fft2

Functions

int main(int argc, char *argv[])

fft2 [ option ] [ infile ]

• -l int

  • FFT length \((1 \le L)\)

• -r int

  • number of rows \((1 \le M \le L)\)

• -c int

  • number of columns \((1 \le N \le L)\)

• -o int

  • output format

    • 0 real and imaginary parts

    • 1 real part

    • 2 imaginary part

    • 3 amplitude spectrum

    • 4 power spectrum

• -p int

  • output style

    • 0 standard

    • 1 transposed

    • 2 transposed with boundary

    • 3 quadrand with boundary

• infile str

  • double-type 2D data sequence

• stdout

  • double-type 2D FFT sequence

The input and output are arranged as follows.

The output are reshaped by -p option.

Parameters

• argc – [in] Number of arguments.

• argv – [in] Argument vector.

Returns

0 on success, 1 on failure.

See also

fft ifft2 fftr2

class sptk::TwoDimensionalFastFourierTransform

Calculate 2D DFT of complex-valued input data.

The inputs are two \(M \times N\) matrices that represent real and imaginary parts:

\[ \begin{array}{cc} \mathrm{Re}(\boldsymbol{x}), & \mathrm{Im}(\boldsymbol{x}). \end{array} \]

The outputs are two \(L \times L \) matrices:

\[ \begin{array}{cccc} \mathrm{Re}(\boldsymbol{X}), & \mathrm{Im}(\boldsymbol{X}), \end{array} \]

where \(L\) is the FFT length and must be a power of two.

Public Functions

TwoDimensionalFastFourierTransform(int num_row, int num_column, int fft_length)

Parameters

• num_row – [in] Number of rows, \(M\).

• num_column – [in] Number of columns, \(N\).

• fft_length – [in] FFT length, \(L\).

inline int GetNumRow() const

Returns

Number of rows of input.

inline int GetNumColumn() const

Returns

Number of columns of input.

inline int GetFftLength() const

Returns

FFT length.

inline bool IsValid() const

Returns

True if this object is valid.

bool Run(const Matrix &real_part_input, const Matrix &imag_part_input, Matrix *real_part_output, Matrix *imag_part_output, TwoDimensionalFastFourierTransform::Buffer *buffer) const

Parameters

• real_part_input – [in] Real part of input.

• imag_part_input – [in] Imaginary part of input.

• real_part_output – [out] Real part of output.

• imag_part_output – [out] Imaginary part of output.

• buffer – [out] Buffer.

Returns

True on success, false on failure.

bool Run(Matrix *real_part, Matrix *imag_part, TwoDimensionalFastFourierTransform::Buffer *buffer) const

Parameters

• real_part – [inout] Real part.

• imag_part – [inout] Imaginary part.

• buffer – [out] Buffer.

Returns

True on success, false on failure.

class Buffer

Buffer for TwoDimensionalFastFourierTransform class.