Howdy, This is very helpful! I had not heard of SCSCP before.
It sounds like the idea is to have a GAP-to-GAP transfer via a TCP socket - so really the "threading" comes from the ability to run a procedure on "many" GAP instances. I see there is configpars.g, which suggests approaches to how many ports/servers might be open, and then I can create all of my processes at once using ParListWithSCSCP. Does this sound right? I am curious - if I want to run on n cores, do I need to open GAP n+1 times? Thank you again, Alan On Tue, May 18, 2021 at 2:26 AM Sergio Siccha <ser...@mathb.rwth-aachen.de> wrote: > 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
