Create OP "Round" which uses banker's rounding. Not used in Python API tf.round yet.

Change: 136175631

3 files changed, 19 insertions, 3 deletions

diff --git a/tensorflow/core/ops/math_ops.cc b/tensorflow/core/ops/math_ops.cc
index ab062c7601..97515cbb72 100644
--- a/tensorflow/core/ops/math_ops.cc
+++ b/tensorflow/core/ops/math_ops.cc
@@ -259,6 +259,13 @@ Computes reciprocal of square root of x element-wise.
 I.e., \\(y = 1 / \sqrt{x}\\).
 )doc");
 
+REGISTER_OP("Round").UNARY().Doc(R"doc(
+Rounds the values of a tensor to the nearest integer, element-wise.
+
+Rounds half to even.  Also known as bankers rounding. If you want to round
+according to the current system rounding mode use std::cint.
+)doc");
+
 REGISTER_OP("RsqrtGrad").UNARY_GRADIENT_COMPLEX().Doc(R"doc(
 Computes the gradient for the rsqrt of `x` wrt its input.
 
diff --git a/tensorflow/python/ops/math_ops.py b/tensorflow/python/ops/math_ops.py
index 23f141039a..c035673745 100644
--- a/tensorflow/python/ops/math_ops.py
+++ b/tensorflow/python/ops/math_ops.py
@@ -556,11 +556,13 @@ def imag(input, name=None):
 def round(x, name=None):
   """Rounds the values of a tensor to the nearest integer, element-wise.
 
+  Rounds half to even.  Also known as bankers rounding. If you want to round
+  according to the current system rounding mode use tf::cint.
   For example:
 
   ```python
-  # 'a' is [0.9, 2.5, 2.3, -4.4]
-  tf.round(a) ==> [ 1.0, 3.0, 2.0, -4.0 ]
+  # 'a' is [0.9, 2.5, 2.3, 1.5, -4.5]
+  tf.round(a) ==> [ 1.0, 2.0, 2.0, 2.0, -4.0 ]
   ```
 
   Args:
@@ -574,9 +576,14 @@ def round(x, name=None):
   if x.dtype.is_integer:
     return x
   else:
+    # TODO(nolivia): Switch to new Round op
+    # return gen_math_ops.round(x, name=name)
     return gen_math_ops.floor(x + 0.5, name=name)
 
 
+ops.RegisterShape("Round")(common_shapes.call_cpp_shape_fn)
+
+
 def cast(x, dtype, name=None):
   """Casts a tensor to a new type.
 
diff --git a/tensorflow/python/ops/math_ops_test.py b/tensorflow/python/ops/math_ops_test.py
index 50a913ebd8..6bfa13ba0a 100644
--- a/tensorflow/python/ops/math_ops_test.py
+++ b/tensorflow/python/ops/math_ops_test.py
@@ -115,7 +115,9 @@ class RoundTest(test_util.TensorFlowTestCase):
 
   def testRounding(self):
     x = [0.49, 0.7, -0.3, -0.8]
-    for dtype in [np.float32, np.double]:
+    # TODO(nolivia): Remove this when RoundOp is forwards compatible
+    # x = np.arange(-5.0, 5.0, .25)
+    for dtype in [np.float32, np.double, np.int32]:
       x_np = np.array(x, dtype=dtype)
       with self.test_session(use_gpu=True):
         x_tf = constant_op.constant(x_np, shape=x_np.shape)