[GAP Forum] Exceeded Permitted Memory

[Minghui Liu]

By the way, I found that even better supercomputers are available in my
university:

"Dedicated cluster with up to 192 CPU cores interconnected by
high-performance InfiniBand network can be provisioned within a business
day."

And one needs to pay to use it. Is there any point trying?

Thanks and regards,

Minghui


On 3 May 2014 13:53, Minghui Liu <matliumh at gmail.com> wrote:

> Dear Forum,
>
> I am using GAP to compute a group with hundreds of generators and
> relations. The command AbelianInvariants(F/relations) works perfectly, but
> when I  use the command MaximalAbelianQuotient(F/relations); the following
> message is returned:
>
> gap> phi:=MaximalAbelianQuotient(G);
> Error, exceeded the permitted memory (`-o' command line option) in
>   MakeImmutable( a ); called from
> UnderlyingElement( left ) * UnderlyingElement( right ) called from
> gen[j] ^ s[i][j] called from
> <function "unknown">( <arguments> )
>  called from read-eval loop at line 80 of *stdin*
> you can 'return;'
> brk>
>
> I also tried to run GAP on a supercomputer (HP Xeon four sockets 10-Core
> and two sockets Hexa-Core 64-bit Linux cluster, CentOS 5) but with the same
> result (Does a supercomputer make any difference at all?). Is there any way
> that I can slove this, or should we concluded that my group is "too large"
> to be computed by GAP.
>
> Anyway my goal is to find the torsion elements in F/relations. As I can
> read from AbelianInvariants(F/relations), there are four copies of Z/Z2. Is
> there any other way that I can find and verify the four elements in F whose
> image has order 2 in F/relations?
>
> I very much appreciate your help!
>
> Best regards,
>
> Minghui
>