keras/src/backend/numpy/math.py/irfft
def irfft(x, fft_length=None):
    complex_input = _get_complex_tensor_from_tuple(x)
    # numpy always outputs float64, so we need to recast the dtype
    return np.fft.irfft(
        complex_input, n=fft_length, axis=-1, norm="backward"
    ).astype(x[0].dtype)