Very Slow Assignment for Clas Properties

Hi

I have a class with a number of properties. One of the methods for this class which uses these properties is called many times (530,553 times) as part of a sim i run.

Problem is referencing the properties takes up too much cumulative time.

For example I have:

classdef World < handle

properties state = 0;

end

methods

 function thisWorld = World()
 end

 function act(thisWorld)
  myState = thisWorld.state; % takes 15 seconds when called 503k  end

Another method updates the state property prior to calling the act() method, the values 'state' can be assigned range from 1:1:101.

Please help end

end

Answer 1

[Daniel Shub]

This is a well known problem with MATLAB classes. Unfortunately there is not a good solution that I know of. I would suggest starting at:

http://lmgtfy.com/?q=matlab+slow+assignment+class

Answer 2

[Greg]

Thanks for the response.

It does seem very poor that such a performance hit it incurred when using classes. I'm not a professional programmer but as I see it the use of OO is particularly useful in structuring and maintaining complex code which typically would also be time consuming like sims.

As a result the OO features of the Matlab language are for me redundant.

Are there any plans from Mathworks to address this issue?

Many thanks Greg

[Daniel Shub]

It is a problem. Sometimes you can get around the problem by changing how your code works. For example:

N = 503e3;

thisWorld = World;

for ii = 1:N

myState = thisWorld.state;

end

is much faster than

for ii = 1:N

act(thisWorld);

end

obviously not all problems can be solved this way, but sometimes they can be.