// This file is part of Eigen, a lightweight C++ template library
// for linear algebra. 
//
// Copyright (C) 2009 Mark Borgerding mark a borgerding net
//
// Eigen is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 3 of the License, or (at your option) any later version.
//
// Alternatively, you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 of
// the License, or (at your option) any later version.
//
// Eigen 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 or the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License and a copy of the GNU General Public License along with
// Eigen. If not, see <http://www.gnu.org/licenses/>.

#ifndef EIGEN_FFT_H
#define EIGEN_FFT_H

#include <complex>
#include <vector>
#include <map>

#ifdef EIGEN_FFTW_DEFAULT
// FFTW: faster, GPL -- incompatible with Eigen in LGPL form, bigger code size
#  include <fftw3.h>
   namespace Eigen {
#    include "src/FFT/ei_fftw_impl.h"
     //template <typename T> typedef struct ei_fftw_impl  default_fft_impl; this does not work
     template <typename T> struct default_fft_impl : public ei_fftw_impl<T> {};
   }
#elif defined EIGEN_MKL_DEFAULT
// TODO 
// intel Math Kernel Library: fastest, commercial -- may be incompatible with Eigen in GPL form
   namespace Eigen {
#    include "src/FFT/ei_imklfft_impl.h"
     template <typename T> struct default_fft_impl : public ei_imklfft_impl {};
   }
#else
// ei_kissfft_impl:  small, free, reasonably efficient default, derived from kissfft
//
  namespace Eigen {
#   include "src/FFT/ei_kissfft_impl.h"
     template <typename T> 
       struct default_fft_impl : public ei_kissfft_impl<T> {};
  }
#endif

namespace Eigen {

template <typename _Scalar,
         typename _Impl=default_fft_impl<_Scalar> >
class FFT
{
  public:
    typedef _Impl impl_type;
    typedef typename impl_type::Scalar Scalar;
    typedef typename impl_type::Complex Complex;

    FFT(const impl_type & impl=impl_type() ) :m_impl(impl) { }

    template <typename _Input>
    void fwd( Complex * dst, const _Input * src, int nfft)
    {
        m_impl.fwd(dst,src,nfft);
    }

    template <typename _Input>
    void fwd( std::vector<Complex> & dst, const std::vector<_Input> & src) 
    {
        dst.resize( src.size() );
        fwd( &dst[0],&src[0],src.size() );
    }

    template<typename InputDerived, typename ComplexDerived>
    void fwd( MatrixBase<ComplexDerived> & dst, const MatrixBase<InputDerived> & src)
    {
        EIGEN_STATIC_ASSERT_VECTOR_ONLY(InputDerived)
        EIGEN_STATIC_ASSERT_VECTOR_ONLY(ComplexDerived)
        EIGEN_STATIC_ASSERT_SAME_VECTOR_SIZE(ComplexDerived,InputDerived) // size at compile-time
        EIGEN_STATIC_ASSERT((ei_is_same_type<typename ComplexDerived::Scalar, Complex>::ret),
                            YOU_MIXED_DIFFERENT_NUMERIC_TYPES__YOU_NEED_TO_USE_THE_CAST_METHOD_OF_MATRIXBASE_TO_CAST_NUMERIC_TYPES_EXPLICITLY)
        EIGEN_STATIC_ASSERT(int(InputDerived::Flags)&int(ComplexDerived::Flags)&DirectAccessBit,
                            THIS_METHOD_IS_ONLY_FOR_EXPRESSIONS_WITH_DIRECT_MEMORY_ACCESS_SUCH_AS_MAP_OR_PLAIN_MATRICES)
        dst.derived().resize( src.size() );
        fwd( &dst[0],&src[0],src.size() );
    }

    template <typename _Output>
    void inv( _Output * dst, const Complex * src, int nfft)
    {
        m_impl.inv( dst,src,nfft );
    }

    template <typename _Output>
    void inv( std::vector<_Output> & dst, const std::vector<Complex> & src) 
    {
        dst.resize( src.size() );
        inv( &dst[0],&src[0],src.size() );
    }

    template<typename OutputDerived, typename ComplexDerived>
    void inv( MatrixBase<OutputDerived> & dst, const MatrixBase<ComplexDerived> & src)
    {
        EIGEN_STATIC_ASSERT_VECTOR_ONLY(OutputDerived)
        EIGEN_STATIC_ASSERT_VECTOR_ONLY(ComplexDerived)
        EIGEN_STATIC_ASSERT_SAME_VECTOR_SIZE(ComplexDerived,OutputDerived) // size at compile-time
        EIGEN_STATIC_ASSERT((ei_is_same_type<typename ComplexDerived::Scalar, Complex>::ret),
                            YOU_MIXED_DIFFERENT_NUMERIC_TYPES__YOU_NEED_TO_USE_THE_CAST_METHOD_OF_MATRIXBASE_TO_CAST_NUMERIC_TYPES_EXPLICITLY)
        EIGEN_STATIC_ASSERT(int(OutputDerived::Flags)&int(ComplexDerived::Flags)&DirectAccessBit,
                            THIS_METHOD_IS_ONLY_FOR_EXPRESSIONS_WITH_DIRECT_MEMORY_ACCESS_SUCH_AS_MAP_OR_PLAIN_MATRICES)
        dst.derived().resize( src.size() );
        inv( &dst[0],&src[0],src.size() );
    }

    // TODO: multi-dimensional FFTs
    
    // TODO: handle Eigen MatrixBase
     // ---> i added fwd and inv specializations above + unit test, is this enough? (bjacob)

    impl_type & impl() {return m_impl;}
  private:
    impl_type m_impl;
};
}
#endif
/* vim: set filetype=cpp et sw=2 ts=2 ai: */