abserr;
  Nag_TrigTransform   wt_func;
  double              result;
  Nag_QuadSubProgress qpsub;
  Integer             maxintervals, maxsubint_per_int;
  NagError            fail;
  Nag_User            comm;

  INIT_FAIL(fail);

  /* Check for command-line IO options */
  fpout = nag_example_file_io(argc, argv, "-results", NULL);
  fprintf(fpout,
          "nag_1d_quad_inf_wt_trig_1 (d01ssc) Example Program Results\n");
  epsabs = 0.001;
  a = 0.0;
  /* nag_pi (x01aac).
   * pi
   */
  omega = X01AAC * 0.5;
  wt_func = Nag_Cosine;
  maxintervals = 50;
  maxsubint_per_int = 500;

  /* nag_1d_quad_inf_wt_trig_1 (d01ssc).
   * One-dimensional adaptive quadrature, semi-infinite
   * interval, sine or cosine weight function, thread-safe
   */
  nag_1d_quad_inf_wt_trig_1(g, a, omega, wt_func, maxintervals,
                            maxsubint_per_int, epsabs, &result, &abserr,
                            &qpsub,
                            &comm,
                            &fail);
  fprintf(fpout, "a      - lower limit of integration = %10.4f\n", a);
  fprintf(fpout, "b      - upper limit of integration = infinity\n");
  fprintf(fpout, "epsabs - absolute accuracy requested = %11.2e\n\n", epsabs);
  if (fail.code != NE_NOERROR)
    fprintf(fpout, "Error from nag_1d_quad_inf_wt_trig_1 (d01ssc) %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)
    {
      fprintf(fpout, "result - approximation to the integral = %9.5f\n",
              result);
      fprintf(fpout, "abserr - estimate of the absolute error = %11.2e\n",
              abserr);
      fprintf(fpout, "qpsub.fun_count  - number of function evaluations ="
              " %4ld\n", qpsub.fun_count);
      fprintf(fpout, "qpsub.intervals  - number of intervals used = %4ld\n",
              qpsub.intervals);
      fprintf(fpout, "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);
    }
  else
    {
      exit_status = 1;
      goto END;
    }

 END:
  if (fpout != stdout) fclose(fpout);
  return exit_status;
}


static double NAG_CALL g(double x, Nag_User *comm)
{
  return (x > 0.0)?1.0/sqrt(x):0.0;
}