# Copyright 2017 The TensorFlow Authors. All Rights Reserved.

#

# Licensed under the Apache License, Version 2.0 (the "License");

# you may not use this file except in compliance with the License.

# You may obtain a copy of the License at

#

# http://www.apache.org/licenses/LICENSE-2.0

#

# Unless required by applicable law or agreed to in writing, software

# distributed under the License is distributed on an "AS IS" BASIS,

# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

# See the License for the specific language governing permissions and

# limitations under the License.

# ==============================================================================

"""Experimental API for TensorFlow's "Eager" mode of execution."""

from __future__ import absolute_import

from __future__ import division

from __future__ import print_function

import numpy as np

# TODO(agarwal): get rid of this import and change callers to use the classes in

# ops.py.

# pylint: disable=unused-import

from tensorflow.python.framework.ops import _tensor_from_handle

from tensorflow.python.framework.ops import convert_n_to_eager_tensor

from tensorflow.python.framework.ops import convert_to_eager_tensor

from tensorflow.python.framework.ops import EagerTensor as Tensor

# pylint: enable=unused-import

class _Op(object):

"""Fake op for _LazyZero to make its python API tf.Tensor-like."""

def __init__(self):

self.type = "Zeros"

class LazyZero(object):

"""Lazily-instantiated zero-valued Tensor used as autograd accumulator."""

def __init__(self, shape, dtype):

self.shape = shape

self.dtype = dtype

self.op = _Op()

def __add__(self, other):

return other

def __radd__(self, other):

return other

def numpy(self):

return np.zeros(self.shape, self.dtype)