Remove OrderedDict from scan/op

pytensor/scan/op.py

@@ -46,7 +46,6 @@ relies on the following elements to work properly :
 import dataclasses
 import logging
 import time
-from collections import OrderedDict
 from collections.abc import Callable, Iterable
 from copy import copy
 from itertools import chain, product
@@ -2188,7 +2187,7 @@ class Scan(Op, ScanMethodsMixin, HasInnerGraph):
         #   corresponding outer inputs that the Scan would use as input for
         #   any given iteration. For simplicity, we use iteration 0.
         inner_ins_shapes = []
-        out_equivalent = OrderedDict()
+        out_equivalent = {}
 
         # The two following blocks are commented as it cause in some
         # cases extra scans in the graph. See gh-XXX for the
@@ -2469,7 +2468,7 @@ class Scan(Op, ScanMethodsMixin, HasInnerGraph):
                 if (x in diff_inputs)
                 and get_inp_idx(self_inputs.index(x)) in connected_inputs
             ]
-            gmp = OrderedDict()
+            gmp = {}
 
             # Required in case there is a pair of variables X and Y, with X
             # used to compute Y, for both of which there is an external
@@ -2478,7 +2477,7 @@ class Scan(Op, ScanMethodsMixin, HasInnerGraph):
             # it will be the sum of the external gradient signal and the
             # gradient obtained by propagating Y's external gradient signal
             # to X.
-            known_grads = OrderedDict([(k.copy(), v) for (k, v) in known_grads.items()])
+            known_grads = {k.copy(): v for (k, v) in known_grads.items()}
 
             grads = grad(
                 cost=None,
@@ -2548,7 +2547,7 @@ class Scan(Op, ScanMethodsMixin, HasInnerGraph):
                 dC_dXt = safe_new(dC_douts[idx][0])
             dC_dXts.append(dC_dXt)
 
-        known_grads = OrderedDict()
+        known_grads = {}
         dc_dxts_idx = 0
         for i in range(len(diff_outputs)):
             if i < idx_nitsot_start or i >= idx_nitsot_end: