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.Fri, 22 Nov 2013 19:45:41 -0600Large symbolic determinanthttps://ask.sagemath.org/question/8021/large-symbolic-determinant/I have a dense matrix with symbolic variable entries. I am interested in the equation that describes when the matrix is singular. So I have been having Sage compute the determinant of this matrix and set it equal to zero, and return this expression (a polynomial in several variables).
However when the dimensions get larger (around 9 variables) Sage is taking an incredibly long amount of time to do it. (My program has to perform a number of other tasks as well, the determinant seems to be taking up all the run-time.)
Is there any way I can speed up this kind of computation?David FerroneThu, 24 Mar 2011 17:06:25 -0500https://ask.sagemath.org/question/8021/Determinant of block matriceshttps://ask.sagemath.org/question/10766/determinant-of-block-matrices/I need to calculate the determinant of a symbolic 4x4 matrix M, where each cell itself is a matrix itself.
Is that possible?
I did a beginner's check, and it did not seem to work:
mq=matrix(SR, 2, 2, 'a b c d'.split(' '))
MQ=matrix(SR, 2, 2, [mq, mq, mq, mq])
MQ.det()
Traceback (click to the left of this block for traceback)
...
TypeError: mutable matrices are unhashable
kautschukFri, 22 Nov 2013 19:45:41 -0600https://ask.sagemath.org/question/10766/