[GAP Forum] Exceeded Permitted Memory

[Minghui Liu]

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