Where can I find expmdemo matlab files?

Question

K 2013-4-29

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/74014-where-can-i-find-expmdemo-matlab-files

Hi,

I have a nasty symbolic matrix that I need the matrix exponential of- looks something like this (all capital letters are constants and s is a symbol that will be solved for later):

[0,1,0,0;0,0,1,0;0,0,0,1;-C*s^2,-D*s,F*s^2-G,s^2+s]

I need to take the determinant of the matrix exponential of this expression and set it equal to 0 to solve for s. Expm works fine when a few of the constants are zero, but once the entire bottom row of the matrix is populated, it is really slow and I would like to try a numerical approximation. I found references to expmdemo1.m , expmdemo2.m and expmdemo3.m on matlab help/documentation pages and would like to try these algorithms- does anyone know where I can find them??? Thank you!