Hello.
Indeed, I just want to define complex number via the algebraic form z=a+i*b.
expr.simplify_real() will be a great tool. I will be patient...
*Christophe BAL*
*Enseignant de mathématiques en Lycée **et développeur Python amateur*
*---*
*French math teacher in a "Lycée" **and **Python **amateur developer*
2015-01-29 23:50 GMT+01:00 Michael Orlitzky <mich...@orlitzky.com>:
> On 01/28/2015 03:56 PM, Christophe Bal wrote:
> > Hello.
> >
> > How can I define a symbolic variable that is a real number ? Therer is an
> > optional argument real in the latest versions of Sympy but this not work
> in
> > Sage.
> >
>
> There isn't much support for declaring a variable real in Sage. By
> default every variable is complex, but there are some operations that
> will treat them as real.
>
> We have three ways to "declare" a variable real but they're all weird:
>
> * assume(x, 'real')
> * x = SR.var('x', domain='real')
> * Set the maxima simplification domain to real through some backdoor
>
> I don't know what (if anything) the second one does. The first allows
> Maxima to make some simplifications it otherwise couldn't. The third
> lets sqrt(x^2) be equal to abs(x) but there's no easy way to do it. And
> even though #1 and #3 both use Maxima, #3 doesn't imply #1.
>
> In the next release you'll be able to do expr.simplify_real() and have
> it do #1 #2 and #3 all at once along with simplify_log().
>
> So really what we need to know is, why do you want to declare a real
> variable? You might be better served by a polynomial ring or some linear
> algebra thing.
>
> --
> You received this message because you are subscribed to the Google Groups
> "sage-support" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to sage-support+unsubscr...@googlegroups.com.
> To post to this group, send email to sage-support@googlegroups.com.
> Visit this group at http://groups.google.com/group/sage-support.
> For more options, visit https://groups.google.com/d/optout.
>
--
You received this message because you are subscribed to the Google Groups
"sage-support" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to sage-support+unsubscr...@googlegroups.com.
To post to this group, send email to sage-support@googlegroups.com.
Visit this group at http://groups.google.com/group/sage-support.
For more options, visit https://groups.google.com/d/optout.
