ASKSAGE: Sage Q&A Forum - Latest question feedhttp://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Thu, 14 Jun 2012 10:58:48 -0500Substitution using Dictionary with Matrix as Valuehttp://ask.sagemath.org/question/9075/substitution-using-dictionary-with-matrix-as-value/As a newcomer to SAGE, trying to use it to do symbolic linear algebra, I am wondering why substitution of a variable using a dictionary doesn't work in this case:
sage: aMatrix = matrix(SR,1,1)
sage: var('aVariable')
aVariable
sage: aDict = {}
sage: aDict[aVariable] = aMatrix
sage: aDict[aVariable]
[0]
but:
sage: aVariable.subs(aDict)
....
/Applications/sage/local/lib/python2.7/site-packages/sage/symbolic/expression.so in sage.symbolic.expression.Expression.substitute (sage/symbolic/expression.cpp:16025)()
/Applications/sage/local/lib/python2.7/site-packages/sage/symbolic/expression.so in sage.symbolic.expression.Expression.coerce_in (sage/symbolic/expression.cpp:11265)()
/Applications/sage/local/lib/python2.7/site-packages/sage/structure/parent_old.so in sage.structure.parent_old.Parent._coerce_ (sage/structure/parent_old.c:3369)()
/Applications/sage/local/lib/python2.7/site-packages/sage/structure/parent.so in sage.structure.parent.Parent.coerce (sage/structure/parent.c:8912)()
TypeError: no canonical coercion from Full MatrixSpace of 1 by 1 dense matrices over Symbolic Ring to Symbolic Ring
Functionality to substitute matrices for variables seems to be indispensable to doing symbolic linear algebra, so I am sure there is a proper way to do this.
heatkernelThu, 14 Jun 2012 10:58:48 -0500http://ask.sagemath.org/question/9075/