`scipy.fft._realtransforms:idctn`

Signature

def idctn(x, type = 2, s = None, axes = None, norm = None, overwrite_x = False, workers = None, *, orthogonalize = None)

Return multidimensional Inverse Discrete Cosine Transform along the specified axes.

x : array_like: The input array.
type : {1, 2, 3, 4}, optional: Type of the DCT (see Notes). Default type is 2.
s : int or array_like of ints or None, optional: The shape of the result. If both s and axes (see below) are None, s is x.shape; if s is None but axes is not None, then s is numpy.take(x.shape, axes, axis=0). If s[i] > x.shape[i], the ith dimension of the input is padded with zeros. If s[i] < x.shape[i], the ith dimension of the input is truncated to length s[i]. If any element of s is -1, the size of the corresponding dimension of x is used.
axes : int or array_like of ints or None, optional: Axes over which the IDCT is computed. If not given, the last len(s) axes are used, or all axes if s is also not specified.
norm : {"backward", "ortho", "forward"}, optional: Normalization mode (see Notes). Default is "backward".
overwrite_x : bool, optional: If True, the contents of x can be destroyed; the default is False.
workers : int, optional: Maximum number of workers to use for parallel computation. If negative, the value wraps around from os.cpu_count(). See fft for more details.
orthogonalize : bool, optional: Whether to use the orthogonalized IDCT variant (see Notes). Defaults to True when norm="ortho" and False otherwise.
versionadded 1.8.0

For full details of the IDCT types and normalization modes, as well as references, see idct.

import numpy as np
from scipy.fft import dctn, idctn
rng = np.random.default_rng()
y = rng.standard_normal((16, 16))
np.allclose(y, idctn(dctn(y)))

✓

True