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Diffstat (limited to 'ml/dlib/dlib/matrix/matrix_fft_abstract.h')
| -rw-r--r-- | ml/dlib/dlib/matrix/matrix_fft_abstract.h | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/ml/dlib/dlib/matrix/matrix_fft_abstract.h b/ml/dlib/dlib/matrix/matrix_fft_abstract.h new file mode 100644 index 000000000..25cdfcaee --- /dev/null +++ b/ml/dlib/dlib/matrix/matrix_fft_abstract.h @@ -0,0 +1,118 @@ +// 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_ + |