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Re: libm-test.inc: Computing ulps near FP_ZERO.
- From: "Carlos O'Donell" <carlos at redhat dot com>
- To: Rich Felker <dalias at aerifal dot cx>
- Cc: Brooks Moses <brooks_moses at mentor dot com>, 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, 09 Apr 2013 11:39:44 -0400
- 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> <20130409020954 dot GT20323 at brightrain dot aerifal dot cx>
On 04/08/2013 10:09 PM, Rich Felker wrote:
> I'm a bit confused about this whole discussion. If the test is
> cos(M_PI_2) then according to Wolfram Alpha,
> cos(1.5707963267948965579989817342720925807952880859375), where that
> argument is the exact value of M_PI_2, evaluates to approximately:
>
> 6.123233995736765886130329661375001... Ã 10^-17
Could you do me a favour and compute:
cpow (0.75 + 1.25 i, 0.75 + 1.25 i)?
Could you also compute:
cosf(M_PI_2)?
That is to say the 32-bit float variant with rounding for M_PI_2 to
float?
Cheers,
Carlos.