theano_fft_test.py

"""
real part
[[  2.98023224e-08   0.00000000e+00   2.98023224e-08]
 [  0.00000000e+00   0.00000000e+00   0.00000000e+00]
 [  0.00000000e+00   0.00000000e+00   0.00000000e+00]]
img part
[[  0.00000000e+00   0.00000000e+00   0.00000000e+00]
 [  0.00000000e+00   0.00000000e+00   0.00000000e+00]
 [  0.00000000e+00   2.98023224e-08   0.00000000e+00]]
real part
[[[[  9.79645666e+00   4.05509353e-01  -5.98364770e-02]
   [ -3.55478082e-01   1.95642087e+00  -2.57848706e-01]
   [ -2.45258212e-03   1.69161871e-01   1.00241494e+00]]

  [[ -4.37298611e+00  -2.96933994e+00   2.48340973e+00]
   [ -1.71750426e+00   1.20498252e+00   2.00737816e+00]
   [ -1.02334494e+00  -1.72791123e+00   1.49052728e+00]]]]
img part
[[[[ 0.          0.74940148  0.        ]
   [-0.90688866  0.68082649 -0.64381433]
   [ 0.90688866 -0.43813284  0.64381433]]

  [[ 0.         -0.73076117  0.        ]
   [ 0.29543054  0.28315097 -1.53902638]
   [-0.29543054  0.94440503  1.53902638]]]]
"""


import numpy as np
import theano
import theano.tensor as T
from theano.tensor import fft


def test1():
    x = T.matrix('x', dtype=theano.config.floatX)
    rfft = fft.rfft(x)
    f_rfft = theano.function([x], rfft)

    a = np.random.random([3,4]).astype(np.float32)
    res1 = np.fft.rfft(a)
    res2 = f_rfft(a)

    print "real part"
    print res2[..., 0] - np.real(res1)

    print "img part"
    print res2[..., 1] - np.imag(res1)


def test2():
    x = T.tensor4('x', dtype=theano.config.floatX)
    rfft = fft.rfft(x)
    f_rfft = theano.function([x], rfft)

    a = np.random.random([1,2,3,4]).astype(np.float32)
    res1 = np.fft.rfft(a)
    res2 = f_rfft(a)

    print "real part"
    print res2[..., 0] - np.real(res1)

    print "img part"
    print res2[..., 1] - np.imag(res1)


if __name__ == "__main__":
    test1()
    test2()