python - scipy.signal.resample: malfunction with even number of points? -


it seems scipy.signal.resample() makes errors when downsampling number of points. example, if upsample function multiple of original points , downsample again, should original function back. 

from scipy import signal import numpy np  def test_resample(n1,n2): # upsample n1 n2 points ,     x1=np.arange(n1)     y1=np.sin(x1)     y2,x2=signal.resample(y1,n2,x1)       y3,x3=signal.resample(y2,n1,x2)       print np.allclose(y1,y3)

but fails when lower number of points even:

test_resample(10,20)     false  test_resample(11,22)     true  test_resample(11,33)     true

the problem occurs @ downsampling step. errors large, @ least several percent functions tested.

update of 4/8/17: seems coding error. reported details of bug here.


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