Fft.h

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//-----------------------------------------------------------------------bl-
//--------------------------------------------------------------------------
//
// QUESO - a library to support the Quantification of Uncertainty
// for Estimation, Simulation and Optimization
//
// Copyright (C) 2008-2017 The PECOS Development Team
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the Version 2.1 GNU Lesser General
// Public License as published by the Free Software Foundation.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc. 51 Franklin Street, Fifth Floor,
// Boston, MA  02110-1301  USA
//
//-----------------------------------------------------------------------el-

#ifndef UQ_FFT_H
#define UQ_FFT_H

#include <queso/Environment.h>
#include <vector>
#include <complex>

namespace QUESO {

/* If the function to be transformed is not
    harmonically related to the sampling frequency, the response of an FFT looks like a sinc
    function (although the integrated power is still correct). Aliasing (also known as leakage)
    can be reduced by apodization using an apodization function. However, aliasing reduction
    is at the expense of broadening the spectral response.*/

template <class T>
class Fft
{
public:

  Fft(const BaseEnvironment& env);

  ~Fft();



  void forward(const std::vector<T>&                     data,
                     unsigned int                        fftSize,
                     std::vector<std::complex<double> >& result);


  void inverse(const std::vector<T>&                     data,
                     unsigned int                        fftSize,
                     std::vector<std::complex<double> >& result);
private:
  //void allocTables(unsigned int fftSize);
  //void freeTables ();

  const BaseEnvironment& m_env;
  //unsigned int               m_fftSize;

  //gsl_fft_real_workspace*    m_realWkSpace;
  //gsl_fft_real_wavetable*    m_realWvTable;
  //gsl_fft_complex_workspace* m_complexWkSpace;
  //gsl_fft_complex_wavetable* m_complexWvTable;
};

}  // End namespace QUESO

#endif // UQ_FFT_H