core.utils.fft

Fast Fourier Transform related functions.

This module provides functions for computing inverse Fast Fourier Transforms.

Functions

ifftCompute the inverse Fast Fourier Transform of an array with optional

frequency domain shifting

gridr.core.utils.fft.ifft(array, shift=True, shift_after=True)[source]

Compute the inverse Fast Fourier Transform of the input array.

This function computes the inverse FFT of a 1D or 2D array and provides optional frequency domain shifting before and after the transform.

Parameters:

  • array (numpy.ndarray) – Input array (1D or 2D) representing frequency domain data with zero-frequency component at the center of the spectrum

  • shift (bool, default True) – If True, shifts the input array so that the zero-frequency component is at the beginning of the spectrum before computing the inverse FFT

  • shift_after (bool, default True) – If True, shifts the result so that the zero spatial frequency index is at the center of the output array

Returns:

The inverse FFT result with appropriate frequency domain shifting applied

Return type:

numpy.ndarray

Notes

The function assumes the input array has its zero-frequency component at the center of the spectrum. This is typical for FFT results where the DC component is positioned at the middle of the array.

Examples

>>> import numpy as np
>>> freq_data = np.random.rand(100)
>>> spatial_data = ifft(freq_data, shift=True, shift_after=True)