id	summary	reporter	owner	description	type	status	priority	milestone	component	resolution	keywords	cc	work_issues	upstream	reviewer	author	merged	dependencies	stopgaps
9881	fix the symbolic csgn function on complex input	burcin	burcin	"Our wrapper of the csgn function from GiNaC (in `sage/symbolic/expression.pyx`) doesn't reflect it's real definition:

{{{
  /** Return the complex half-plane (left or right) in which the number lies.
   *  csgn(x)==0 for x==0, csgn(x)==1 for Re(x)>0 or Re(x)=0 and Im(x)>0,
   *  csgn(x)==-1 for Re(x)<0 or Re(x)=0 and Im(x)<0.
   *  */
}}}

Fix this and add doctests.

We should also consider using GiNaC's `csgn()` function for the top level `sgn()` and `sign()` functions. This should be on a different ticket though."	defect	closed	major	sage-4.6	symbolics	fixed	pynac			N/A	Karl-Dieter Crisman	Burcin Erocal	sage-4.6.alpha3