How to set the max number of workers in parpool/matlabpool from console?

matlab parfor
Luis Felipe picture Luis Felipe · Jul 8, 2014 · Viewed 10.4k times · Source

I know how to change the maximum number of workers using the Parallel preferences window in Matlab, but I cannot find any documentation about how to make changes on the preferences from console/code, and specifically about how to change the maximum number of workers I can use in a forloop. Any help will be greatly appreciated.

Answer

Andrew picture Andrew · Jul 8, 2014

You want the parpool function. With no arguments it creates a default number of workers, with an integer argument it creates that many workers. If you just use a parfor loop without calling it, you get the default number for your profile, but I'm not sure where that is set. There's more documentation on the mathworks website: http://www.mathworks.com/help/distcomp/parpool.html

The maximum number of workers should be effectively as large as you want, but you will stop gaining any efficiency if you create more workers than you have processors. Let me know if you need any advice on picking a good number of workers.

Related questions

Matlab: Print progress from parfor loop

I run a lot of long simulations in Matlab, typically taking from a couple of minutes to a couple of hours, so to speed things up I decided to run the simulations simultaneously using a parfor loop. arglist = [arg1, arg2, …

Read More
MATLAB parfor is slower than for -- what is wrong?

the code I'm dealing with has loops like the following: bistar = zeros(numdims,numcases); parfor hh=1:nt bistar = bistar + A(:,:,hh)*data(:,:,hh+1)' ; end for small nt (10). After timing it, it is actually 100 times slower than using the regular …

Read More
MATLAB parfor slicing issue?

I have a section of code that finds Harris corners in a sequence of images. I need to do this for 92 images, but it's rather slow. As such, I'd like to run the code in parallel. The code I have …

Read More