some care for graphs in sage/combinat/posets/d_complete.py

Author: dcoudert

src/sage/combinat/posets/d_complete.py

@@ -89,18 +89,20 @@ def _hooks(self):
 
                 # Check if any of these make a longer double tailed diamond
                 found_diamond = False
-                for (mn, mx) in [(i, j) for i in potential_min for j in potential_max]:
-                    if len(H.neighbors_in(mx)) != 1:
+                for mx in potential_max:
+                    if H.in_degree(mx) != 1:
                         continue
-                    if len(H.all_paths(mn, mx)) == 2:
-                        # Success
-                        min_elmt = mn
-                        max_elmt = mx
-
-                        min_diamond[mx] = mn
-                        max_diamond[mn] = mx
-                        diamond_index[mx] = index
-                        found_diamond = True
+                    for mn in potential_min:
+                        if len(H.all_paths(mn, mx)) == 2:
+                            # Success
+                            min_elmt = mn
+                            max_elmt = mx
+                            min_diamond[mx] = mn
+                            max_diamond[mn] = mx
+                            diamond_index[mx] = index
+                            found_diamond = True
+                            break
+                    if found_diamond:
                         break
                 if not found_diamond:
                     break