SobolSequence.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/SobolSequence.h"
#include <stdexcept>
 
namespace Mantid::Kernel {
SobolSequence::SobolSequence(const unsigned int ndims)
    : QuasiRandomNumberSequence(ndims), m_gslGenerator(nullptr), m_savedGenerator(nullptr) {
  setNumberOfDimensions(ndims);
}
 
SobolSequence::~SobolSequence() { deleteCurrentGenerator(); }
 
void SobolSequence::generateNextPoint() {
  std::vector<double> &point = getNextPointCache();
  gsl_qrng_get(m_gslGenerator, point.data());
}
 
void SobolSequence::restart() { gsl_qrng_init(m_gslGenerator); }
 
void SobolSequence::save() { m_savedGenerator = gsl_qrng_clone(m_gslGenerator); }
 
void SobolSequence::restore() {
  if (m_savedGenerator) {
    gsl_qrng_memcpy(m_gslGenerator, m_savedGenerator);
  } else {
    restart();
  }
}
 
void SobolSequence::setNumberOfDimensions(const unsigned int ndims) {
  gsl_qrng *generator = gsl_qrng_alloc(gsl_qrng_sobol, static_cast<unsigned int>(ndims));
  if (generator) {
    deleteCurrentGenerator();
    m_gslGenerator = generator;
  } else {
    throw std::invalid_argument("SobolSequence::setNumberOfDimensions - "
                                "Error initializing sequence, insufficient memory.");
  }
}
 
void SobolSequence::deleteCurrentGenerator() {
  gsl_qrng_free(m_gslGenerator);
  if (m_savedGenerator) {
    gsl_qrng_free(m_savedGenerator);
  }
}
} // namespace Mantid::Kernel