HermitePolynomialsTest.h

#ifndef MANTID_KERNEL_HERMITEPOLYNOMIALSTEST_H_
#define MANTID_KERNEL_HERMITEPOLYNOMIALSTEST_H_

#include <cxxtest/TestSuite.h>
#include <iomanip>
#include "MantidKernel/Math/Distributions/HermitePolynomials.h"

class HermitePolynomialsTest : public CxxTest::TestSuite {
public:
  // This pair of boilerplate methods prevent the suite being created statically
  // This means the constructor isn't called when running other tests
  static HermitePolynomialsTest *createSuite() {
    return new HermitePolynomialsTest();
  }
  static void destroySuite(HermitePolynomialsTest *suite) { delete suite; }

  void
  test_hermitePoly_With_SingleValue_Returns_Expected_Values_For_First_Few_Terms() {
    using namespace Mantid::Kernel;
    static const unsigned int npoly(6);

    const double xValue = 3.98753;
    const double expectedValues[npoly] = {1, 7.97506, 61.6015820036,
                                          459.376072573630, 3293.942249317455,
                                          22594.378494252622};

    const double tolerance(1e-12);
    for (unsigned int i = 0; i < npoly; ++i) {
      TS_ASSERT_DELTA(expectedValues[i], Math::hermitePoly(i, xValue),
                      tolerance);
    }
  }

  void
  test_hermitePoly_With_Array_Values_Returns_Expected_Values_For_First_Few_Terms() {
    using namespace Mantid::Kernel;

    static const unsigned int nx(5), npoly(3);
    std::vector<double> xvalues(nx, 1.0);
    const double delta = std::sqrt(3.);
    for (size_t i = 1; i < nx; ++i) {
      xvalues[i] = xvalues[i - 1] + delta;
    }

    const double expectedValues[npoly][nx] = {
        {1, 1, 1, 1, 1},
        {2, 5.464101615138, 8.928203230276, 12.392304845413, 15.856406460551},
        {2, 27.856406460551, 77.712812921102, 151.569219381653,
         249.425625842204},
    };
    const double tolerance(1e-12);
    for (unsigned int i = 0; i < npoly; ++i) {
      auto hpoly = Math::hermitePoly(i, xvalues);
      for (unsigned int j = 0; j < nx; ++j) {
        TS_ASSERT_DELTA(expectedValues[i][j], hpoly[j], tolerance);
      }
    }
  }
};

#endif /* MANTID_KERNEL_HERMITEPOLYNOMIALSTEST_H_ */