Allow string keys in eval utility

pytensor/graph/basic.py

@@ -558,6 +558,46 @@ def get_parents(self):
             return [self.owner]
         return []
 
+    def convert_string_keys_to_pytensor_variables(self, inputs_to_values):
+        r"""Convert the string keys to corresponding `Variable` with nearest name.
+
+        Parameters
+        ----------
+        inputs_to_values :
+            A dictionary mapping PyTensor `Variable`\s to values.
+
+        Examples
+        --------
+
+        >>> import numpy as np
+        >>> import pytensor.tensor as at
+        >>> x = at.dscalar('x')
+        >>> y = at.dscalar('y')
+        >>> z = x + y
+        >>> np.allclose(z.eval({'x' : 3, 'y' : 1}), 4)
+        True
+        """
+        process_input_to_values = {}
+        for i in inputs_to_values:
+            if isinstance(i, str):
+                nodes_with_matching_names = get_var_by_name([self], i)
+                length_of_nodes_with_matching_names = len(nodes_with_matching_names)
+                if length_of_nodes_with_matching_names == 0:
+                    raise Exception(f"{i} not found in graph")
+                else:
+                    if length_of_nodes_with_matching_names > 1:
+                        warnings.warn(
+                            f"Found {length_of_nodes_with_matching_names} pytensor variables with name {i} taking the first declared named variable for computation"
+                        )
+                    process_input_to_values[
+                        nodes_with_matching_names[
+                            length_of_nodes_with_matching_names - 1
+                        ]
+                    ] = inputs_to_values[i]
+            else:
+                process_input_to_values[i] = inputs_to_values[i]
+        return process_input_to_values
+
     def eval(self, inputs_to_values=None):
         r"""Evaluate the `Variable`.
 
@@ -597,6 +637,10 @@ def eval(self, inputs_to_values=None):
         if inputs_to_values is None:
             inputs_to_values = {}
 
+        inputs_to_values = self.convert_string_keys_to_pytensor_variables(
+            inputs_to_values
+        )
+
         if not hasattr(self, "_fn_cache"):
             self._fn_cache = dict()
 

tests/graph/test_basic.py

@@ -290,9 +290,11 @@ def test_outputs_clients(self):
 
 class TestEval:
     def setup_method(self):
-        self.x, self.y = scalars("x", "y")
+        self.x, self.y, self.e = scalars("x", "y", "e")
         self.z = self.x + self.y
         self.w = 2 * self.z
+        self.t = self.e + 1
+        self.t.name = "e"
 
     def test_eval(self):
         assert self.w.eval({self.x: 1.0, self.y: 2.0}) == 6.0
@@ -302,6 +304,13 @@ def test_eval(self):
             pickle.loads(pickle.dumps(self.w)), "_fn_cache"
         ), "temporary functions must not be serialized"
 
+    def test_eval_with_strings(self):
+        assert self.w.eval({"x": 1.0, self.y: 2.0}) == 6.0
+        assert self.w.eval({self.z: 3}) == 6.0
+
+    def test_eval_with_strings_with_mulitple_same_name(self):
+        assert self.t.eval({"e": 1.0}) == 2.0
+
 
 class TestAutoName:
     def test_auto_name(self):