Wed 22 Feb 2006 08:39:36 PM UTC, original submission:
GCL 2.6.7 seems to have wrong behavior for branch cut of atanh.
I also checked acos and asin and those 2 seem OK.
(1) acos and asin: CLHS says
(http://www.lispworks.com/documentation/HyperSpec/Body/f_asin_.htm)
that the branch cut on [1, \infty) is continuous w/ 4th quadrant
and on (-\infty, -1] is continuous w/ 2nd quadrant.
GCL: conforms to spec
(2) atanh: CLHS says
(http://www.lispworks.com/documentation/HyperSpec/Body/f_sinh_.htm)
that the branch cut on [1, \infty) is continuous w/ 1st quadrant
and on (-\infty, -1] is continuous w/ 3rd quadrant.
GCL: continuous w/ 4th and 2nd quadrants respectively
PS. Here's a test script:
(cl:asin #C(2.5 0.01))
(cl:asin 2.5)
(cl:asin #C(2.5 -0.01))
(cl:asin #C(-2.5 0.01))
(cl:asin -2.5)
(cl:asin #C(-2.5 -0.01))
(cl:acos #C(2.5 0.01))
(cl:acos 2.5)
(cl:acos #C(2.5 -0.01))
(cl:acos #C(-2.5 0.01))
(cl:acos -2.5)
(cl:acos #C(-2.5 -0.01))
(cl:atanh #C(2.5 0.01))
(cl:atanh 2.5)
(cl:atanh #C(2.5 -0.01))
(cl:atanh #C(-2.5 0.01))
(cl:atanh -2.5)
(cl:atanh #C(-2.5 -0.01))
Submitted by Robert Dodier (robert.dodier@gmail.com)
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