#11423: Make atan2(0,0) consistent
-------------------------+--------------------------------------------------
Reporter: kcrisman | Owner: burcin
Type: defect | Status: new
Priority: major | Milestone: sage-4.7.1
Component: symbolics | Keywords:
Work_issues: | Upstream: N/A
Reviewer: | Author:
Merged: | Dependencies:
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Description changed by kcrisman:
Old description:
> This is bad:
>
> {{{
> sage: atan2(0,0)
> 0
> sage: atan2(0,0,hold=True)
> arctan2(0, 0)
> sage: atan2(0,0,hold=True).n()
> ValueError: arctan2(0,0) undefined
> sage: atan2(0,0,hold=True).simplify()
> -----------------------------------------------------
> TypeError: Error executing code in Maxima
> CODE:
> sage1 : atan2(0,0)$
> Maxima ERROR:
>
> atan2: atan2(0,0) is undefined.
> -- an error. To debug this try: debugmode(true);
> }}}
>
> Probably we should make sure that atan2(0,0) always raises an error.
> Wolfram Alpha/Mathematica gives the interval from -pi to pi, which seems
> as good as any answer, and who knows what others do.
>
> Originally reported at
> [http://ask.sagemath.org/question/578/atan2-bug|ask.sagemath.org].
New description:
This is bad:
{{{
sage: atan2(0,0)
0
sage: atan2(0,0,hold=True)
arctan2(0, 0)
sage: atan2(0,0,hold=True).n()
ValueError: arctan2(0,0) undefined
sage: atan2(0,0,hold=True).simplify()
-----------------------------------------------------
TypeError: Error executing code in Maxima
CODE:
sage1 : atan2(0,0)$
Maxima ERROR:
atan2: atan2(0,0) is undefined.
-- an error. To debug this try: debugmode(true);
}}}
Probably we should make sure that atan2(0,0) always raises an error.
Wolfram Alpha/Mathematica gives the interval from -pi to pi, which seems
as good as any answer, and who knows what others do.
Originally reported at [http://ask.sagemath.org/question/578/atan2-bug
ask.sagemath.org].
--
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11423#comment:1>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
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