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Groups > comp.lang.forth > #50378
| From | "HAA" <someone@microsoft.com> |
|---|---|
| Newsgroups | comp.lang.forth |
| Subject | fatan2 2012 |
| Date | 2016-08-22 13:44 +1000 |
| Organization | Aioe.org NNTP Server |
| Message-ID | <npdse1$1s5g$1@gioia.aioe.org> (permalink) |
From the PDF ... 12.6.2.1489 FATAN2 "f-a-tan-two" FLOATING EXT ( F: r1 r2 -- r3 ) or ( r1 r2 -- r3 ) r3 is the principal radian angle (between -pi and pi ) whose tangent is r1 / r2 . A system that returns false for "-0E 0E 0E F~" shall return a value (approximating) -pi when r1 = 0E and r2 is negative. Gforth 0.7.0, Copyright (C) 1995-2008 Free Software Foundation, Inc. Gforth comes with ABSOLUTELY NO WARRANTY; for details type `license' Type `bye' to exit -0e 0e 0e f~ . 0 ok 0e -1e fatan2 fs. 3.14159265358979E0 ok Same for Win32Forth What should I do now? I assume there is an error in the test as supplied. BTW there several 'corner case' tests that could be applied to FATAN2. Singling out one with no explanation is only going to leave readers with questions when it does fail i.e. what's so special about *this* test. Then there is the reliance on the notorious F~ whose results can be right or wrong depending upon your expectations e.g. SwiftForth i386-Win32 3.6.2 04-Apr-2016 0e pad f! pad 1 floats dump 4809E8 00 00 00 00 00 00 00 00 ........ ok 0e fnegate pad f! pad 1 floats dump 4809E8 00 00 00 00 00 00 00 80 ........ ok 0e fdup fnegate 0e f~ . -1 ok 0e fs. 0.0000000E+00 ok 0e fnegate fs. 0.0000000E+00 ok
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fatan2 2012 "HAA" <someone@microsoft.com> - 2016-08-22 13:44 +1000
Re: fatan2 2012 Paul Rubin <no.email@nospam.invalid> - 2016-08-21 21:01 -0700
Re: fatan2 2012 peter.m.falth@gmail.com - 2016-08-22 00:42 -0700
Re: fatan2 2012 anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-08-22 10:00 +0000
Re: fatan2 2012 "HAA" <someone@microsoft.com> - 2016-08-23 12:51 +1000
Re: fatan2 2012 anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-08-23 11:11 +0000
Re: fatan2 2012 "HAA" <someone@microsoft.com> - 2016-08-25 02:16 +1000
Re: fatan2 2012 albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-02 18:03 +0200
Re: fatan2 2012 Paul Rubin <no.email@nospam.invalid> - 2016-09-02 12:02 -0700
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