[GAP Forum] Run GAP command for x seconds

[Carl-Fredrik Nyberg Brodda (MTH - Postgraduate Researcher)]

Hi,

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.

Best,
Carl-Fredrik Nyberg Brodda
________________________________
From: Frank Lübeck <frank.luebeck at math.rwth-aachen.de>
Sent: Wednesday, January 27, 2021 3:53 PM
To: Carl-Fredrik Nyberg Brodda (MTH - Postgraduate Researcher) <C.Nyberg-Brodda at uea.ac.uk>
Cc: forum at gap-system.org <forum at gap-system.org>
Subject: Re: [GAP Forum] Run GAP command for x seconds

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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
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