On Monday, April 14, 2014, Matthew Brett <matthew.br...@gmail.com> wrote:
> Hi, > > On Mon, Apr 14, 2014 at 12:12 PM, Warren Weckesser > <warren.weckes...@gmail.com <javascript:;>> wrote: > > > > On Mon, Apr 14, 2014 at 2:59 PM, Matthew Brett > > <matthew.br...@gmail.com<javascript:;> > > > > wrote: > >> > >> Hi, > >> > >> With Carl Kleffner, I am trying to build a numpy 1.8.1 wheel for > >> Windows 64-bit, and latest stable ATLAS. > >> > >> It works fine, apart from the following test failure: > >> > >> ====================================================================== > >> FAIL: test_special (test_umath.TestExpm1) > >> ---------------------------------------------------------------------- > >> Traceback (most recent call last): > >> File "C:\Python27\lib\site-packages\numpy\core\tests\test_umath.py", > >> line 329, in test_special > >> assert_equal(ncu.expm1(-0.), -0.) > >> File "C:\Python27\lib\site-packages\numpy\testing\utils.py", line > >> 311, in assert_equal > >> raise AssertionError(msg) > >> AssertionError: > >> Items are not equal: > >> ACTUAL: 0.0 > >> DESIRED: -0.0 > >> > >> Has anyone seen this? Is it in fact necessary that expm1(-0.) return > >> -0 instead of 0? > >> > > > > > > What a cowinky dink. This moring I ran into this issue in a scipy pull > > request (https://github.com/scipy/scipy/pull/3547), and I asked about > this > > comparison failing on the mailing list a few hours ago. In the pull > > request, the modified function returns -0.0 where it used to return 0.0, > and > > the test for the value 0.0 failed. My work-around was to use > > `assert_array_equal` instead of `assert_equal`. The array comparison > > functions treat the values -0.0 and 0.0 as equal. `assert_equal` has > code > > that checks for signed zeros, and fails if they are not the same sign. > > Yes, sorry, I should have mentioned that I saw your post too. I'd > live to use that workaround, but it looks like the teste against -0 is > intentional, and I was hoping for help understanding. > > The relevant two lines of the test are: > > assert_equal(ncu.expm1(0.), 0.) > assert_equal(ncu.expm1(-0.), -0.) > > Julian - I think this one is for you - as the author of these lines: > > f53ab41a numpy/core/tests/test_umath.py (Julian Taylor > 2014-03-02 02:55:30 +0100 329) assert_equal(ncu.expm1(-0.), > -0.) > > Can you say why you wanted -0 specifically? Any clue as to why ATLAS > 64 bit may give 0 instead? > > Cheers, > > Matthew > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@scipy.org <javascript:;> > http://mail.scipy.org/mailman/listinfo/numpy-discussion > I think this is a real bug in the version of exp1m in core/src/npymath/npy_math.c.src that's being used since your windows build couldn't find a system version of exp1m to use. Eric
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