WrightTools.kit.fft

WrightTools.kit.fft(xi, yi, axis=0) → Tuple[ndarray, ndarray][source]

Compute a discrete Fourier Transform along one axis of an N-dimensional array and also compute the 1D frequency coordinates of the transform. The Fourier coefficients and frequency coordinates are ordered so that the coordinates are monotonic (i.e. uses numpy.fft.fftshift).

Parameters

  • ti (1D numpy.ndarray) – Independent variable specifying data coordinates. Must be monotonic, linearly spaced data. ti.size must be equal to yi.shape[axis]

  • yi (n-dimensional numpy.ndarray) – Dependent variable. ND array with values to FFT.

  • axis (int) – axis of yi to perform FFT over

Returns

  • xi (1D numpy.ndarray) – 1D array. Conjugate coordinates to input xi. Example: if input xi is time coordinates, output xi is (cyclic) frequency coordinates.

  • yi (complex numpy.ndarray) – Transformed data. Has the same shape as the input array (yi).