FFT.h

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// Mantid Repository : https://github.com/mantidproject/mantid
//
// Copyright © 2008 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 +
#pragma once
 
//----------------------------------------------------------------------
// Includes
//----------------------------------------------------------------------
#include "MantidAPI/Algorithm.h"
#include "MantidAPI/Workspace_fwd.h"
#include "MantidAlgorithms/DllConfig.h"
#include "MantidHistogramData/BinEdges.h"
#include "MantidHistogramData/Points.h"
#include "MantidKernel/cow_ptr.h"
#include <gsl/gsl_fft_complex.h>
 
namespace Mantid {
 
namespace HistogramData {
class HistogramX;
}
 
namespace Algorithms {
 
class MANTID_ALGORITHMS_DLL FFT : public API::Algorithm {
public:
  virtual ~FFT() = default;
  const std::string name() const override { return "FFT"; }
  const std::string summary() const override { return "Performs complex Fast Fourier Transform"; }
 
  int version() const override { return 1; }
  const std::vector<std::string> seeAlso() const override {
    return {"ExtractFFTSpectrum", "FFTDerivative", "MaxEnt", "RealFFT", "SassenaFFT", "FFTSmooth"};
  }
  const std::string category() const override { return "Arithmetic\\FFT"; }
 
protected:
  std::map<std::string, std::string> validateInputs() override;
 
private:
  // Overridden Algorithm methods
  void init() override;
  void exec() override;
 
  void createUnitsLabels(double &df);
 
  // Perform forward transformation
  void transformForward(std::vector<double> &data, const int xSize, const int ySize, const int dys,
                        const bool addPositiveOnly, const bool centerShift, const bool isComplex, const int iReal,
                        const int iImag, const double df, const double dx);
  // Perform backward transformation
  void transformBackward(std::vector<double> &data, const int xSize, const int ySize, const int dys,
                         const bool centerShift, const bool isComplex, const int iReal, const int iImag,
                         const double df);
 
  void setupTAxis(const int nOut, const bool addPositiveOnly);
  bool areBinWidthsUneven(const HistogramData::BinEdges &xBins) const;
  double getPhaseShift(const HistogramData::Points &xPoints);
 
private:
  Mantid::API::MatrixWorkspace_const_sptr m_inWS;
  Mantid::API::MatrixWorkspace_const_sptr m_inImagWS;
  Mantid::API::MatrixWorkspace_sptr m_outWS;
  gsl_fft_complex_wavetable *m_wavetable;
  gsl_fft_complex_workspace *m_workspace;
  int m_iIm;
  int m_iRe;
  int m_iAbs;
};
 
} // namespace Algorithms
} // namespace Mantid