[Octave-bug-tracker] [bug #45507] acos returns different results on big input values

[Lachlan Andrew]

Follow-up Comment #7, bug #45507 (project octave):

Thanks for checking, Hartmut.

The problem with the previous patch was the use of 'abs' instead of 'fabs'.

The attached patch passes Marco's tests.  Thanks Marco! That script was really
helpful, both as a benchmark and showing how to avoid the cancellations.

It also passes  make check  (although it slightly widens the tolerance on one
test).

I've tried to avoid the double sqrt; the patch could be made slightly shorter
and presumably slightly slower by using the double square root.  That is a
matter of taste for whoever applies the patch.

(file #36198)
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File name: bug_45507.v2.cset              Size:6 KB


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