#include <TMath.h>
#include <Math/WrappedFunction.h>
#include <Math/IntegratorMultiDim.h>


using namespace ROOT::Math;


inline
double
Ball(const double* x)
{
  const double r = sqrt(x[0] * x[0] + x[1] * x[1] + x[2] * x[2]);

  if (r > 1.0)
    return 0;

  return 1.0;
}


void
testIntegral()
{
  WrappedMultiFunction<> func(Ball, 3);
  const double R = 1;
  double a[3] = {-R, -R, -R};
  double b[3] = {R, R, R};

  cout << "exact : " << 4.0 * TMath::Pi() / 3.0 << endl;

#define Run(x) \
  { IntegratorMultiDim ig(func, IntegrationMultiDim::x, 1e-9, 1e-9) ; cout << #x << " : " << ig.Integral(a, b) << " , error: " << ig.Error() << endl; }

  Run(kDEFAULT);
  Run(kADAPTIVE);
  Run(kVEGAS);
  Run(kMISER);
  Run(kPLAIN);
}