On Apr 26, 9:16 pm, Burcin Erocal <bur...@erocal.org> wrote:
> On Mon, 26 Apr 2010 18:02:40 -0700 (PDT)
>
>
>
>
>
> kcrisman <kcris...@gmail.com> wrote:
> > On Apr 26, 4:09 pm, John Cremona <john.crem...@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
>
Great, thanks for this. I am changing the ticket to "not yet reported
upstream". Can you report it? Of course, if you have a quick fix,
that would be great too :) but I assume it would take a little more
thought to transform it from something that might work for a multi-
valued function to something that works for our "default" choice of
sqrt(-3) as \sqrt{3}*I.
- kcrisman
--
To post to this group, send an email to sage-devel@googlegroups.com
To unsubscribe from this group, send an email to
sage-devel+unsubscr...@googlegroups.com
For more options, visit this group at http://groups.google.com/group/sage-devel
URL: http://www.sagemath.org
