Parallel processes in MATLAB App Designer

I am doing an app, which has a loop that is being performed each 10 seconds (it is an infinite loop with a flag to exit and has a 10 sec pause). Also, in the app I have a button which callback starts another matlab script. While the script is running, it is writing its "progress" to the .txt file (this is just a float type number).

The idea is that while the script is running, the app reads this number each 10 seconds from the .txt file and shows it in an edit field box. However, while the app is running, as I push the button which starts the matlab script, no changes in Edit Field appear, even though the numbers in the .txt file change. As soon as the matlab script finishes, Edit field shows 100% (the latest number). It seems like App Designer performs the whole matlab script first, while holding the loop on a pause, and starts it again only after the script is finished.

On some different websites I read that those processes should go in parallel (without any additional toolboxes). Is that right? What should I do in order to make Edit Field update "online" with the script processing?

I know that there is a command "drawnow", but I do not know, where to put it, since the loop is being frozen. Relevant parts of the code are below:

This is a loop:

function imaging(app)

progres_path = strcat(app.Directory,'/progres.txt'); %reaching for the .txt file

progres = fopen(progres_path, 'r'); %opening for reading

while ~(app.ExitLoopFlag) %exit loop flag (true before the app is being closed)

if isfile(strcat(app.Directory,'/New_Net/VGG_new_results.mat'))

load(strcat(app.Directory,'/New_Net/VGG_new_results.mat'),'FPR', 'TPR','AUC', 'val_accuracy', 'sensitivity', 'specificity');

cla(app.UIAxes,'reset');

app.UIAxes.GridAlpha = 1;

plot(app.UIAxes,FPR,TPR,'Color','r','LineWidth',2);

leg = strcat('AUC = ', num2str(AUC));

legend(app.UIAxes, leg);

xlabel(app.UIAxes,'False positive rate');

ylabel(app.UIAxes,'True positive rate');

title(app.UIAxes,'ROC Curve');

app.ExitLoopFlag = true;

app.AdddirectoriesButton.Enable = 'on';

app.RetrainthenetButton.Enable = 'on';

end

pause(10); %waiting for 10 seconds for the next loop iteration

percentage = fscanf(progres, '%s'); %reading data from file

result = strcat(percentage, ' %'); %forming a string

app.ProgresspreprocessingEditField.Value = result;

drawnow; %trying to push the changes (doesn't work)

end

fclose(progres); %closing the file

app.ProgresspreprocessingEditField.Value = 'Done!';

progres = fopen(progres_path, 'w');

fprintf(progres,'%s', '0');

fclose(progres);

percentage = '0.0';

progres = fopen(progres_path, 'r');

while str2double(percentage) < 99.99

percentage = fscanf(progres,'%s');

result = strcat(percentage, ' %');

app.ProgresstrainingEditField.Value = result;

drawnow;

end

fclose(progres);

app.ProgresstrainingEditField.Value = 'Done!';

end

This is the callback:

function RetrainthenetButtonPushed(app, event)

% Disable Plot Options button while dialog is open

app.RetrainthenetButton.Enable = 'off';

app.AdddirectoriesButton.Enable = 'off';

%starting preprocessing

preprocessing = strcat(app.Directory,'/preprocessing_ML_v3.m'); %matlab script

eval(['run(''' preprocessing ''');']); %starting the matlab script

end

Answer 1

[Julian]

As I see so far:

You open the file before your loop.

So you see a value, save this value and look everytime at the old value you have stored.

You have to open the file in your loop.

[Anna]

I moved open() and close() parts inside the loop, but it didn't help. Though, I was initially reading the value inside the loop, so it should have been updated anyway, right?