Change the semantics of the `set` and `add` helpers

pytensor/tensor/variable.py

@@ -820,35 +820,36 @@ class _tensor_py_operators:
         """Return selected slices only."""
         return at.extra_ops.compress(self, a, axis=axis)
 
-    def set(self, y, **kwargs):
-        """Return a copy of a tensor with the indexed values set to y.
+    def set(self, idx, y, **kwargs):
+        """Return a copy of self with the indexed values set to y.
 
-        Self must be the output of an indexing operation.
-
-        Equivalent to set_subtensor(self, y). See docstrings for kwargs.
+        Equivalent to set_subtensor(self[idx], y). See docstrings for kwargs.
 
         Examples
         --------
-
-        >>> x = matrix()
-        >>> out = x[0].set(5)
+        >>> import pytensor.tensor as pt
+        >>>
+        >>> x = pt.ones((3,))
+        >>> out = x.set(1, 2)
+        >>> out.eval()  # array([1., 2., 1.])
         """
-        return at.subtensor.set_subtensor(self, y, **kwargs)
-
-    def add(self, y, **kwargs):
-        """Return a copy of a tensor with the indexed values incremented by y.
+        return at.subtensor.set_subtensor(self[idx], y, **kwargs)
 
-        Self must be the output of an indexing operation.
+    def add(self, idx, y, **kwargs):
+        """Return a copy of self with the indexed values incremented by y.
 
-        Equivalent to inc_subtensor(self, y). See docstrings for kwargs.
+        Equivalent to inc_subtensor(self[idx], y). See docstrings for kwargs.
 
         Examples
         --------
 
-        >>> x = matrix()
-        >>> out = x[0].add(5)
+        >>> import pytensor.tensor as pt
+        >>>
+        >>> x = pt.ones((3,))
+        >>> out = x.add(1, 2)
+        >>> out.eval()  # array([1., 3., 1.])
         """
-        return at.inc_subtensor(self, y, **kwargs)
+        return at.inc_subtensor(self[idx], y, **kwargs)
 
 
 class TensorVariable(

tests/tensor/test_variable.py

@@ -438,14 +438,8 @@ class TestTensorInstanceMethods:
         idx = [0]
         y = 5
 
-        assert equal_computations([x[idx].set(y)], [set_subtensor(x[idx], y)])
-        assert equal_computations([x[idx].add(y)], [inc_subtensor(x[idx], y)])
-
-        msg = "must be the result of a subtensor operation"
-        with pytest.raises(TypeError, match=msg):
-            x.set(y)
-        with pytest.raises(TypeError, match=msg):
-            x.add(y)
+        assert equal_computations([x.set(idx, y)], [set_subtensor(x[idx], y)])
+        assert equal_computations([x.add(idx, y)], [inc_subtensor(x[idx], y)])
 
     def test_set_item_error(self):
         x = matrix("x")