[Numpy-discussion] Test error with ATLAS, Windows 64 bit

[Julian Taylor]

On 23.04.2014 21:25, Matthew Brett wrote:
> Hi,
> 
> On Tue, Apr 15, 2014 at 12:34 AM, Julian Taylor
> <jtaylor.debian at googlemail.com> wrote:
>> On Tue, Apr 15, 2014 at 4:30 AM, Matthew Brett <matthew.brett at gmail.com> wrote:
>>>
>>> It looks as though mingw-w64 is at fault, and I was confused (still
>>> am) because of the different behavior with double and a constant:
>>>
>>> #include <stdio.h>
>>> #include <math.h>
>>>
>>> int main() {
>>>     double z, i = -0.0;
>>>     printf("With double %f=%f, with constant=%f\n",
>>>    i, expm1(i), expm1(-0.));
>>> }
>>>
>>> gives:
>>>
>>> With double -0.000000=0.000000, with constant=-0.000000
>>>
>>> That was ugly to track down.
>>>
>>> What is the right way to work round this (using the numpy version
>>> instead of the system version I suppose)?
>>>
>>
>> The right way is to file a bug at mingw and get it fixed at the source.
> 
> http://sourceforge.net/p/mingw-w64/code/6594/

great thanks for reporting it.

> 
>> Additionally as this time npymath seems to be better (thats 3 bugs in
>> npymath vs 1 in mingw on my scoreboard) one could use the mingw
>> preprocessor define instead of HAVE_EXP1M to select this function from
>> npymath.
> 
> Sorry to be slow - could you unpack what you mean in this paragraph?
> Is there a way to force use of the numpy version of the function using
> environment variables or similar?
> 

I mean something along the line of attached patch, maybe you can try it.
If it works I can file a numpy PR.
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