How to Compute MvPattern?

I'm trying to compute the MvPattern Sparsity Matrix S for the use in ODE15s solver because my Mass Matrix M(t,y) is strongly depending on y and the calculatin is therefore very slow. Can someone give me a quick example how to build such a matrix? I don't understand the advices in the MATLAB help! Thanks!

[Marius]

Can nobody help?

Answer 1

[Steven Lord]

Look at the list of examples on this documentation page. Find one or more examples that say they use the Mass option and whose descriptions sound sort of like the problem you're trying to solve. Read and understand what those options are doing. If after doing that you're still not clear on how to create the mass matrix, post a new question with more details about the specific problem you're trying to solve.

[Marius]

I'm still trying to calculate MvPattern. I read all the docs. The Mass matrix is not the problem. I calculated this, but I don't understand how to calculate the MvPattern.

[Marius]

I tried too figure it out, for example if i have:

M = [y2 1; y1 y1] and y = [y1; y2]

is the sparsity pattern correct as:

S = [0 0; 1 0]

or as a second example:

M = [y1 y2; y2 y1] and y = [y1; y2]

S = [0 0; 0 0]

?