def test_expand_fourier_sp_odd1d(self):
"""
Test function with odd input size
"""
arr = np.random.rand(151)
arr_ft = fft.fftshift(fft.fft(fft.ifftshift(arr)))
arr_ex_ft = tools.resample_bandlimited_ft(arr_ft, (2, ))
arr_exp = fft.fftshift(fft.ifft(fft.ifftshift(arr_ex_ft))).real
max_err = np.max(np.abs(arr_exp[1::2] - arr))
self.assertTrue(max_err < 1e-14)
def test_expand_fourier_sp_even2d(self):
"""
test function with even input size
"""
arr = np.random.rand(100, 100)
arr_ft = fft.fftshift(fft.fft2(fft.ifftshift(arr)))
arr_ex_ft = tools.resample_bandlimited_ft(arr_ft, (2, 2))
arr_exp = fft.fftshift(fft.ifft2(fft.ifftshift(arr_ex_ft))).real
max_err = np.max(np.abs(arr_exp[::2, ::2] - arr))
self.assertTrue(max_err < 1e-14)
def test_expand_fourier_sp(self):
"""
Test expand_fourier_sp() function
:return:
"""
arr = np.array([[1, 2], [3, 4]])
arr_ft = fft.fftshift(fft.fft2(fft.ifftshift(arr)))
arr_ft_ex = tools.resample_bandlimited_ft(arr_ft, (2, 2))
arr_ex = fft.fftshift(fft.ifft2(fft.ifftshift(arr_ft_ex)))
self.assertTrue(
np.array_equal(
arr_ex.real,
np.array([[1, 1.5, 2, 1.5], [2, 2.5, 3, 2.5], [3, 3.5, 4, 3.5],
[2, 2.5, 3, 2.5]])))