Why does Jpattern option not improve execution time of ODE solver?

4 views (last 30 days)
Francisco de Castro
Francisco de Castro on 26 Oct 2018
Edited: Torsten on 26 Oct 2018
I have a system of ~100 ODEs. They represent interactions between species in an ecosystem. Each species interacts only with a small set of other species, so the matrix of interactions is relatively empty (~65% zeros). I'm trying to improve the speed of integration by using the option 'JPattern' in odeset, as:
options= odeset('JPattern',sparse(A))
where A is a 0 and 1 square matrix in which Aij= 1 means variables i and j interact. However, including 'JPattern' in the options actually increases execution time by a factor of 2: from 4.8 sec. to 9.7 sec. in average. It happens with at least several ODE solvers. Shouldn't the execution time reduce at least somewhat? Does the matrix A need to have some level of 'sparsiness' to improve the speed? Any ideas what am I doing wrong here?
Torsten on 26 Oct 2018
This has to be tested for each case separately. No general rule can be given.
Try a really sparse example, e.g. the discretized heat equation in one dimension.

Sign in to comment.

Answers (0)




Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!