The following example works with NumPy but not with mkl_fft. ```python import numpy x = numpy.random.random((30, 20, 10)) numpy.fft.fftn(x, s=(10, 20, 10), axes=(0, 1, 2)).shape # (10, 20, 10) import mkl_fft, numpy x = numpy.random.random((30, 20, 10)) mkl_fft.irfftn(x, s=(10, 20, 10), axes=(0, 1, 2)).shape # ... # ValueError: could not broadcast input array from shape (10,20) into shape (30,20) ```