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[Octave-bug-tracker] [bug #44310] log and functions which use log return
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From: |
Michael Godfrey |
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Subject: |
[Octave-bug-tracker] [bug #44310] log and functions which use log return incorrect result |
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Date: |
Wed, 25 Feb 2015 22:34:26 +0000 |
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User-agent: |
Mozilla/5.0 (X11; Fedora; Linux x86_64; rv:35.0) Gecko/20100101 Firefox/35.0 |
Follow-up Comment #4, bug #44310 (project octave):
The problem appears to be with the line:
double complex an = clog(xp/xm)/2.0;
replacing this by:
double complex ans = (clog(xp) - clog(xm))/2.0;
corrects the problem with atanh(0 -10i)
as shown below. Using 2 calls to clog is less
efficient, but gets the right answer. I do not
know whether the problem came about due to a change in
the code produced for for xp/xm, or replacing clog(xp) - clog(xm)
by clog(xp/xm).
The attached patch tests for this error in mappers.cc
(file #33188)
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