Hi, On Wed, Jun 20, 2012 at 1:56 PM, Travis Oliphant <travis@continuum.io> wrote:
This looks like a problem with comparisons of floating point numbers rather than a byteswapping problem per-say. Try to use an almost equal comparison instead.
Is that right - that the byteswapped versions might not be strictly equal to identical numbers but not byteswapped? But I should maybe have been clearer - they also subtract wrongly: <script> import numpy as np arr = np.arange(10, dtype=np.complex256) bs_arr = arr.byteswap().newbyteorder('S') print arr print bs_arr print arr - bs_arr print arr - bs_arr print arr - bs_arr </script> (np-devel)[mb312@joshlegacy ~/tmp]$ python funny_bs.py [ 0.0+0.0j 1.0+0.0j 2.0+0.0j 3.0+0.0j 4.0+0.0j 5.0+0.0j 6.0+0.0j 7.0+0.0j 8.0+0.0j 9.0+0.0j] [ 0.0+0.0j 1.0+0.0j 2.0+0.0j 3.0+0.0j 4.0+0.0j 5.0+0.0j 6.0+0.0j 7.0+0.0j 8.0+0.0j 9.0+0.0j] [ 0.0+0.0j 1.0+0.0j 2.0+0.0j 3.0+0.0j 4.0+0.0j 5.0+0.0j 6.0+0.0j 7.0+0.0j 8.0+0.0j 9.0+0.0j] [ 0.0+0.0j 1.0+0.0j 2.0+0.0j 3.0+0.0j 4.0+0.0j 5.0+0.0j 6.0+0.0j 7.0+0.0j 8.0+0.0j 9.0+0.0j] [ 0.0+0.0j 1.0+0.0j 2.0+0.0j 3.0+0.0j 4.0+0.0j 5.0+0.0j 6.0+0.0j 7.0+0.0j 8.0+0.0j 9.0+0.0j] (wrong) (np-devel)[mb312@joshlegacy ~/tmp]$ python funny_bs.py [ 0.0+0.0j 1.0+0.0j 2.0+0.0j 3.0+0.0j 4.0+0.0j 5.0+0.0j 6.0+0.0j 7.0+0.0j 8.0+0.0j 9.0+0.0j] [ 0.0+0.0j 1.0+0.0j 2.0+0.0j 3.0+0.0j 4.0+0.0j 5.0+0.0j 6.0+0.0j 7.0+0.0j 8.0+0.0j 9.0+0.0j] [ 0.0+0.0j 0.0+0.0j 0.0+0.0j 0.0+0.0j 0.0+0.0j 0.0+0.0j 0.0+0.0j 0.0+0.0j 0.0+0.0j 0.0+0.0j] [ 0.0+0.0j 0.0+0.0j 0.0+0.0j 0.0+0.0j 0.0+0.0j 0.0+0.0j 0.0+0.0j 0.0+0.0j 0.0+0.0j 0.0+0.0j] [ 0.0+0.0j 0.0+0.0j 0.0+0.0j 0.0+0.0j 0.0+0.0j 0.0+0.0j 0.0+0.0j 0.0+0.0j 0.0+0.0j 0.0+0.0j] (right) See you, Matthew