[Scipy-tickets] [SciPy] #1665: Are odd-length window functions supposed to be always symmetrical?
SciPy Trac
scipy-tickets@scipy....
Wed May 30 14:51:23 CDT 2012
#1665: Are odd-length window functions supposed to be always symmetrical?
--------------------------+-------------------------------------------------
Reporter: endolith | Owner: cdavid
Type: defect | Status: new
Priority: normal | Milestone: Unscheduled
Component: scipy.signal | Version: 0.10.0
Keywords: |
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The window functions in scipy.signal have a `sym` option for producing
symmetric windows or periodic windows, but if you create a periodic window
of an odd size, it gives identical output to a symmetric window. This is
in the code, but is it right? It doesn't match Matlab's behavior, as
described [https://ccrma.stanford.edu/~jos/sasp/Matlab_Hamming_Window.html
here].
If it's right, it should be documented why it works this way
{{{
>> hamming(3) % same in Matlab and Octave
ans =
0.0800
1.0000
0.0800
>> hamming(3,'symmetric') % Matlab only
ans =
0.0800
1.0000
0.0800
>> hamming(3,'periodic') % Matlab only
ans =
0.0800
0.7700
0.7700
>> hamming(4) % same in Matlab and Octave
ans =
0.0800
0.7700
0.7700
0.0800
}}}
SciPy:
{{{
In [2]: hamming(3)
Out[2]: array([ 0.08, 1. , 0.08])
In [3]: hamming(3,sym=True)
Out[3]: array([ 0.08, 1. , 0.08])
In [4]: hamming(3,sym=False)
Out[4]: array([ 0.08, 1. , 0.08])
In [5]: hamming(4)
Out[5]: array([ 0.08, 0.77, 0.77, 0.08])
In [6]: hamming(4, sym=True)
Out[6]: array([ 0.08, 0.77, 0.77, 0.08])
In [7]: hamming(4, sym=False)
Out[7]: array([ 0.08, 0.54, 1. , 0.54])
}}}
--
Ticket URL: <http://projects.scipy.org/scipy/ticket/1665>
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