Running functions in parallel

clc;
pause on
tic;
parpool(2);
f1 = parfeval(@Function_I, 1);
f2 = parfeval(@Function_II, 1);

function1=Function_I();
function2=Function_II();

delete(gcp('nocreate'));

function func1 = Function_I()
    
        disp('Starting function 1:');  
        startF1=toc
            a=5;
            b=6;
            func1=a*b;
            pause(0.1);
        disp('End function 1:');    
        EndF1=toc
    
end

function func2 = Function_II()
    
        disp('Starting function 2:');    
        StartF2=toc
        a=4;
        b=6;
        func2=a*b;
        pause(0.1);
        disp('End function 2:');    
        EndF2=toc
    

Command Window displays;

>>

Starting parallel pool (parpool) using the 'local' profile ...

Connected to the parallel pool (number of workers: 2).

Starting function 1:

startF1 =

15.9759

End function 1:

EndF1 =

16.0768

Starting function 2:

StartF2 =

16.0772

End function 2:

EndF2 =

16.1776

Parallel pool using the 'local' profile is shutting down.

>>

Clearly Function_I is executed before Function_II. Does anyone know how I can make these two functions run at the same time. I have tired using 'parpool' but this does not seem to work

Answer 1

[Edric Ellis]

In your code above, the two parfeval lines are initiating asynchronous function evaluation requests in parallel. You're also calling Function_I and Function_II directly in the client session on the subsequent lines, and that's what's being printed out in the command window. I suggest removing those two lines (i.e. function1=Function_I();), and instead add the following after the parfeval lines:

wait(f1); wait(f2); % Wait for parallel execution to complete
f1.Diary % Display the command-window output from the execution of Function_I
f2.Diary % ... and Function_II

You can also get the results using

result_1 = fetchOutputs(f1);
result_2 = fetchOutputs(f2);