Merge changes from github.

PiperOrigin-RevId: 184897758

1 files changed, 17 insertions, 0 deletions

diff --git a/tensorflow/contrib/solvers/python/ops/util.py b/tensorflow/contrib/solvers/python/ops/util.py
index 777e0c185d..96947e8eea 100644
--- a/tensorflow/contrib/solvers/python/ops/util.py
+++ b/tensorflow/contrib/solvers/python/ops/util.py
@@ -45,6 +45,23 @@ def create_operator(matrix):
       apply_adjoint=lambda v: math_ops.matmul(matrix, v, adjoint_a=True))
 
 
+def identity_operator(matrix):
+  """Creates a linear operator from a rank-2 identity tensor."""
+
+  linear_operator = collections.namedtuple(
+      "LinearOperator", ["shape", "dtype", "apply", "apply_adjoint"])
+  shape = matrix.get_shape()
+  if shape.is_fully_defined():
+    shape = shape.as_list()
+  else:
+    shape = array_ops.shape(matrix)
+  return linear_operator(
+      shape=shape,
+      dtype=matrix.dtype,
+      apply=lambda v: v,
+      apply_adjoint=lambda v: v)
+
+
 # TODO(rmlarsen): Measure if we should just call matmul.
 def dot(x, y):
   return math_ops.reduce_sum(math_ops.conj(x) * y)