[GAP Forum] Automorphism Group as Permutation group on Conj.Classes

[Giulio Peruginelli]

Dear GAP-Forum members,
I have a finite group G and I want to compute a representation of Aut(G)
as a permutation group on the set of the conjugacy classes of G.

So I wrote down these lines in Gap 3 (I am using this version; I don't
know if there exists a command or a package to do it directly), where G
is a finite group (in my case it's already been identified in the
SmallGroup library):

   AutG:=AutomorphismGroup(G);
   C:=ConjugacyClasses(G);         
   D:=[];
   for k in [1..Length(C)] do
      D[k]:=Representative(C[k]);
   od;
   AutG1:=Operation(AutG,D);

But I have encountered some problems with certains groups of the
smallgroup library and I don't know why....
For example SmallGroup(12,1) or even SmallGroup(16,8).
Here it is the error message I get, at the last line of the above ones:

> AutG1:=Operation(AutG,D);
> Error, List Element: <list>[8] must have a value at
> prm[i] := pos[PositionSorted( set, D[i] ^ gen )] ... in
> arg[1].operations.Operation( arg[1], arg[2], OnPoints ) called from
> Operation( AutG, D ) called from
> main loop
> brk>
> 

Thanks in advance

Giulio Peruginelli

PhD student in Pisa.