From aa2cacd6627ffb296bedc910c957a0fd4a2f957f Mon Sep 17 00:00:00 2001
From: Siddharth Agrawal <siddharth.950@gmail.com>
Date: Fri, 1 Jul 2016 01:59:14 +0530
Subject: [PATCH] Enable tf.erf() for SparseTensor (#3122)

---
 .../python/kernel_tests/cwise_ops_test.py     |  4 ++++
 tensorflow/python/ops/math_ops.py             | 19 +++++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/tensorflow/python/kernel_tests/cwise_ops_test.py b/tensorflow/python/kernel_tests/cwise_ops_test.py
index 7f1be574bbf..093da97469a 100644
--- a/tensorflow/python/kernel_tests/cwise_ops_test.py
+++ b/tensorflow/python/kernel_tests/cwise_ops_test.py
@@ -215,6 +215,7 @@ class UnaryOpTest(tf.test.TestCase):
     self._compareBothSparse(z, np.sqrt, tf.sqrt, tol=1e-3)
     self._compareBothSparse(x, np.tanh, tf.tanh)
     self._compareBothSparse(y, np.sign, tf.sign)
+    self._compareBothSparse(x, np.vectorize(math.erf), tf.erf)
 
   def testFloatTanhEdge(self):
     x = np.arange(40, 40 + 6).reshape(6).astype(np.float32)
@@ -254,6 +255,7 @@ class UnaryOpTest(tf.test.TestCase):
     self._compareBothSparse(x, np.sqrt, tf.sqrt, tol=1e-3)
     self._compareBothSparse(x, np.tanh, tf.tanh)
     self._compareBothSparse(x, np.sign, tf.sign)
+    self._compareBothSparse(x, np.sign, tf.erf)
 
   def testDoubleBasic(self):
     x = np.arange(-3, 3).reshape(1, 3, 2).astype(np.float64)
@@ -292,6 +294,7 @@ class UnaryOpTest(tf.test.TestCase):
     self._compareBothSparse(z, np.sqrt, tf.sqrt, tol=1e-3)
     self._compareBothSparse(x, np.tanh, tf.tanh)
     self._compareBothSparse(y, np.sign, tf.sign)
+    self._compareBothSparse(x, np.vectorize(math.erf), tf.erf)
 
   def testHalfBasic(self):
     x = np.arange(-3, 3).reshape(1, 3, 2).astype(np.float16)
@@ -325,6 +328,7 @@ class UnaryOpTest(tf.test.TestCase):
     self._compareBothSparse(z, np.sqrt, tf.sqrt, tol=1e-3)
     self._compareBothSparse(x, np.tanh, tf.tanh)
     self._compareBothSparse(y, np.sign, tf.sign)
+    self._compareBothSparse(x, np.vectorize(math.erf), tf.erf, tol=1e-3)
 
   def testInt32Basic(self):
     x = np.arange(-6, 6, 2).reshape(1, 3, 2).astype(np.int32)
diff --git a/tensorflow/python/ops/math_ops.py b/tensorflow/python/ops/math_ops.py
index 0a76450c5b1..38c7e515941 100644
--- a/tensorflow/python/ops/math_ops.py
+++ b/tensorflow/python/ops/math_ops.py
@@ -348,6 +348,25 @@ def sqrt(x, name=None):
       return gen_math_ops.sqrt(x, name=name)
 
 
+def erf(x, name=None):
+  """Computes the Gauss error function of `x` element-wise.
+
+  Args:
+    x: A `Tensor` of `SparseTensor`. Must be one of the following types: `half`,
+      `float32`, `float64`.
+    name: A name for the operation (optional).
+
+  Returns:
+    A `Tensor` or `SparseTensor`, respectively. Has the same type as `x`.
+  """
+  with ops.op_scope([x], name, "Erf") as name:
+    if isinstance(x, ops.SparseTensor):
+      x_erf = gen_math_ops.erf(x.values, name=name)
+      return ops.SparseTensor(indices=x.indices, values=x_erf, shape=x.shape)
+    else:
+      return gen_math_ops.erf(x, name=name)
+
+
 def complex_abs(x, name=None):
   r"""Computes the complex absolute value of a tensor.