[GAP Forum] Run GAP command for x seconds

[Frank Lübeck]

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.Luebeck at Math.RWTH-Aachen.De
\\\  WWW:    http://www.math.rwth-aachen.de/~Frank.Luebeck/