Hi,
This is my second post on this problem I found in numpy 1.6.1, and recently it
cam up in the latest git version (2.0.0.dev-f3e70d9). The problem is numpy
treats the native byte order ('<') as illegal while the wrong one ('>') as the
right one. The output of the attached script (bult for python 2.6 + ) is given
below (my system is a 64 bit linux on core i7. 64 bit python 2.7.2/3.2 , numpy
uses ATLAS):
$ python test_byte_order.py
a =
[[ 0.28596132 0.31658824 0.34929676]
[ 0.48739246 0.68020533 0.39616588]
[ 0.29310406 0.9584545 0.8120068 ]]
a1 =
[[ 0.28596132 0.31658824 0.34929676]
[ 0.48739246 0.68020533 0.39616588]
[ 0.29310406 0.9584545 0.8120068 ]]
(Wrong byte order on Intel CPUs):
a2 =
[[ 8.97948198e-017 1.73406416e-025 -4.25909057e+014]
[ 4.59443694e+090 7.91693101e-029 5.26959329e-135]
[ 2.93240450e+060 -2.25898860e-051 -2.06126917e+302]]
Invert a:
OK
Invert a2 (Wrong byte order!):
OK
invert a1:
Traceback (most recent call last):
File "test_byte_order.py", line 20, in <module>
b1 = N.linalg.inv(a1)
File "/usr/lib64/python2.7/site-packages/numpy/linalg/linalg.py", line 445,
in inv
return wrap(solve(a, identity(a.shape[0], dtype=a.dtype)))
File "/usr/lib64/python2.7/site-packages/numpy/linalg/linalg.py", line 326,
in solve
results = lapack_routine(n_eq, n_rhs, a, n_eq, pivots, b, n_eq, 0)
lapack_lite.LapackError: Parameter a has non-native byte order in
lapack_lite.dgesv
from __future__ import print_function
import numpy as N
a = N.random.rand(3,3)
a1 = a.newbyteorder('<')
a2 = a.newbyteorder('>')
print(' a = \n', a)
print('\n\n a1 = \n', a1)
print('\n\n(Wrong byte order on Intel CPUs):\n a2 =\n', a2)
print('\n\n Invert a:')
b = N.linalg.inv(a)
print('OK')
print('\n Invert a2 (Wrong byte order!):')
b2 = N.linalg.inv(a2)
print('OK')
print('\n invert a1:')
b1 = N.linalg.inv(a1)
print('OK')
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