Gentoo Archives: gentoo-amd64

From: Frank Peters <frank.peters@×××××××.net>
To: gentoo-amd64@l.g.o
Subject: Re: [gentoo-amd64] Possible Math Problem - Request For Verification
Date: Sun, 26 Jun 2011 01:30:17
Message-Id: 20110625212856.b565b9da.frank.peters@comcast.net
In Reply to: Re: [gentoo-amd64] Possible Math Problem - Request For Verification by Marc Joliet
1 On Sun, 26 Jun 2011 01:54:53 +0200
2 Marc Joliet <marcec@×××.de> wrote:
3
4 >
5 > Then according to the results above my machine is apparently OK. (I guess I
6 > really should finally read about IEEE floating point more thoroughly, I've been
7 > planning to do that for a while now.)
8 >
9
10 These tests are extreme. The accuracy is supposedly less than 1 ulp
11 (unit in the last place).
12
13 You can check the *output files in the results directory to see
14 more information on the error. For example, the COS(X) error
15 file is ccos_DP.output and contains the maximum positive and
16 maximum negative errors in ulps. On my machine these are 1.567
17 and -3.74 ulps, so the error is small.
18
19 In contrast, the LOG(X) function passes the test but it still shows
20 errors of 0.532 and -0.531 ulps.
21
22 Frank Peters