TimeAtSampleStrategyElastic.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 +
#include <utility>
 
#include "MantidAPI/MatrixWorkspace.h"
#include "MantidAPI/SpectrumInfo.h"
#include "MantidAlgorithms/TimeAtSampleStrategyElastic.h"
#include "MantidGeometry/IComponent.h"
#include "MantidGeometry/Instrument.h"
#include "MantidGeometry/Instrument/ReferenceFrame.h"
 
using namespace Mantid::Kernel;
using namespace Mantid::Geometry;
using namespace Mantid::API;
 
namespace Mantid::Algorithms {
 
TimeAtSampleStrategyElastic::TimeAtSampleStrategyElastic(Mantid::API::MatrixWorkspace_const_sptr ws)
    : m_ws(std::move(ws)), m_spectrumInfo(m_ws->spectrumInfo()),
      m_beamDir(m_ws->getInstrument()->getReferenceFrame()->vecPointingAlongBeam()) {}
 
Correction TimeAtSampleStrategyElastic::calculate(const size_t &workspace_index) const {
 
  // Calculate TOF ratio
  const double L1s = m_spectrumInfo.l1();
  double scale;
  if (m_spectrumInfo.isMonitor(workspace_index)) {
    double L1m = m_beamDir.scalar_prod(m_spectrumInfo.sourcePosition() - m_spectrumInfo.position(workspace_index));
    scale = std::abs(L1s / L1m);
  } else {
    scale = L1s / (L1s + m_spectrumInfo.l2(workspace_index));
  }
 
  return Correction(0., scale);
}
 
} // namespace Mantid::Algorithms