Bug#746013: Investigating i386 issues with libmatheval

[Neil Williams]

On Mon, 06 Oct 2014 23:41:16 +0200
Julian Taylor <jtaylor.debian at googlemail.com> wrote:

> On 06.10.2014 23:34, Neil Williams wrote:
> > Something odd with the *386 builds, i386, kfreebsd-i386 and
> > hurd-i386:
> > 
> > i386 chroot:
> > -1.3130352854993315
> > +1.3130352854993312
> > 
> > Other 32bit architectures don't have a problem. 
> > 
> 
> thats very expected, i386 numerical precision depends on compiler
> optimizations as the fpu has 80 bit width while double has 64.
> You need to bump the error bounds or use special flags like
> -ffloat-store or -fpmath=sse to avoid it.

OK, thanks. We're going to tweak the patch to use deterministic
precision, based on the highest precision available on all current
architectures.

-- 


Neil Williams
=============
http://www.linux.codehelp.co.uk/

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