Slow array of structure updating in saving variables in app designer

I am working on developing an application in app designer for doing a bunch of fits and saving the results in an array of structures, where each structure has various types of fields about the fit results. When I save the file, I update the array with the fit_info structure each fit, and append to the array of structures for each save step. I eventually will be doing 89x13 fits. But, each cycle gets slower and slower, so it is impractically slow by about 30 fits. I looked into saving a separate variable for each fit, by dynamically naming the variables, i.e., fit_info_1_1, fit_info_1_2, etc., but I know this is bad programming practice. Does anyone have any suggestions?

function SaveFitButtonPushed(app, event)

data_source=string(app.TextArea.Value);

filename=strcat("fit_results_",data_source);

if isfile(filename)

matObj=matfile(filename,'Writable',true);

matObj.fit_info_a(app.ColumnEditField.Value,app.CompoundEditField.Value)=app.fit_info_1;

else

fit_info_a(app.ColumnEditField.Value,app.CompoundEditField.Value)=app.fit_info_1;

save (filename,'fit_info_a','-v7.3');

end

if ~isempty(app.fit_info_2.pm95)

data_source=string(app.TextArea.Value);

filename=strcat("fit_results_2_",data_source);

if isfile(filename)

matObj=matfile(filename,'Writable',true);

matObj.fit_info_b(app.ColumnEditField.Value,app.CompoundEditField.Value)=app.fit_info_2;

else

fit_info_b(app.ColumnEditField.Value,app.CompoundEditField.Value)=app.fit_info_2;

save (filename,'fit_info_b','-v7.3');

end

end

app.k_refS_1refS_2refTextArea.Value='';

app.s_ETextArea.Value='';

app.k_refS_1refS_2refTextArea_2.Value='';

app.s_ETextArea_2.Value='';

app.phi_refEditField.Value=30;

app.phi_refEditField_2.Value=30;

str='[]';

app.OmitPointsEditField.Value=str;

app.OmitPointsEditField_2.Value=str;

end

Answer 1

[Aditya]

Hi Sarah,

Here are some suggestions that you can try to improve the performance:

1) Preallocate the Structure Array: Preallocate 'fit_info_a' and 'fit_info_b' arrays using 'repmat(struct(), 89, 13)' to avoid dynamic resizing.

2) Use 'matfile' Efficiently: Open the MAT-file once and update the specific elements directly.

Here is the sample code based on the above suggestion:

% Check if the file exists and create or load it accordingly
    if isfile(filename)
        matObj = matfile(filename, 'Writable', true);
    else
        fit_info_a = repmat(struct(), 89, 13); % Preallocate for 89x13 fits
        save(filename, 'fit_info_a', '-v7.3');
        matObj = matfile(filename, 'Writable', true);
    end
    
    % Update the specific element in the preallocated structure array
    matObj.fit_info_a(app.ColumnEditField.Value, app.CompoundEditField.Value) = app.fit_info_1;

similarly, you can modify the other section of the code.

By preallocating the array and using the 'matfile' object, you avoid the overhead of dynamically resizing the array and loading/saving the entire file repeatedly. This should improve the performance of your application.

I hope the above suggestions will help you improve the performance!