Graceful exit from a parfor loop

If I detect an error while processing data within a parfor loop, I would like to gracefully exit the program. Can I delete the parallel pool object using "delete" to shut down all of the workers before exiting?

Answer 1

[Matt J]

It sounds like a job for onCleanup.

[Clay Fulcher]

Thanks Matt. I'll give this a try. I'm not sure it will destroy all the independent workers in a parallel loop, but I'll give it a try. Do you know if simply deleting the parallel pool object will accomplish the destruction of the tasks being performed by all the independent workers in the parfor loop?

[Matt J]

Do you know if simply deleting the parallel pool object will accomplish the destruction of the tasks being performed by all the independent workers in the parfor loop?

A simple error will do that. If even one of the workers hits an error, the whole loop aborts and all of the workers stop what they are doing. The only question at that point is whether you want the pool left open. So your code could look like this:

function output=runSomething(poolSize)

  objPool = parpool(poolSize);

  objCleanup=onCleanup( @() delete(objPool));

  try
      parfor i=1:N
          
          
      end
      output=...
  catch
       disp 'The loop failed. Aborting'
       output=[];
       return
  end
  
 

end

This will completely close the pool whether the function runs to successful completion or not.