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 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.