Use "is" instead of ==, and Reference for dict keys {} in Bijector.

PiperOrigin-RevId: 263629253

tensorflow/python/kernel_tests/distributions/bijector_test.py

@@ -116,6 +116,7 @@ class BrokenBijector(bijector.Bijector):
       raise IntentionallyMissingError
     return math_ops.log(2.)
 
+
 class BijectorTestEventNdims(test.TestCase):
 
   def testBijectorNonIntegerEventNdims(self):
@@ -162,12 +163,8 @@ class BijectorCachingTestBase(object):
     _ = broken_bijector.forward_log_det_jacobian(x, event_ndims=0)
 
     # Now, everything should be cached if the argument is y.
+    broken_bijector.inverse(y)
     broken_bijector.inverse_log_det_jacobian(y, event_ndims=0)
-    try:
-      broken_bijector.inverse(y)
-      broken_bijector.inverse_log_det_jacobian(y, event_ndims=0)
-    except IntentionallyMissingError:
-      raise AssertionError("Tests failed! Cached values not used.")
 
     # Different event_ndims should not be cached.
     with self.assertRaises(IntentionallyMissingError):
@@ -182,11 +179,8 @@ class BijectorCachingTestBase(object):
     _ = broken_bijector.inverse_log_det_jacobian(y, event_ndims=0)
 
     # Now, everything should be cached if the argument is x.
-    try:
+    broken_bijector.forward(x)
-      broken_bijector.forward(x)
+    broken_bijector.forward_log_det_jacobian(x, event_ndims=0)
-      broken_bijector.forward_log_det_jacobian(x, event_ndims=0)
-    except IntentionallyMissingError:
-      raise AssertionError("Tests failed! Cached values not used.")
 
     # Different event_ndims should not be cached.
     with self.assertRaises(IntentionallyMissingError):

tensorflow/python/ops/distributions/bijector_impl.py

@@ -34,6 +34,7 @@ from tensorflow.python.ops import array_ops
 from tensorflow.python.ops import check_ops
 from tensorflow.python.ops import math_ops
 from tensorflow.python.ops.distributions import util as distribution_util
+from tensorflow.python.util import object_identity
 
 
 __all__ = [
@@ -64,12 +65,14 @@ class _Mapping(collections.namedtuple(
   @property
   def x_key(self):
     """Returns key used for caching Y=g(X)."""
-    return (self.x,) + self._deep_tuple(tuple(sorted(self.kwargs.items())))
+    return ((object_identity.Reference(self.x),) +
+            self._deep_tuple(tuple(sorted(self.kwargs.items()))))
 
   @property
   def y_key(self):
     """Returns key used for caching X=g^{-1}(Y)."""
-    return (self.y,) + self._deep_tuple(tuple(sorted(self.kwargs.items())))
+    return ((object_identity.Reference(self.y),) +
+            self._deep_tuple(tuple(sorted(self.kwargs.items()))))
 
   def merge(self, x=None, y=None, ildj_map=None, kwargs=None, mapping=None):
     """Returns new _Mapping with args merged with self.
@@ -108,7 +111,7 @@ class _Mapping(collections.namedtuple(
     new = {} if new is None else new
     for k, v in six.iteritems(new):
       val = old.get(k, None)
-      if val is not None and val != v:
+      if val is not None and val is not v:
         raise ValueError("Found different value for existing key "
                          "(key:{} old_value:{} new_value:{}".format(
                              k, old[k], v))
@@ -119,7 +122,7 @@ class _Mapping(collections.namedtuple(
     """Helper to merge which handles merging one value."""
     if old is None:
       return new
-    elif new is not None and old != new:
+    elif new is not None and old is not new:
       raise ValueError("Incompatible values: %s != %s" % (old, new))
     return old
 
@@ -567,6 +570,7 @@ class Bijector(object):
     self._constant_ildj_map = {}
     self._validate_args = validate_args
     self._dtype = dtype
+    # These dicts can only be accessed using _Mapping.x_key or _Mapping.y_key
     self._from_y = {}
     self._from_x = {}
     if name:

tensorflow/python/util/object_identity.py

@@ -129,6 +129,9 @@ class ObjectIdentityDictionary(collections_abc.MutableMapping):
     for key in self._storage:
       yield key.unwrapped
 
+  def __repr__(self):
+    return "ObjectIdentityDictionary(%s)" % repr(self._storage)
+
 
 class ObjectIdentityWeakKeyDictionary(ObjectIdentityDictionary):
   """Like weakref.WeakKeyDictionary, but compares objects with "is"."""