Matlab script is very very slow! Help me please!

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Rocco De Luca 2019-12-26

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评论： Rocco De Luca 2019-12-29

HelpMe.txt

Hello! I am a student and I created a Matlab code that allows me to open many txt files in succession and perform these sums and other operations. The work that the code has to do is a lot but it is really too slow. I calculated that it would take two days to finish. I think there is some conflict. Please ask me to help me otherwise I will have to do all those operations by hand and it will be a disaster for me. Thanks to those who will help me

I enclose the code I wrote in a text file

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Rocco De Luca 2019-12-26

You're absolutely right, sorry. I put a mega link where you can download the files. I can't attach them here because they are more than 7 mega and it doesn't accept rar files. Thanks so much.

https://mega.nz/#F!DlsCnAoL!H4kt4t5QX-5-ACj8rr09Tw

Rocco De Luca 2019-12-26

These are hourly powers related to a simulated hybrid system.

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Answer 1

per isakson 2019-12-26

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编辑：per isakson 2019-12-26

在 MATLAB Online 中打开

Why not just let it run over a weekend?

See Techniques to Improve Performance and Profile to Improve Performance

I've downloaded your files and invoked your script. I interrupted the execution during the fourth data file. The script consists of three nested loops. One statement in the innermost loop uses 90% of the execution time.

for ii = 1 : 512
    ...
    for kk = 1 : 8760 % What about leap years? 
        ...
        for jj = 1 : 8760 % What about leap years? 
            R(ii,[1:5,8:27])=R(ii,[1:5,8:27])+intermedia(jj,[1:5,8,9,11:21,29:35]); % 90%
            ...
        end
    end
end

The innermost loop does a number of summations. Replacing the innermost loop by

R(ii,[1:5,8:27]) = sum( intermedia(1:8760,[1:5,8,9,11:21,29:35]), 1 );
is_positive = intermedia(1:8760,7)>0;
R(ii,6) = sum( intermedia(is_positive,7) );
R(ii,7) = sum( intermedia(not(is_positive),7) );

improves the speed of the script significantly. (You need to confirm that it returns the correct result.)

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per isakson 2019-12-26

Did you try the profiler?

I don't think there are more low hanging fruits.

Rocco De Luca 2019-12-26

编辑：Rocco De Luca 2019-12-26

Yes, I used the profiler. I attach the profiler and the code that I used since I slightly modified it.

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Answer 2

Rocco De Luca 2019-12-27

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Cod.txt

Hello and sorry if I still disturb you. To speed up even more I thought of replacing the second for with a method similar to the one you used. I am attaching the code, what do you think?

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per isakson 2019-12-27

Assume that your original code with the three loops produce the expected result. Use that result as a reference. Each new version shall produce exactly (a floating point error is ok) the same result. That can be tested systematically with the Unit Testing Framework. If the results are identical and if there is enough variation in the data files, COMPLETOA20KM*, the new code is most likely correct. Are the results identical?

Rocco De Luca 2019-12-29