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

Julian Taylor jtaylor.debian at googlemail.com
Tue Apr 15 03:34:57 EDT 2014

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.

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

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