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From: | Rik |
Subject: | [Octave-bug-tracker] [bug #45507] acos returns different results on big input values |
Date: | Thu, 09 Jul 2015 23:08:25 +0000 |
User-agent: | Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:35.0) Gecko/20100101 Firefox/35.0 |
Update of bug #45507 (project octave): Status: None => Need Info _______________________________________________________ Follow-up Comment #1: This is probably related to the correction to the phase mentioned in the NEWS file for 4.0.0 ** The trigonometric functions asin and acos return different phase values from previous versions of Octave when the input is outside the principal branch ([-1, 1]). If the real portion of the input is greater than 1 then the limit from below is taken. If the real portion is less than 1 then the limit from above is taken. This criteria is consistent with several other numerical analysis software packages. This was done because 3.8.2 did not calculate the same result as Matlab. Could you check your calculations in 3.8.2 because I don't believe they yield the same result as Matlab. For 3.8.2 on Linux with the two calculations I get acos(1e7) ans = 0.00000 - 16.81124i acos(1e8) ans = 0.00000 - 19.11383i where the sign of the imaginary portion is negative and the opposite of Matlab. _______________________________________________________ Reply to this item at: <http://savannah.gnu.org/bugs/?45507> _______________________________________________ Message sent via/by Savannah http://savannah.gnu.org/
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