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Re: libm-test.inc: Computing ulps near FP_ZERO.
- From: Brooks Moses <brooks_moses at mentor dot com>
- To: Carlos O'Donell <carlos at redhat dot com>
- Cc: GNU C Library <libc-alpha at sourceware dot org>, "Joseph S. Myers" <joseph at codesourcery dot com>, Andreas Jaeger <aj at suse dot com>, Thomas Schwinge <thomas at codesourcery dot com>, David Miller <davem at davemloft dot net>
- Date: Tue, 9 Apr 2013 12:50:35 -0700
- Subject: Re: libm-test.inc: Computing ulps near FP_ZERO.
- References: <51606D8A dot 9080003 at redhat dot com> <5160A4D7 dot 9080802 at codesourcery dot com> <516183BD dot 6060700 at redhat dot com> <5161AADF dot 2040403 at codesourcery dot com> <5161FA1A dot 5060100 at redhat dot com> <51620F35 dot 5080101 at codesourcery dot com> <51634CA1 dot 4050006 at redhat dot com> <51636912 dot 10702 at codesourcery dot com> <5163710F dot 9080500 at mentor dot com> <51642923 dot 9030509 at redhat dot com>
Carlos O'Donell wrote, at 4/9/2013 7:43 AM:
> I understand your point about this now.
>
> The error in expressing pi is simply an upper bound on the error.
>
> It will generate many ulp error for a precise answer to the question
> cos(M_PI_2l).
>
> I think Rich's answer is the only reasonable one, which is to compute
> what the exact answer should be.
I wouldn't agree that it's the _only_ reasonable answer, but I agree
that it is a reasonable one. :)
- Brooks