Thanks a lot Mike. Defining a variable as a member of a particular field such as RR is exactly what I have been wanting to do and I did not really undersand how to do it until I saw your domain=RR example.
On Feb 17, 11:13 pm, Mike Hansen <[email protected]> wrote: > On Thu, Feb 17, 2011 at 1:30 PM, Jeff <[email protected]> wrote: > > To be consistent with the assumption, though, I think that iimag(a) > > should return zero. > > > Can anyone comment? > > Unfortunately, the assumptions system (still) is not well integrated > with the Pynac code. When you do assume(a, 'real'), it sends that > assumption to Maxima, and Sage/Pynac does not really know anything > about it. In order for it to be "in effect", you have to send the > expression to Maxima and ask it to simplify it: > > sage: var('a') > a > sage: assume(a, 'real') > sage: imag(a) > imag_part(a) > sage: imag(a).simplify() > 0 > > Additionally, you can specify the "domain" (complex, real, positive) > of a variable within Pynac directly by doing > > sage: a = var('a', domain=RR) > sage: imag(a) > 0 > > However, this does not create the corresponding assumption within Maxima. > > --Mike -- To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
