add seen set

Author: ferrine

pytensor/graph/basic.py

@@ -1088,13 +1088,18 @@ def truncated_graph_inputs(
         return truncated_inputs
 
     blockers: Set[Variable] = set(ancestors_to_include)
+    # variables that go here are under check already, do not repeat the loop for them
+    seen: Set[Variable] = set()
     # enforce O(1) check for node in ancestors to include
     ancestors_to_include = blockers.copy()
 
     while candidates:
         # on any new candidate
         node = candidates.pop()
-
+        if node in seen:
+            continue
+        else:
+            seen.add(node)
         # There was a repeated reference to this node, we have already investigated it
         if node in truncated_inputs:
             continue