Dear Forum,
The new StabChain function in Gap 3.4 is very useful for my work on
graphs and geometries, since I often know the size of a given group
acting on a graph. However, sometimes I only know an upper bound, and
was pleased to see that StabChain offers the option of specifying this
upper bound through the limit parameter. I was disappointed, however,
to find that with this option, StabChain appears to take as long as
when given no extra information, even when this upper bound is
achieved. Please tell me how to fix this!
Best regards, Leonard Soicher.
P.S. Log file illustrating this. Timings are for a Sparc 2.
[... stuff deleted ...] gap> C:=Combinations([1..12],4);; gap> G:=Operation(SymmetricGroup(12),C,OnSets);; gap> Length(C); 495 gap> H:=Copy(G);; gap> Runtime(); 275433 gap> StabChain(H);; gap> Runtime(); 390066 gap> H:=Copy(G);; gap> Runtime(); 390133 gap> StabChain(H,rec(size:=Factorial(12)));; gap> Runtime(); 397816 gap> H:=Copy(G);; gap> Runtime(); 397866 gap> StabChain(H,rec(limit:=Factorial(12)));; gap> Runtime(); 514183 gap> quit;