On Mar 27, 2008, at 12:58 PM, Chris Godsil wrote: > > I want to extract the "real part" of a quaternion, i.e., if > > L.<i,j,k> = QuaternionAlgebra(QQ,-1,-1); > > and a is in L, then I want the coefficient of 1 in the expansion of as > a linear combination of 1, i, j and k. > > Is there a way to do this? A graceful way?
One way is: x.reduced_trace()/2 since you are working over QQ :-} Another is x.vector()[0]. Note that, if x is a Sage (or generally, python) object, "x.TAB" will get you a list of "methods" that might[*] apply to x. Then if 'foo' is one, "x.foo?" will get you documentation[+] on what 'foo' does. HTH Justin [*] Some methods are shown due to inheritance, and might actually not apply in a specific situation. [+] Documentation: the best documentation is had with "??" we might not find it in either case, if it's not in a ".py" file. -- Justin C. Walker, Curmudgeon at Large Director Institute for the Enhancement of the Director's Income ----------- Nobody knows the trouble I've been ----------- --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
