ChebyshevPolynomial.cpp

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// Mantid Repository : https://github.com/mantidproject/mantid
//
// Copyright © 2018 ISIS Rutherford Appleton Laboratory UKRI,
//   NScD Oak Ridge National Laboratory, European Spallation Source,
//   Institut Laue - Langevin & CSNS, Institute of High Energy Physics, CAS
// SPDX - License - Identifier: GPL - 3.0 +
//-----------------------------------------------------------------------------
// Includes
//-----------------------------------------------------------------------------
#include "MantidKernel/Math/Distributions/ChebyshevPolynomial.h"
 
#include <cassert>
#include <cmath>
 
using std::acos;
using std::cos;
 
namespace Mantid::Kernel {
 
//-----------------------------------------------------------------------------
// Public members
//-----------------------------------------------------------------------------
double ChebyshevPolynomial::operator()(const size_t n, const double x) {
  assert(x >= -1.0 && x <= 1.0);
  return cos(static_cast<double>(n) * acos(x));
}
 
} // namespace Mantid::Kernel