[SciPy-User] Bug in ndimage.map_coordinates with mode='wrap' ?
Kurt Smith
kwmsmith at gmail.com
Mon Mar 22 13:20:05 EDT 2010
Hi,
Testing the example code in ndimage.map_coordinate's docstring, I
can't get things to work with mode='wrap'. What am I doing wrong?
In [31]: a
Out[31]:
array([[ 0., 1., 2.],
[ 3., 4., 5.],
[ 6., 7., 8.],
[ 9., 10., 11.]])
In [32]: ndimage.map_coordinates(a, [range(5), [0]*5], order=1,
mode='wrap') # should be 0, 3, 6, 9, 0 -- right?
Out[32]: array([ 0., 3., 6., 9., 3.])
In [33]: ndimage.map_coordinates(a, [[0]*4, range(4)], order=1,
mode='wrap') # should be 0, 1, 2, 0 -- right?
Out[33]: array([ 0., 1., 2., 1.])
Here's the output when extending the sampling range:
In [36]: ndimage.map_coordinates(a, [range(10), [0]*10], order=1,
mode='wrap') # should be 0, 3, 6, 9, 0, 3, 6, 9, ...
Out[36]: array([ 0., 3., 6., 9., 3., 6., 0., 3., 6., 0.])
In [37]: ndimage.map_coordinates(a, [[0]*8, range(8)], order=1, mode='wrap')
Out[37]: array([ 0., 1., 2., 1., 0., 1., 0., 1.])
If it's a bug, where can I file a report, and what can I do to help
fix it? Looks like the wrapping code is in a compiled extension
module -- I'll take a look.
Kurt
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