CODEWITHSUNDEEP
oopmatlablifecycle
Henning
Henning

Reputation: 163

Slow Deletion of Handle Object in MATLAB

I used MATLAB to write a simulation engine for the simulation of product flows in a production environment. I inherited all used class from handle and used these handles (quite excessively, I guess) to link between e.g. products and work systems, orders, etc.

Now, to run multiple instances of my model, I create a simulation object that contains all other objects and their relations, run the model and free the simulation variable.

Creating and running the model takes ~50 seconds (this including the generation of all objects, their relations and of course the calculation over the course of the simulation run). Freeing the variable before the next run, currently takes ~3-4 minutes!

I tried clear, delete and plain overwriting of the old simulation object, without notifying significant differences in performance.

Is there a way to improve the performance without rewriting the code?

Upvotes: 1

Views: 324

Answers (2)

jHops
jHops

Reputation: 339

Do you happen to use cell arrays to store other handle objects from within a handle object? This can cause serious slowdowns prior to Matlab R2011A. See http://www.mathworks.com/support/solutions/en/data/1-6VVMS0/index.html?product=ML

A workaround is to use a temp local variable to manipulate cell array, then assign this tmp variable back to your handle object property. I saw ~ 100X improvement in performance after doing this in one case.

Upvotes: 0

Andrey Rubshtein
Andrey Rubshtein

Reputation: 20915

It is hard to say anything particular about your code without seeing it, or at least some high level design.

A short advice before optimizing the OO aspects : Are you sure that the bottleneck is in the objects creation? Verify it with the profiler.

If the OO is indeed the bottleneck, here are some guesses:

  1. You have used circular references. Matlab does not use garbage collector, but rather a smart reference counting mechanism, which can be quite slow in this case. Change the references between the objects to be tree-like instead.

  2. You have created an enormous amount of objects. Matlab has a significant overhead for each object, much more than the traditional languages (c++, java). Re-design the system to have a smaller amount of objects.

Upvotes: 1

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