def types(x):
warnings.warn("math.types is deprecated. Use struct.dtype isntead.",
DeprecationWarning)
try:
return math.dtype(x)
except NoBackendFound:
return type(x)
def fourier_poisson(tensor, times=1):
""" Inverse operation to `fourier_laplace`. """
frequencies = math.fft(math.to_complex(tensor))
k = fftfreq(math.staticshape(tensor)[1:-1], mode='square')
fft_laplace = -(2 * np.pi)**2 * k
fft_laplace[(0, ) * math.ndims(k)] = np.inf
return math.cast(
math.real(
math.ifft(math.divide_no_nan(frequencies, fft_laplace**times))),
math.dtype(tensor))