[GiNaC-list] conjugates of power objects

[Burcin Erocal]

On Mon, 26 Apr 2010 18:02:40 -0700 (PDT)
kcrisman <kcrisman at gmail.com> wrote:

> On Apr 26, 4:09 pm, John Cremona <john.crem... at gmail.com> wrote:
> > This is certainly a bug:
> >
> > sage: a = sqrt(-3)
> > sage: a
> > sqrt(-3)
> > sage: a.conjugate()
> > sqrt(-3)
> >
> > sage: bool(a==a.conjugate())
> > True
> >
> 
> Yeah, this is bad, and according to a.conjugate?? it seems to be
> something wrong with our Ginac/Pynac use.

This is a bug in GiNaC:

ginsh - GiNaC Interactive Shell (ginac V1.5.7)
  __,  _______  Copyright (C) 1999-2010 Johannes Gutenberg University Mainz,
 (__) *       | Germany.  This is free software with ABSOLUTELY NO WARRANTY.
  ._) i N a C | You are welcome to redistribute it under certain conditions.
<-------------' For details type `warranty;'.

Type ?? for a list of help topics.
> sqrt(-3);
sqrt(-3)
> conjugate(sqrt(-3));
sqrt(-3)


For conjugation, power objects just compute the conjugate of the basis
and the exponent, and construct a new power object from these. Here is
the relevant function:

http://pynac.sagemath.org/hg/file/3ece9ba22005/ginac/power.cpp#l805


Cheers,
Burcin