Interrupt a while loop with functions if it takes too long

I have a while loop containing several functions. If one of these functions takes to long, I want to break it.

All solutions that I found do not work because they check the time not continuely during the execution, but at the end of the functions.

Is there a way of timing the iteration during its execution and break it?

I mean with code, not ctrl-c

[Aquatris]

you can also use a timer to check the execution time and provide warning. I am not sure how you would stop execution of a function within a while loop from timer callback. Maybe another global flag can be used. This community loves global variables (!)

global tStart tMax % global variables so they can be reached from timer callback function

tMax = 4; % seconds

% create timer
t = timer;
t.StartDelay = 1;
t.Period = 2;
t.ExecutionMode = 'fixedRate';
t.TimerFcn = @stopExec;
start(t)

cnt = 0;
% dummy while loop
while cnt >=1
   tStart = tic;
   myFun1;
   tStart = tic;
   myFun2;
   tStart = tic;
   myFun3;
   cnt = cnt+1;   
end

% timer function that gives error
function stopExec(~,~)
global tStart tMax
if isempty(tStart)
   tStart = tic;
end

% create warning when time limit it exceeded
funCallStack = dbstack; % get running function stack
if toc(tStart)>=tMax
   warning(sprintf('Exceeded Time Limit! @ %s. \n Time limit: %.2f,Current Execution Time: %.2f ',funCallStack(4).name,tMax,(toc(tStart))))
end
end

% dummy functions called from while loop
function myFun1()
pause(5)
end
function myFun2()
pause(8)
end
function myFun3()
pause(3)
end

Answer 1

[Torsten]

Is there a way of timing the iteration during its execution and break it?

No. You could go into the function and time certain operations therein. But you always have to wait until the operations are done before getting the chance to stop the code.

[darwusch darwusch]

thanks

[Torsten]

Exiting a while loop is usually done by counting the number of times it is executed and exiting if a prescribed maximum number of loops is reached:

nmax = 10;
count = 0;
i = 1;
while count < nmax
    i = 2*i;
    count = count + 1;
end
i

i = 1024

[darwusch darwusch]

No that does not break the iteration during its execution, but after it already finished. That's too late.

Answer 2

[jwiix]

function [outputArg1,outputArg2] = yourFunction()
    %YOURFUNCTION Summary of this function goes here
    %   Detailed explanation goes here
    outputArg1 = 1;
    outputArg2 = 2;
end
function [outputArg1,outputArg2] = yourFunction2()
    %YOURFUNCTION Summary of this function goes here
    %   Detailed explanation goes here
    outputArg1 = 1;
    outputArg2 = 2;
    wait(10);
end
function result = runWithTimeoutSimplified(func, timeout)
    % Create a parallel pool if it doesn't exist
    if isempty(gcp('nocreate'))
        parpool('local', 1);
    end
    % Start the function asynchronously
    f = parfeval(@() func(), 1);
    tic;
    a=true;
    runFlag=0;
    while a
        b=toc;
        a=b<timeout;
        % Wait for the function to complete or timeout
        if strcmpi(f.State,'running')
            runFlag =1;
        else
            runFlag=0;
            [result] = fetchOutputs(f);
            break;
        end
    end
    if runFlag 
        cancel(f);
        disp('Operation cancelled due to timeout')
    else
        disp(result);
    end
end
% Then in console:
>> result = runWithTimeoutSimplified(@yourFunction, 5) % This should pass and display result
>> result = runWithTimeoutSimplified(@yourFunction2, 5) % This will fail and be cancelled after timeout .. in this case 5 seconds