big differences in saving variables

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Abolfazl Nejatian
Abolfazl Nejatian on 24 Sep 2020
Commented: Mario Malic on 26 Sep 2020
Hi,
i need to save some tables and variables as Mat and CSV files.
but I have faced a strange behavior on saving the files.
when I save my file and evaluate the time of each of them individually, the saving time much less than I evaluate total saving time.
I also should mention the true elapsed time is a bigger time.
here are my code and output,
folderAddress = 'D:\Nejatian\';
tic
delete([folderAddress 'signals.csv'])
delete([folderAddress 'LatestSignals.csv'])
t1 = toc;
tic
writetable(T,[folderAddress 'signals.csv']);
t2 = toc;
tic
writetable(lT,[folderAddress 'LatestSignals.csv'])
t3 = toc;
tic
save([folderAddress 'visualData'],'visualData')
t4 = toc;
tic
delete('workspace.mat')
save('workspace.mat');
t5 = toc;
str1 = string(['Deleting CSV files = ' num2str(t1) 'Sec']);
str2 = string(['Writing CSV file one = ' num2str(t2) 'Sec']);
str3 = string(['Writing CSV file one = ' num2str(t3) 'Sec']);
str4 = string(['Saving Mat file from a struct variable = ' num2str(t1) 'Sec']);
str5 = string(['Saving all workspace variables = ' num2str(t1) 'Sec']);
disp([str1;str2;str3;str4;str5]);
  • Deleting CSV files = 0.0320444Sec
  • Writing CSV file one = 1.99078Sec
  • Writing CSV file one = 0.273289Sec
  • Saving Mat file from a struct variable = 0.0120444Sec
  • Saving all workspace variables = 0.00220444Sec
and the total time is
tic
folderAddress = 'D:\Nejatian\';
delete([folderAddress 'signals.csv'])
delete([folderAddress 'LatestSignals.csv'])
writetable(T,[folderAddress 'signals.csv']);
writetable(lT,[folderAddress 'LatestSignals.csv'])
save([folderAddress 'visualData'],'visualData')
delete('workspace.mat')
save('workspace.mat');
t=toc;
str = string(['Total time = ' num2str(t) 'Sec']);
disp(str);
  • Total time = 78.3331Sec
why this big difference happens and how i can speed up my File saving time?
i mean is there any way to parallelize or decompressed the output for reducing the saving file?
  5 Comments
Abolfazl Nejatian
Abolfazl Nejatian on 26 Sep 2020
Dear Mario,
yep im agree with you.
Delete function should use for CSV or text files
this line of code can be omitted.
Mario Malic
Mario Malic on 26 Sep 2020
There's an option -nocompression, but I don't know if it would make things different.

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