how to disable matlabpool/parpool

i recently upgraded to matlab2018 from an older version. previously, parfor ran in serial unless a worker pool was opened explicitly. now in the newer version, the pool seems to open when parfor is detected.

how can i disable this behavior? -- i want to call 'parfor' but have it run in serial unless i explicitly open the pool.

Answer 1

[Walter Roberson]

https://www.mathworks.com/matlabcentral/answers/112457-controlling-new-parallel-feature-automatically-create-a-parallel-pool-when-parallel-keywords-are-ex

Change the Autocreate preference.

[kkyaj]

"

1.) Turn off auto-opening pools in the parallel preferences UI. Then you have essentially the same situation as existed in R2013a.

2.) Use the optional "number of workers" argument in your PARFOR loop - see the documentation for more.

"

Option 1 requires opening the GUI, which i don't have access to via remote sessions.

Option 2 requires modifying multiple scripts. It is more desirable to maintain a single copy of the code for use on multiple ML releases.

Neither of these is satisfactory in my case. Is there a script/command-line method of applying #1?

[Walter Roberson]

There is no provided command line method.

Fredrick showed which part of which file has to be changed. You can use any method to change that, including sed

https://www.mathworks.com/matlabcentral/answers/112457-controlling-new-parallel-feature-automatically-create-a-parallel-pool-when-parallel-keywords-are-ex#comment_189892

[kkyaj]

i dislike it, but i'll accept your (Friedrich's) solution for the sake of moving on. the solution was a work-around from 2014. i am somewhat surprised that no local per-instance behaviour setting can be supplied after almost 5years.

my sysadmin will need to make changes on some systems that use system-wide prefs.

[Walter Roberson]

I do not know if anyone ever put in an enhancement request for this. I know that I did not put in a request for it, as it is a not a bug, and I did not have a use for it myself, and I have seen very few requests for it.