Inverse need not be a symbolic input in `PermuteRowElements`

pytensor/tensor/basic.py

@@ -3481,20 +3481,18 @@ class PermuteRowElements(Op):
     permutation instead.
     """
 
-    __props__ = ()
+    __props__ = ("inverse",)
+
+    def __init__(self, inverse: bool):
+        super().__init__()
+        self.inverse = inverse
 
-    def make_node(self, x, y, inverse):
+    def make_node(self, x, y):
         x = as_tensor_variable(x)
         y = as_tensor_variable(y)
-        if inverse:  # as_tensor_variable does not accept booleans
-            inverse = as_tensor_variable(1)
-        else:
-            inverse = as_tensor_variable(0)
 
         # y should contain integers
         assert y.type.dtype in integer_dtypes
-        # Inverse should be an integer scalar
-        assert inverse.type.ndim == 0 and inverse.type.dtype in integer_dtypes
 
         # Match shapes of x and y
         x_dim = x.type.ndim
@@ -3511,7 +3509,7 @@ class PermuteRowElements(Op):
         ]
         out_type = tensor(dtype=x.type.dtype, shape=out_shape)
 
-        inputlist = [x, y, inverse]
+        inputlist = [x, y]
         outputlist = [out_type]
         return Apply(self, inputlist, outputlist)
 
@@ -3564,7 +3562,7 @@ class PermuteRowElements(Op):
                 raise ValueError(f"Dimension mismatch: {xs0}, {ys0}")
 
     def perform(self, node, inp, out):
-        x, y, inverse = inp
+        x, y = inp
         (outs,) = out
         x_s = x.shape
         y_s = y.shape
@@ -3587,7 +3585,7 @@ class PermuteRowElements(Op):
         if outs[0] is None or outs[0].shape != out_s:
             outs[0] = np.empty(out_s, dtype=x.dtype)
 
-        self._rec_perform(node, x, y, inverse, outs[0], curdim=0)
+        self._rec_perform(node, x, y, self.inverse, outs[0], curdim=0)
 
     def infer_shape(self, fgraph, node, in_shapes):
         from pytensor.tensor.math import maximum
@@ -3599,14 +3597,14 @@ class PermuteRowElements(Op):
         return [out_shape]
 
     def grad(self, inp, grads):
-        from pytensor.tensor.math import Sum, eq
+        from pytensor.tensor.math import Sum
 
-        x, y, inverse = inp
+        x, y = inp
         (gz,) = grads
         # First, compute the gradient wrt the broadcasted x.
         # If 'inverse' is False (0), apply the inverse of y on gz.
         # Else, apply y on gz.
-        gx = permute_row_elements(gz, y, eq(inverse, 0))
+        gx = permute_row_elements(gz, y, not self.inverse)
 
         # If x has been broadcasted along some axes, we need to sum
         # the gradient over these axes, but keep the dimension (as
@@ -3643,20 +3641,17 @@ class PermuteRowElements(Op):
         if x.type.dtype in discrete_dtypes:
             gx = x.zeros_like()
 
-        # The elements of y and of inverse both affect the output,
+        # The elements of y affect the output,
         # so they are connected to the output,
         # and the transformation isn't defined if their values
         # are non-integer, so the gradient with respect to them is
         # undefined
 
-        return [gx, grad_undefined(self, 1, y), grad_undefined(self, 1, inverse)]
-
-
-_permute_row_elements = PermuteRowElements()
+        return [gx, grad_undefined(self, 1, y)]
 
 
-def permute_row_elements(x, y, inverse=0):
-    return _permute_row_elements(x, y, inverse)
+def permute_row_elements(x, y, inverse=False):
+    return PermuteRowElements(inverse=inverse)(x, y)
 
 
 def inverse_permutation(perm):

pytensor/tensor/rewriting/subtensor.py

@@ -1147,7 +1147,7 @@ def merge_two_slices(fgraph, slice1, len1, slice2, len2):
             val = switch(le(len2, 0), len1 + 1, val)
             val = switch(ge(sl2, len2), len1 + 1, val)
             val = switch(lt(sl2, 0), -len1 - 1, val)
-            if sl1.step:
+            if sl1.step is not None:
                 val = switch(eq(sl1.step, 0), len1 + 1, val)
             return val
     else:

tests/tensor/test_basic.py

@@ -3972,13 +3972,12 @@ class TestInferShape(utt.InferShapeTester):
         advec = dvector()
         aivec = ivector()
 
-        abool = True
         rng = np.random.default_rng(utt.fetch_seed())
         advec_val = random(5)
         aivec_val = rng.permutation(5).astype("int32")
         self._compile_and_check(
             [advec, aivec],
-            [PermuteRowElements()(advec, aivec, abool)],
+            [PermuteRowElements(inverse=True)(advec, aivec)],
             [advec_val, aivec_val],
             PermuteRowElements,
         )
@@ -3986,7 +3985,7 @@ class TestInferShape(utt.InferShapeTester):
         admat_val = random(3, 5)
         self._compile_and_check(
             [admat, aivec],
-            [PermuteRowElements()(admat, aivec, abool)],
+            [PermuteRowElements(inverse=False)(admat, aivec)],
             [admat_val, aivec_val],
             PermuteRowElements,
         )
@@ -3995,7 +3994,7 @@ class TestInferShape(utt.InferShapeTester):
         adtens3_val = random(3, 2, 5)
         self._compile_and_check(
             [adtens3, aivec],
-            [PermuteRowElements()(adtens3, aivec, abool)],
+            [PermuteRowElements(inverse=True)(adtens3, aivec)],
             [adtens3_val, aivec_val],
             PermuteRowElements,
         )
@@ -4008,7 +4007,7 @@ class TestInferShape(utt.InferShapeTester):
         admat_val = random(3, 5)
         self._compile_and_check(
             [admat, aimat],
-            [PermuteRowElements()(admat, aimat, abool)],
+            [PermuteRowElements(inverse=False)(admat, aimat)],
             [admat_val, aimat_val],
             PermuteRowElements,
         )
@@ -4023,7 +4022,7 @@ class TestInferShape(utt.InferShapeTester):
         aitens3_val[1, ::, ::] = bimat_val
         self._compile_and_check(
             [admat, aitens3],
-            [PermuteRowElements()(admat, aitens3, abool)],
+            [PermuteRowElements(inverse=True)(admat, aitens3)],
             [admat_val, aitens3_val],
             PermuteRowElements,
         )