Dear GAP-Forum,

Shahriar Mokhtari writes:

I was trying to compute the automorphism of a graph using the command
AutGroupGraph but I got the following error message which I don't know
what to do with.
caygraph is a graph the I already defined for gap.

-----------------------------------
gap> AutGroupGraph( caygraph);
dreadnaut: sorry, no executable exists for this machine
Syntax error: ; expected in /tmp/02762caa line 1
drtogap3: sorry, no executable exists for this machine
^
Error, sorry, the elements of <arg> lie in no common ring domain in
Domain( gens ) called from
Group( GRAPE_dr_sgens, () ) called from
AutGroupGraph( caygraph ) called from
main loop
brk>

The AutGroupGraph function uses that part of the GRAPE package
which is not written in the GAP language alone. In particular,
AutGroupGraph invokes Brendan Mckay's dreadnaut/nauty C programs
along with certain small translation programs (also written in C).

The non-GAP-language part of GRAPE works only under the Unix operating
system, and instructions on how to install this part of GRAPE can be
found in the GAP manual section "Installing the GRAPE Package".

Hope this helps you to use GRAPE more.

Regards, Leonard Soicher.