Transitive groups issue with `ConjugacyClassesSubgroups`
While testing the ConjugacyClassesSubgroups function on some groups of the TransitiveGroups library, I have found some occasional strange behaviour in some groups.
gap> g := TransitiveGroup(12,288);
[(L(6):2)^2]2=L(6):2wr2
gap> ConjugacyClassesSubgroups(g);;
Error, the collection <elm> must be contained in Source(<map>) at /opt/homebrew/Cellar/gap/4.13.0/libexec/lib/mapping.gi:126 called from
Image( lhom, gps[x] ) at /opt/homebrew/Cellar/gap/4.13.0/libexec/lib/oprtglat.gi:214 called from
func( C[i] ) at /opt/homebrew/Cellar/gap/4.13.0/libexec/lib/coll.gi:663 called from
List( c, function ( x )
return Image( lhom, gps[x] );
end ) at /opt/homebrew/Cellar/gap/4.13.0/libexec/lib/oprtglat.gi:214 called from
ClusterConjugacyPermgroups( G, ShallowCopy( dom )
) at /opt/homebrew/Cellar/gap/4.13.0/libexec/lib/oprtglat.gi:480 called from
SubgroupsOrbitsAndNormalizers( i[1], i[2], false
) at /opt/homebrew/Cellar/gap/4.13.0/libexec/lib/grppccom.gi:1145 called from
... at *stdin*:2
type 'quit;' to quit to outer loop
The same problem happened again later also with TransitiveGroup(10,43).
gap> g := TransitiveGroup(10,43);
[S(5)^2]2
gap> ConjugacyClassesSubgroups(g);
Error, the collection <elm> must be contained in Source(<map>) at /opt/homebrew/Cellar/gap/4.13.0/libexec/lib/mapping.gi:126 called from
Image( lhom, gps[x] ) at /opt/homebrew/Cellar/gap/4.13.0/libexec/lib/oprtglat.gi:214 called from
func( C[i] ) at /opt/homebrew/Cellar/gap/4.13.0/libexec/lib/coll.gi:663 called from
List( c, function ( x )
return Image( lhom, gps[x] );
end ) at /opt/homebrew/Cellar/gap/4.13.0/libexec/lib/oprtglat.gi:214 called from
ClusterConjugacyPermgroups( G, ShallowCopy( dom )
) at /opt/homebrew/Cellar/gap/4.13.0/libexec/lib/oprtglat.gi:480 called from
SubgroupsOrbitsAndNormalizers( i[1], i[2], false
) at /opt/homebrew/Cellar/gap/4.13.0/libexec/lib/grppccom.gi:1145 called from
... at *stdin*:2
type 'quit;' to quit to outer loop
These two groups are the same, the (A5xA5):D8.
I ran the ConjugacyClassesSubgroups function for the list of SmallGroups of size {1 .. 959}/{256,384,512,640,768,896} and this problem did not show up elsewhere
Thank you for taking the time to report this issue, much appreciated!
This works in GAP 4.12.2.
According to git bisect this regression was introduced by f64e30585ec0d4a0d98c2b5c66328c2c82eba7da in PR #5514 by @hulpke
Was already fixed in branch hulpke/work, now put into PR.