Parallel pool goes idle instantly in parallel GA

Hello,

I am working on a project, where a fitness function of GA executes a bash script, part of which is a OpenFOAM simulation run. (on Linux, Ubuntu 20.04). Below is the fragment of code where the GA is being launched:

    options = optimoptions('ga', 'UseParallel', true, 'UseVectorized', false ,'MaxGenerations', 500, 'MaxStallGenerations', 500, 'Display', 'iter', 'CreationFcn', @initialValidPopulation);

    ga_values = ga(@calculate_case, ...
        2*n, [], [], [], [], zeros(2*n, 1), 0.5*ones(2*n, 1), ...
        [], options); 

The MATLAB recognizes UseParallel flag and starts the pool automatically, the bottom left corner icon goes green for a few seconds and then goes blue signalizing it's idle. Also only one fitness function is executed. The same happens if I create a parallel pool manually.

What could be a source of this behavior?

[Matt J]

Describe your system.

[Rafal Szulejko]

What do you mean? It's a fresh installation of Ubuntu 20.04 with R2021b, If I remember correctly, literally the only apps installed in the system are git, Matlab, matlab-support, default-jdk and OpenFOAM v8. Hardware-wise it's a Ryzen 3900X with 32 GB of RAM.

Answer 1

[Matt J]

It sounds like you'll need to send your code to tech support in a bug report..

As a temporary workaround, set UseVectorized to true, instead. Then, use a parfor loop within your fitness function to process each row of the population matrix.

[Rafal Szulejko]

Will do that, thanks for the answer.

[Matt J]

You are welcome, but if the answer works for you, please consider Accept-clicking it.

[Rafal Szulejko]

I quickly refactored my code to use your workaround and while a bit dirty, it is working. Thank you.