Why do my parfor loops run in parallel in matlab interactive mode, but in serial mode when I deployed, using Matlab compiler?

I have multiple programs that contain parfor loops. These parfor loops successfully execute the relevants sections in parallel when I run in interactive Matolab.

However when I deploy these programs using Matlab compiler, they only run in serial. It seems the Matlab compiler is not honouring my setting "Automatically create a parallel pool (if one doesn't exist) when parallel keywords are executed", which I have enabled in my Matlab settings. (I am compiling using the same settings, so these settings should be baked into the deployed app).

[Matt J]

I am compiling using the same settings, so these settings should be baked into the deployed app

I have a feeling that might not be a valid expectation. I don't see any such setting in the run-time options within the deploytool.

[William Smith]

I'm compiling using mcc. I believe that the deployed program contains $PREFDIR and its contents, and unpacks these into $TEMPDIR/mcrCache9.1/ at runtime. I can see "parallel.settings" in that folder. And I can see

 <key name="AutoCreate">
                <bool>
                    <value>1</value>
                </bool>
 </key>

within that file.

Answer 1

[William Smith]

Note, after 1 day messing around, I was able to work around this by explicitly calling parpool() just before my parfor. This should not be necessary because of the "Automatically create a parallel pool" settings.

Note, I am running Matlab 2016b. I have not verified this incorrect behaviour on a more recent version of Matlab.