[Numpy-discussion] Solaris Sparc build broken
Charles R Harris
charlesr.harris at gmail.com
Thu Nov 5 01:57:54 EST 2009
On Wed, Nov 4, 2009 at 11:30 PM, David Cournapeau <
david at ar.media.kyoto-u.ac.jp> wrote:
> Charles R Harris wrote:
>
> >
> > I don't think it's that bad. Leaving out the ppc and sticking to ieee,
> > there is only double precision, extended precision and quad precision
> > versions of long double and they are easily determined at run time.
>
> How would you determine this at runtime ?
>
>
Excepting the PPC, just loop adding a number to one, dividing it by two at
each iteration, and stop when the result is equal to one. There has been a
version of that in the scipy zeros module since forever.
PyMODINIT_FUNC init_zeros(void)
{
double tol;
/* Determine relative precision of doubles, assumes binary */
for(tol = 1; tol + 1 != 1; tol /= 2);
scipy_zeros_rtol = 2*tol;
Py_InitModule("_zeros", Zerosmethods);
}
Or you could just do byte comparisons against known numbers.
Chuck
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