Opened 10 years ago
Closed 10 years ago
#829 closed defect (fixed)
atanh branch cut wrong?
Reported by: | rtoy | Owned by: | rme |
---|---|---|---|
Priority: | normal | Milestone: | |
Component: | ANSI CL Compliance | Version: | trunk |
Keywords: | Cc: |
Description
In ccl 1.6 (32-bit) we have
1 > (atanh #c(-2d0 -1d-20)) #C(-0.5493061443340549D0 -1.5707963267948966D0)
but
1 > (atanh #c(-2d0 -0d0)) #C(-0.5493061443340549D0 1.5707963267948966D0)
The spec says that for on the negative real axis less than -1, atanh is continuous with Quadrant III. Since (float-sign -0d0) -> -1d0, both answers should have the same signs and the imaginary part should be negative.
Change History (3)
comment:1 Changed 10 years ago by gb
- Component changed from IDE to ANSI CL Compliance
comment:2 Changed 10 years ago by rme
- Owner set to rme
comment:3 Changed 10 years ago by rme
- Resolution set to fixed
- Status changed from new to closed
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(In [14665]) In ATANH, in the complex argument case, use the formula from the spec exactly. We were using the identity log(x/y) = log(x) - log(y), but this appears to alter the branch cut.
Fixes ticket:829.