Hi,
On Mon, Apr 14, 2014 at 2:02 PM, Julian Taylor
<[email protected]> wrote:
> The official numpy mingw binaries do not have all these math issues.
> Only the VC builds do.
> As mingw is fine the functions must be somewhere in the windows API but
> no-one has contributed a fix for the VC builds to numpy yet.
I'm building with mingw-w64.
It looks like this works as expected from this test:
#include <math.h>
#include <stdio.h>
int main() {
double z;
z = expm1(-0.0);
printf("Result %f\n", z);
}
(prints -0).
as does this (modified from core/src/npymath/npy_math.c.src):
#include <stdio.h>
double npy_expm1(double x)
{
if (isinf(x) && x > 0) {
return x;
}
else {
const double u = exp(x);
if (u == 1.0) {
return x;
} else if (u - 1.0 == -1.0) {
return -1;
} else {
return (u - 1.0) * x/log(u);
}
}
}
int main() {
double z;
z = npy_expm1(-0.0);
printf("Result %f\n", z);
}
Sorry for my ignorance, but where does the `HAVE_EXPM1` symbol come from?
Cheers,
Matthew
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