From 9f0cdd5f2f0cbdd7abc3246032f3eb5e3fcb13dc Mon Sep 17 00:00:00 2001
From: Alexander Hulpke <hulpke@math.colostate.edu>
Date: Thu, 12 Oct 2017 08:24:31 -0600
Subject: [PATCH 1/2] ENHANCE: Force abelian test before computing automorphism
 group.

Use RankFilter.
---
 lib/morpheus.gi | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/lib/morpheus.gi b/lib/morpheus.gi
index 0d6c6a04c4..0e10db9330 100644
--- a/lib/morpheus.gi
+++ b/lib/morpheus.gi
@@ -1978,6 +1978,25 @@ local A;
   return A;
 end);
 
+#############################################################################
+##
+#M  AutomorphismGroup(<G>) . . abelian case
+##
+InstallMethod(AutomorphismGroup,"test abelian",true,[IsGroup and IsFinite],
+  RankFilter(IsSolvableGroup and IsFinite),
+function(G)
+local A;
+  if not IsAbelian(G) then
+    TryNextMethod();
+  fi;
+  A:=AutomorphismGroupAbelianGroup(G);
+  SetIsAutomorphismGroup(A,true);
+  SetIsGroupOfAutomorphismsFiniteGroup(A,true);
+  SetIsFinite(A,true);
+  SetAutomorphismDomain(A,G);
+  return A;
+end);
+
 # just in case it does not know to be finite
 RedispatchOnCondition(AutomorphismGroup,true,[IsGroup],
     [IsGroup and IsFinite],0);

From c58a2631b9476bd14978385a681b9189f3990048 Mon Sep 17 00:00:00 2001
From: Alexander Hulpke <hulpke@math.colostate.edu>
Date: Tue, 14 Nov 2017 13:16:23 -0700
Subject: [PATCH 2/2] FIX: Automorphism group structure for type `C' only holds

for n\ge 3. In the case of n=2 it needs to be considered as B2 instead.

This fixes #1902

Added test
---
 lib/morpheus.gi                              |  2 +-
 tst/teststandard/opers/AutomorphismGroup.tst | 21 ++++++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)
 create mode 100644 tst/teststandard/opers/AutomorphismGroup.tst

diff --git a/lib/morpheus.gi b/lib/morpheus.gi
index 0e10db9330..5a703b6ffc 100644
--- a/lib/morpheus.gi
+++ b/lib/morpheus.gi
@@ -1568,7 +1568,7 @@ local d,id,H,iso,aut,auts,i,all,hom,field,dim,P,diag,mats,gens,gal;
       all:=true;
     fi;
 
-  elif id.series in ["L","2A","C"] then
+  elif id.series in ["L","2A"] or (id.series="C" and id.parameter[1]>2) then
     hom:=EpimorphismFromClassical(G);
     if hom=fail then return fail;fi;
     field:=FieldOfMatrixGroup(Source(hom));
diff --git a/tst/teststandard/opers/AutomorphismGroup.tst b/tst/teststandard/opers/AutomorphismGroup.tst
new file mode 100644
index 0000000000..dd7e057226
--- /dev/null
+++ b/tst/teststandard/opers/AutomorphismGroup.tst
@@ -0,0 +1,21 @@
+gap> START_TEST("AutomorphismGroup.tst");
+gap> SimpleAutTest:=function(from,to)
+> local it,g,a,p;
+>   it:=SimpleGroupsIterator(from);
+>   g:=NextIterator(it);
+>   while Size(g)<=to do
+>     a:=AutomorphismGroup(g);
+>     Info(InfoWarning,2,g," ",Size(g)," ",Size(a)/Size(g));
+>     p:=Image(IsomorphismPermGroup(a));
+>     if Size(p)<>Size(a) then
+>       return g;
+>     fi;
+>     g:=NextIterator(it);
+>   od;
+>   return true;
+> end;;
+gap> SimpleAutTest(1,10^5);
+true
+gap> SimpleAutTest(10^5,3*10^6:nopsl2);
+true
+gap> STOP_TEST("AutomorphismGroup.tst",1);