Array performance in class attributs

Question

Franck AUBINEAU 2024-2-5

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2078211-array-performance-in-class-attributs

评论： Franck AUBINEAU 2024-2-5

采纳的回答： Shivam

Here is an (short) example of the observed problem. It is not the exact code but it is the exact problem :-)

% Class

classdef MaClasse < handle

properties (Access = public)

tabVal = [];

end

% Code, declaration, allocation

pTest = MaClasse();

pTest.tabVal = zeros(200,1000);

tmp = zeros(200,1000);

% Problem

pTest.tabVal(10,:) = ones(1,1000); %

tmp(10,:) = ones(1,1000); % -> twice even more faster than the line above

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Answer 1

Shivam 2024-2-5

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https://ww2.mathworks.cn/matlabcentral/answers/2078211-array-performance-in-class-attributs#answer_1402841

Hi Franck,

Based on the code you have shared, it seems you want to know the discrepancy in execution time between assigning a matrix of ones to a property of a custom class object and assigning it directly to a standard array.

It is important to know that the observed difference in performance comes from MATLAB's additional processing when dealing with class properties. Whenever you alter a property of a handle class, MATLAB has to conduct extra operations, including managing object references and maintaining the integrity and encapsulation of the data.

And, with a conventional matrix such as tmp, MATLAB can interact with and alter the memory directly, bypassing the complexities introduced by object-oriented features.

I hope it helps in understanding the performance difference between the two lines.

Thanks

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Franck AUBINEAU 2024-2-5

Hi and thanks for this answer.

It's exactly what I think but I'm very disapointed by such a difference. I'm using Matlab class in my simulation code and it seems that performance (this example and others like access time in handle cell array) are very slow.

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