More changes made to DigraphRemoveAllEdges

Author: rm387

gap/attr.gd

@@ -89,8 +89,7 @@ DeclareAttributeThatReturnsDigraph("DigraphReverse", IsDigraph);
 DeclareAttributeThatReturnsDigraph("DigraphDual", IsDigraph);
 DeclareAttributeThatReturnsDigraph("ReducedDigraph", IsDigraph);
 DeclareAttributeThatReturnsDigraph("DigraphRemoveAllMultipleEdges", IsDigraph);
-DeclareAttributeThatReturnsDigraph("DigraphRemoveAllEdges", IsImmutableDigraph);
-DeclareAttributeThatReturnsDigraph("DigraphRemoveAllEdges", IsMutableDigraph);
+DeclareAttributeThatReturnsDigraph("DigraphRemoveAllEdges", IsDigraph);
 
 # TODO replace all DeclareOperations below to
 # DeclareAttributeThatReturnsDigraph, and remove the *Attr versions.

gap/attr.gi

@@ -2540,18 +2540,13 @@ end);
 InstallMethodThatReturnsDigraph(DigraphRemoveAllEdges,
 "for an immutable digraph",
 [IsImmutableDigraph],
-D -> NullDigraph(DigraphNrVertices(D))
-);
+D -> NullDigraph(DigraphNrVertices(D)));
 
 InstallMethodThatReturnsDigraph(DigraphRemoveAllEdges,
 "for a mutable digraph",
 [IsMutableDigraph],
 function(D)
-  local i, currentEdges;
-  for i in [1 .. Length(OutNeighbours(D))] do
-    currentEdges := DigraphOutEdges(D, i);
-    DigraphRemoveEdges(D, currentEdges);
-  od;
+  D!.OutNeighbours := List(DigraphVertices(D), v -> []);
   return D;
 end);
 

gap/oper.gi

@@ -994,8 +994,8 @@ InstallMethod(SwapDigraphs,
 [IsMutableDigraph, IsMutableDigraph],
 function(D1, D2)
   local nb1, nb2;
-    nb1 := OutNeighboursMutableCopy(D1);
-    nb2 := OutNeighboursMutableCopy(D2);
+    nb1 := OutNeighbours(D1);
+    nb2 := OutNeighbours(D2);
     D1!.OutNeighbours := nb2;
     D2!.OutNeighbours := nb1;
 end);