atan2(-pi,0) throws "divide by zero"

[burcin]

From sage-devel:

the summary is:
-------------------
atan2(3,0)   --> 1/2*pi
atan2(-3,0)  --> -1/2*pi
atan2(pi,0)  --> 1/2*pi
atan2(-pi,0) -->  RuntimeError: power::eval(): division by zero
--------------------

sage-devel thread is here:

http://groups.google.com/group/sage-devel/t/317e6bfe11fabb4

also reported on sage-support:

http://groups.google.com/group/sage-support/t/02f3446e68381346

Component: symbolics

Keywords: pynac

Author: Burcin Erocal, Richard Kreckel, Jens Vollinga

Reviewer: Robert Mařík

Merged: sage-4.4.1.alpha2

Issue created by migration from https://trac.sagemath.org/ticket/8565

[burcin]

add doctests

[burcin]

Author: Burcin Erocal, Richard Kreckel, Jens Vollinga

[burcin]

comment:1

Attachment: trac_8565-neg_pi.patch.gz

The pynac package at #8644 includes the patches that were merged in GiNaC to fix this problem. attachment: trac_8565-neg_pi.patch adds doctests for the fix.

This ticket now depends on #8644.

[robert-marik]

comment:2

Installs fine, all tests passed, works ad advertised. Positive review and thanks for fixing.

[robert-marik]

Reviewer: Robert Mařík

[williamstein]

Merged: 4.4.1.alpha2

[sagetrac-mvngu]

Changed merged from 4.4.1.alpha2 to sage-4.4.1.alpha2