Don't change constant names in Features

pytensor/graph/features.py

@@ -753,7 +753,8 @@ class PreserveVariableAttributes(Feature):
     """
 
     def on_change_input(self, fgraph, node, i, r, new_r, reason=None):
-        if r.name is not None and new_r.name is None:
+        # Don't change the name of constants
+        if r.owner and r.name is not None and new_r.name is None:
             new_r.name = r.name
         if (
             getattr(r.tag, "nan_guard_mode_check", False)

pytensor/graph/rewriting/basic.py

@@ -588,10 +588,6 @@ def process_atomic(self, fgraph, c):
         sig = c.merge_signature()
         other_c = self.atomic_sig_inv.get(sig, None)
         if other_c is not None:
-            # multiple names will clobber each other..
-            # we adopt convention to keep the last name
-            if c.name:
-                other_c.name = c.name
             self.scheduled.append([[(c, other_c, "merge")]])
         else:
             # this is a new constant

pytensor/scalar/basic.py

@@ -4236,7 +4236,8 @@ def fgraph(self):
         # the fgraph to be set to the variable as we need to pickle
         # them for the cache of c module to work.
         fgraph = FunctionGraph(self.inputs, self.outputs)
-        MergeOptimizer().rewrite(fgraph)
+        with config.change_flags(optimizer_verbose=False):
+            MergeOptimizer().rewrite(fgraph)
         for node in fgraph.apply_nodes:
             if not isinstance(node.op, ScalarOp):
                 raise TypeError(