Re: Test suite failure on Cygwin: atan2_1.f90

[Jerry DeLisle <jvdelisle at verizon dot net>]

On 09/14/2009 09:06 PM, Steve Kargl wrote:
> On Mon, Sep 14, 2009 at 08:50:50PM -0700, Jerry DeLisle wrote:
> > I have found that atan2_1.f90 fails on Cygwin on the following code:
> >
> > do i = 1, 10
> >    if(atan(1.0,  i/10.0)  -atan2(1.0,  i/10.)    /= 0.0)   call abort()
> >    if(atan(1.0d0,i/10.0d0)-atan2(1.0d0,i/10.0d0) /= 0.0d0) call abort()
> > end do
> >
> > Notice that the test case is looking for an exact answer.  This test can
> > pass if we use epsilon() in the criteria.
> >
> > Further, I noticed that if I use -ffloat-store (ye ole pr323) I do get
> > the exact results.  Should we change the test to accept some error or
> > add a target specific dg-option -ffloat-store for the Cygwin target?
>
> It's probably acceptable to accept some multiple
> of epsilon in this case.  The Fortran standard is
> fairly clear that an intrinsic function returns a
> processor-dependent approximation to these functions.
> If cygwins are concerned about the quality of the
> cygwin/windows math library, let them run ucbtest
> and fix it.

I am happy to report that this is the only hiccup for gfortran on 
Cygwin-1.7.  Outstanding!  Perfect score really.

This says a lot for the Cygwin team on the new 1.7.

Cheers,

Jerry