Merge pull request #1735 from rizar/fix_eval

theano/gof/graph.py

@@ -415,18 +415,21 @@ class Variable(Node):
         if inputs_to_values is None:
             inputs_to_values = {}
 
-        if not hasattr(self, '_fn'):
-            self._fn_inputs = inputs_to_values.keys()
-            self._fn = theano.function(self._fn_inputs, self)
-        args = [inputs_to_values[param] for param in self._fn_inputs]
+        if not hasattr(self, '_fn_cache'):
+            self._fn_cache = dict()
 
-        rval = self._fn(*args)
+        inputs = tuple(sorted(inputs_to_values.keys(), key=id))
+        if not inputs in self._fn_cache:
+            self._fn_cache[inputs] = theano.function(inputs, self)
+        args = [inputs_to_values[param] for param in inputs]
+
+        rval = self._fn_cache[inputs](*args)
 
         return rval
 
     def __getstate__(self):
         d = self.__dict__.copy()
-        d.pop("_fn", None)
+        d.pop("_fn_cache", None)
         return d
     env = property(env_getter, env_setter, env_deleter)
 

theano/gof/tests/test_graph.py

@@ -297,14 +297,17 @@ class TestIsSameGraph(unittest.TestCase):
 # eval         #
 ################
 
-def test_eval():
-    x = tensor.scalar()
-    y = tensor.scalar()
-    z = x + y
-
-    result = z.eval({x : 1., y : 2.})
-
-    assert result == 3.
-
-    # We don't want to pickle the tmp function.
-    assert not hasattr(pickle.loads(pickle.dumps(z)), '_fn')
+class TestEval(unittest.TestCase):
+
+    def setUp(self):
+        self.x, self.y = tensor.scalars('x', 'y')
+        self.z = self.x + self.y
+        self.w = 2 * self.z
+
+    def test_eval(self):
+        self.assertEquals(self.w.eval({self.x : 1., self.y : 2.}), 6.)
+        self.assertEquals(self.w.eval({self.z : 3}), 6.)
+        self.assertTrue(hasattr(self.w, "_fn_cache"),
+                "variable must have cache after eval")
+        self.assertFalse(hasattr(pickle.loads(pickle.dumps(self.w)), '_fn_cache'),
+                "temporary functions must not be serialized")