python - is numpy testing assert_array_less working correctly with np.inf? -

i found strange behaviour when testing arrays infinite type.

this works good:

in [91]: np.testing.assert_array_less(5, 6)  in [92]: np.testing.assert_array_less(5, np.array([6]))  in [93]: 5 < np.inf out[93]: true 

but when using numpy testing module occurs 5 not less inf:

in [94]: np.testing.assert_array_less(5, np.array([np.inf])) --------------------------------------------------------------------------- assertionerror                            traceback (most recent call last) <ipython-input-93-c43a15aa8a1a> in <module>() ----> 1 np.testing.assert_array_less(5, np.array([np.inf]))  c:\python27\lib\site-packages\numpy\testing\utils.pyc in assert_array_less(x, y, err_msg, verbose)     911     assert_array_compare(operator.__lt__, x, y, err_msg=err_msg,     912                          verbose=verbose, --> 913                          header='arrays not less-ordered')     914     915 def runstring(astr, dict):  c:\python27\lib\site-packages\numpy\testing\utils.pyc in assert_array_compare(comparison, x, y, err_msg, verbose, header, precision)     629             if any(x_isinf) or any(y_isinf):     630                 # check +inf , -inf separately, since different --> 631                 chk_same_position(x == +inf, y == +inf, hasval='+inf')     632                 chk_same_position(x == -inf, y == -inf, hasval='-inf')     633  c:\python27\lib\site-packages\numpy\testing\utils.pyc in chk_same_position(x_id, y_id, hasval)     606                                 % (hasval), verbose=verbose, header=header,     607                                 names=('x', 'y'), precision=precision) --> 608             raise assertionerror(msg)     609     610     try:  assertionerror: arrays not less-ordered  x , y +inf location mismatch:  x: array(5)  y: array([ inf]) 

why numpy checks if infs on same positions? desired behaviour?

in [99]: np.__version__ out[99]: '1.9.3' 

as mentioned warren in comment, was/is bug in numpy. fixed in current master , fixed in upcoming version 1.13:

in [1]: import numpy np  in [2]: np.testing.assert_array_less(5, np.array([np.inf]))  in [3]: np.testing.assert_array_less(-np.inf, np.array([np.inf]))  in [4]: np.testing.assert_array_less(-np.inf, 5)  in [5]: np.testing.assert_array_less(np.inf, 5) --------------------------------------------------------------------------- assertionerror                            traceback (most recent call last) <ipython-input-5-a31a27ca3803> in <module>() ----> 1 np.testing.assert_array_less(np.inf, 5)  /xxx/lib/python2.7/site-packages/numpy/testing/utils.pyc in assert_array_less(x, y, err_msg, verbose)    1029                          verbose=verbose,    1030                          header='arrays not less-ordered', -> 1031                          equal_inf=false)    1032    1033  /xxx/lib/python2.7/site-packages/numpy/testing/utils.pyc in assert_array_compare(comparison, x, y, err_msg, verbose, header, precision, equal_nan, equal_inf)     773                                 names=('x', 'y'), precision=precision)     774             if not cond: --> 775                 raise assertionerror(msg)     776     except valueerror:     777         import traceback  assertionerror: arrays not less-ordered  (mismatch 100.0%)  x: array(inf)  y: array(5)  in [6]: np.__version__ out[6]: '1.13.0.dev0+c5e1773'