test_fft.py running
using: from numpy.fft import fft
using: from numpy.fft import ifft
from numpy.matlib import real
a=
[0.0, 0.70709999999999995, 1.0, 0.70709999999999995, 0.0, -0.70709999999999995, -1.0, -0.70709999999999995]
b=fft(a)  complex  =
[  0.00000000e+00 +0.00000000e+00j  -3.20820844e-15 -3.99998082e+00j
   0.00000000e+00 +0.00000000e+00j   9.95839695e-17 +1.91800920e-05j
   0.00000000e+00 +0.00000000e+00j  -9.95839695e-17 -1.91800920e-05j
   0.00000000e+00 +0.00000000e+00j   3.20820844e-15 +3.99998082e+00j]
c=inverse fft ifft(b)  complex =
[ 0.0000 +0.00000000e+00j  0.7071 +2.77555756e-16j  1.0000 -8.26948102e-16j
  0.7071 -2.77555756e-16j  0.0000 +0.00000000e+00j -0.7071 -2.77555756e-16j
 -1.0000 +8.26948102e-16j -0.7071 +2.77555756e-16j]
d=real(c) just real part
[ 0.      0.7071  1.      0.7071  0.     -0.7071 -1.     -0.7071]
e=abs(c)  absolute value
[ 0.      0.7071  1.      0.7071  0.      0.7071  1.      0.7071]