ASKSAGE: Sage Q&A Forum - Latest question feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Tue, 19 Aug 2014 11:18:57 -0500Newbie question: introducing symbols (variables) inside vectors and matriceshttps://ask.sagemath.org/question/23833/newbie-question-introducing-symbols-variables-inside-vectors-and-matrices/Hi,
I would like to have linear algebra operations to be evaluated with symbols instead of numerically.
For example, having the following matrix:
A = matrix(QQ,[
[2,1,2,-6],
[-1,2,1,7],
[3,-1,-3,-1],
[1,5,6,0],
[2,2,1,1]
])
I would like to multiply for a vector with symbolic variables as follows:
t = 'real'
var('x1')
assume(x1,t)
var('x2')
assume(x2,t)
var('x3')
assume(x3,t)
var('x4')
assume(x4,t)
xx = vector(QQ,[x1,x2,x3,x4])
A * xx.transpose()
Unfortunately building the `xx` vector is unsuccessful, producing this error message:
TypeError: Cannot evaluate symbolic expression to a numeric value.
This does not work, so how can I use symbols in sage's linear algebra framework?
thank you very much,
-FrancescostablumTue, 19 Aug 2014 11:18:57 -0500https://ask.sagemath.org/question/23833/