Hi Alan, unfortunately `RunTask` in GAP is more or less only a wrapper for `CallFuncListWrap` and is indeed blocking. `RunTask` in GAP only is a mock-up of the proper `RunTask` function from HPC-GAP. HPC-GAP didn't make it out of alpha stage though and if I'm not mistaken nobody is working on it ATM.
I'm not sure whether that's the best option as I have never used it, but in principle you should be able to do parallel computations by spawning several GAP processes via the SCSCP package, see chapter 8 "Parallel computing with SCSCP" of the SCSCP manual. So I guess as long as your computations don't need a lot of memory that should be fine. Hope this helps! :-) Best, Sergio On 18.05.21 07:35, Alan Hylton wrote: > Howdy, > > Suppose I have a list of lists, and I wish to run some time-consuming > process on each of these sub-list (each sub-list is independent, so I am > not worried about race conditions). > > I think the easiest way to demonstrate my thought process is with code: > > I have a list of lists and the number of cores I wish to use - > master_list := [ [...], [...], ..., [...]]; > n := Length(master_list); > cores:=15; > > I have a time consuming function whose arguments are ranges into > master_list - > time_consuming_func := function(start_index, stop_index) > ... > end; > > I portion out master_list, creating a list a tasks - > task_list:=[]; > start:=1; > for i in [1..cores] do > flag:=0; > if i <= n mod cores then > flag:=1; > fi; > if i > n then > break; > fi; > len:=Int(n/cores)+flag; > > Add(task_list, RunTask( time_consuming_func , start, start+len-1)); > > start:=start+len; > od; > > I had several hopes: > 1: I could get a list of tasks, and then use something like TaskFinished to > see if each are done > 2: Store the result of each time_consuming_func in the global master_list > > But I ran into one problem: RunTask seems to be blocking. Instead of > spawning a process and continuing with my loop, it waits until each task > finishes. I considered DelayTask instead of RunTask so that I could just > use WaitTask, but DelayTask does not seem to exist (similarly for > asynchronous tasks). Is there an alternative? To follow the documentation, > I'd like to avoid the lower-level CreateThread if I can. > > Also, number 2 makes some assumptions on how memory works. Is it actually > valid to have a thread working on element i of master_list modify the > global master_list[i]? > > I'd greatly appreciate any insight! > > Thanks, > Alan > _______________________________________________ > Forum mailing list > Forum@gap-system.org > https://mail.gap-system.org/mailman/listinfo/forum > _______________________________________________ Forum mailing list Forum@gap-system.org https://mail.gap-system.org/mailman/listinfo/forum
