/**
 *
 * g++ main.cpp -o main.x -L`gsl-config --libs`
 *
 */

#include <math.h>
#include <stdio.h>
#include <stdlib.h>

#include <gsl/gsl_math.h>
#include <gsl/gsl_integration.h>

double f(double x, void * params) {
  return exp(-x*x);
}

int main (void)
{
  size_t const n = 100;
  double const a = 19.3;
  double const b = 20.0;
  double const epsabs = 1.0e-13;
  double const epsrel = 1.0e-13;
  double result = 0.0;
  double abserr = 0.0;
  size_t nevals = 0;

  gsl_integration_cquad_workspace * workspace;
  gsl_function F;

  F.function = &f;
  F.params = NULL;

  workspace = gsl_integration_cquad_workspace_alloc(n);

  gsl_integration_cquad(&F, a, b, epsabs, epsrel, workspace, &result, &abserr, &nevals);

  fprintf(stderr, "result = %.12e\n", result);
  fprintf(stderr, "abserr = %.12e\n", abserr);
  fprintf(stderr, "nevals = %zu\n", nevals);

  gsl_integration_cquad_workspace_free(workspace);

  return 0;
}