On Wed, Jan 27, 2021 at 04:54:03PM +0000, Carl-Fredrik Nyberg Brodda (MTH - Postgraduate Researcher) wrote: > Thank you for your response. I am having trouble getting the timeout to > work. Do you have an example of using the timeout? > > I have attempted to pass the last (third, optional) argument of > ParTakeFirstResultByFork as rec(TimeOut := rec(tv_sec :=2, tv_usec := 0)), > hoping for my execution to run for 2 seconds, but this does not work (it > never times out). I have also tried setting the tv_sec record to be the > current time (plus 10 seconds or so), but this does not time out either.
Hi, This looks correct and it works for me, for example: gap> Runtimes(); ParTakeFirstResultByFork([function(x) while true do od; end], [[1]],rec(TimeOut := rec(tv_sec :=2, tv_usec := 0 ))); Runtimes(); rec( system_time := 90, system_time_children := 15, user_time := 1103, user_time_children := 3985 ) [ ] rec( system_time := 94, system_time_children := 15, user_time := 1103, user_time_children := 5984 ) I'm only using Linux systems. Some functions of the IO package may not work as expected when GAP is used in Windows (but I don't know the details). Best regards again, Frank Lübeck > Best, > Carl-Fredrik Nyberg Brodda > ________________________________ > From: Frank Lübeck <frank.lueb...@math.rwth-aachen.de> > Sent: Wednesday, January 27, 2021 3:53 PM > To: Carl-Fredrik Nyberg Brodda (MTH - Postgraduate Researcher) > <c.nyberg-bro...@uea.ac.uk> > Cc: forum@gap-system.org <forum@gap-system.org> > Subject: Re: [GAP Forum] Run GAP command for x seconds > > On Wed, Jan 27, 2021 at 02:53:14PM +0000, Carl-Fredrik Nyberg Brodda (MTH - > Postgraduate Researcher) wrote: > > Hi all, > > > > A problem which I recently stumbled upon is the following: is there a way > > to execute a given GAP command only for a certain amount of time, before > > stepping past the command and continuing execution? > > > > Let us say I have a table of finitely many finitely presented groups, > > and wish to see whether GAP has a "naive" solution for their word > > problem. I find a KnuthBendixRewritingSystem() of the group, and then run > > MakeConfluent() on this rewriting system. Of course, this process may not > > terminate at all! But sometimes it does. My problem is essentially that > > I wish to run MakeConfluent() for some amount of time (say 5 seconds), > > and then, if the command has not terminated, continue on with the next > > group. This avoids all decidability issues, and would in other programming > > languages be easily implemented with a timer. > > > > Of course the problem is general, so the above is just a use-case. Is > > there something that can help with this? > > > > Best, > > Carl-Fredrik Nyberg Brodda > > Dear Forum, > > I have used successfully the function > ParTakeFirstResultByFork > from the IO package for this kind of applications. > It has an optional third argument which allows to specify a timeout. > > Best regards, > Frank -- /// Dr. Frank Lübeck, Lehrstuhl für Algebra und Zahlentheorie, \\\ Pontdriesch 14/16, 52062 Aachen, Germany /// E-mail: frank.lueb...@math.rwth-aachen.de \\\ WWW: http://www.math.rwth-aachen.de/~Frank.Luebeck/ _______________________________________________ Forum mailing list Forum@gap-system.org https://mail.gap-system.org/mailman/listinfo/forum
