how to know if I can use parfor

hi there, I am a telecommunication student working on some matlab code. I have a group signal to noise ratio(SNR) and need to run a loop to go through all the SNR, e.g. substituting the SNR into some code. I gave an example here

for i=1:length(SNR)

a=b(SNR(i))%some code/function need to substitute the SNR

end

Can I use the parfor to speed up? how can I justify if I can use parfor or not.

[Luca Ferro]

if this is all you needed and my answer is satisfactory could you please accept it and close the question?

Answer 1

[Luca Ferro]

to use parfor() you need either a Matlab coder software (so standalone code) or the Parallel Computing Toolbox. Other than that i know no technical conditions that could limit its use.

Basically the syntax would be:

parfor (i=1:length(SNR),c),

a=b(SNR(i))%some code/function need to substitute the SNR

end

c is the number of cores you would like to use, if less cores than what you specify are available, it will use the most amount.

note that there is no guarantee that the operations in the parfor loop will be executed in order.

I think that in most cases it is overkill to use it and it would be better to optimize the code instead if possible. So if the only reason is to have the code run in a couple less seconds or minutes, i would not use it.

[mingcheng nie]

thank you for your answer. I learned that matlab usually didn't use all the cores of CPU in conventional code, i.e., not the parallel computing. May I know why?

[Luca Ferro]

i think you can find an answer here

[Walter Roberson]

MATLAB recognizes parfor even if you do not have the toolbox. If you do not have the toolbox installed and licensed then it executes the iterations in serial in reverse order.