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// Copyright (C) 2013 Davis E. King (davis@dlib.net)
// License: Boost Software License See LICENSE.txt for the full license.
#undef DLIB_FFt_ABSTRACT_Hh_
#ifdef DLIB_FFt_ABSTRACT_Hh_
#include "matrix_abstract.h"
#include "../algs.h"
namespace dlib
{
// ----------------------------------------------------------------------------------------
bool is_power_of_two (
const unsigned long& value
);
/*!
ensures
- returns true if value contains a power of two and false otherwise. As a
special case, we also consider 0 to be a power of two.
!*/
// ----------------------------------------------------------------------------------------
template <typename EXP>
typename EXP::matrix_type fft (
const matrix_exp<EXP>& data
);
/*!
requires
- data contains elements of type std::complex<> that itself contains double, float, or long double.
- is_power_of_two(data.nr()) == true
- is_power_of_two(data.nc()) == true
ensures
- Computes the 1 or 2 dimensional discrete Fourier transform of the given data
matrix and returns it. In particular, we return a matrix D such that:
- D.nr() == data.nr()
- D.nc() == data.nc()
- D(0,0) == the DC term of the Fourier transform.
- starting with D(0,0), D contains progressively higher frequency components
of the input data.
- ifft(D) == D
!*/
// ----------------------------------------------------------------------------------------
template <typename EXP>
typename EXP::matrix_type ifft (
const matrix_exp<EXP>& data
);
/*!
requires
- data contains elements of type std::complex<> that itself contains double, float, or long double.
- is_power_of_two(data.nr()) == true
- is_power_of_two(data.nc()) == true
ensures
- Computes the 1 or 2 dimensional inverse discrete Fourier transform of the
given data vector and returns it. In particular, we return a matrix D such
that:
- D.nr() == data.nr()
- D.nc() == data.nc()
- fft(D) == data
!*/
// ----------------------------------------------------------------------------------------
template <
typename T,
long NR,
long NC,
typename MM,
typename L
>
void fft_inplace (
matrix<std::complex<T>,NR,NC,MM,L>& data
);
/*!
requires
- data contains elements of type std::complex<> that itself contains double, float, or long double.
- is_power_of_two(data.nr()) == true
- is_power_of_two(data.nc()) == true
ensures
- This function is identical to fft() except that it does the FFT in-place.
That is, after this function executes we will have:
- #data == fft(data)
!*/
// ----------------------------------------------------------------------------------------
template <
typename T,
long NR,
long NC,
typename MM,
typename L
>
void ifft_inplace (
matrix<std::complex<T>,NR,NC,MM,L>& data
);
/*!
requires
- data contains elements of type std::complex<> that itself contains double, float, or long double.
- is_power_of_two(data.nr()) == true
- is_power_of_two(data.nc()) == true
ensures
- This function is identical to ifft() except that it does the inverse FFT
in-place. That is, after this function executes we will have:
- #data == ifft(data)*data.size()
- Note that the output needs to be divided by data.size() to complete the
inverse transformation.
!*/
// ----------------------------------------------------------------------------------------
}
#endif // DLIB_FFt_ABSTRACT_Hh_
|
