Reproduce:
import pandas as pd
import numpy as np
from scipy import fftpack
x = np.array([1.,2.,3.,4.,5.])
xs = pd.Series(x)
print x
tmp = fftpack.rfft(x)
print x
print x
tmp = fftpack.rfft(xs)
print x
"""
output:
[ 1. 2. 3. 4. 5.]
[ 1. 2. 3. 4. 5.]
[ 1. 2. 3. 4. 5.]
[ 15. -2.5 3.4409548 -2.5 0.81229924]
"""
posted also in scipy.github: https://github.com/scipy/scipy/issues/5790
Comment From: jreback
I would say this is a scipy issue. Series
is essentially a duck-like ndarray, so I don't see why it should inplace modify it.