meataxe: fix SMTX.BasisInOrbit for 1-dim modules

gap-system · Dec 21, 2016 · e7f49ae · e7f49ae
1 parent 5188e97
commit e7f49ae
Showing 1 changed file with 10 additions and 5 deletions.
diff --git a/lib/meataxe.gi b/lib/meataxe.gi
@@ -3238,7 +3238,7 @@ SMTX_BasisInOrbit:=function( module )
  leadpos:=SubGModLeadPos(ans,dim,subdim,zero);
 
  i:=1;
- while i <= subdim do
+ while i <= subdim and subdim < dim do
  for l in [1..ngens] do
  m:=matrices[l];
  # apply generator m to submodule generator i
@@ -3254,7 +3254,9 @@ SMTX_BasisInOrbit:=function( module )
  od;
 
  j:=1;
- while j <= dim and normedw[j] = zero do j:=j + 1; od;
+ while j <= dim and normedw[j] = zero do
+ j:=j + 1;
+ od;
  if j <= dim then
  # we have found a new generator of the submodule
  subdim:=subdim + 1;
@@ -3263,14 +3265,17 @@ SMTX_BasisInOrbit:=function( module )
  Add( ans, w );
  Add( normedans, normedw );
  if subdim = dim then
- ans:=ImmutableMatrix(F,ans);
- SMTX.SetBasisInOrbit(module,ans);
- return ans;
+ break;
  fi;
  fi;
  od;
  i:=i + 1;
  od;
+
+ Assert(0, subdim = dim);
+ ans:=ImmutableMatrix(F,ans);
+ SMTX.SetBasisInOrbit(module,ans);
+ return ans;
 end;
 SMTX.BasisInOrbit:=SMTX_BasisInOrbit;