Remove unnecessary Constant cloning from clone_get_equiv

aesara/graph/basic.py

@@ -1061,25 +1061,29 @@ def clone_get_equiv(
     ] = None,
     clone_inner_graphs: bool = False,
 ) -> Dict[Union[Apply, Variable, "Op"], Union[Apply, Variable, "Op"]]:
-    r"""
-    Return a dictionary that maps from `Variable` and `Apply` nodes in the
-    original graph to a new node (a clone) in a new graph.
+    r"""Clone the graph between `inputs` and `outputs` and return a map of the cloned objects.
+
+    This function works by recursively cloning inputs and rebuilding a directed
+    graph from the inputs up.
 
-    This function works by recursively cloning inputs... rebuilding a directed
-    graph from the inputs up to eventually building new outputs.
+    If `memo` already contains entries for some of the objects in the graph,
+    those objects are replaced with their values in `memo` and *not*
+    unnecessarily cloned.
 
     Parameters
     ----------
     inputs
+        Inputs of the graph to be cloned.
     outputs
+        Outputs of the graph to be cloned.
     copy_inputs
-        True means to create the cloned graph from new input
-        nodes (the bottom of a feed-upward graph).
-        False means to clone a graph that is rooted at the original input
-        nodes.
+        ``True`` means to create the cloned graph from cloned input nodes.
+        ``False`` means to clone a graph that is rooted at the original input
+        nodes.  `Constant`\s are *not* cloned.
     copy_orphans
-        When ``True``, new constant nodes are created. When ``False``, original
-        constant nodes are reused in the new graph.
+        When ``True``, inputs with no owners are cloned.  When ``False``,
+        original inputs are reused in the new graph.  Cloning is *not*
+        performed for `Constant`\s.
     memo
         Optionally start with a partly-filled dictionary for the return value.
         If a dictionary is passed, this function will work in-place on that
@@ -1093,7 +1097,7 @@ def clone_get_equiv(
 
     # clone the inputs if necessary
     for input in inputs:
-        if copy_inputs:
+        if not isinstance(input, Constant) and copy_inputs:
             cpy = input.clone()
             cpy.owner = None
             cpy.index = None
@@ -1105,7 +1109,7 @@ def clone_get_equiv(
     for apply in io_toposort(inputs, outputs):
         for input in apply.inputs:
             if input not in memo:
-                if copy_orphans:
+                if not isinstance(input, Constant) and copy_orphans:
                     cpy = input.clone()
                     memo[input] = cpy
                 else: