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Diffstat (limited to 'tensorflow/python/autograph/utils/multiple_dispatch.py')
-rw-r--r-- | tensorflow/python/autograph/utils/multiple_dispatch.py | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/tensorflow/python/autograph/utils/multiple_dispatch.py b/tensorflow/python/autograph/utils/multiple_dispatch.py new file mode 100644 index 0000000000..107c8f7a68 --- /dev/null +++ b/tensorflow/python/autograph/utils/multiple_dispatch.py @@ -0,0 +1,56 @@ +# Copyright 2016 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. +# ============================================================================== +"""Utilities for type-dependent behavior used in autograph-generated code.""" + +from __future__ import absolute_import +from __future__ import division +from __future__ import print_function + +from tensorflow.python.autograph.utils.type_check import is_tensor +from tensorflow.python.ops import control_flow_ops + + +def run_cond(condition, true_fn, false_fn): + """Type-dependent functional conditional. + + Args: + condition: A Tensor or Python bool. + true_fn: A Python callable implementing the true branch of the conditional. + false_fn: A Python callable implementing the false branch of the + conditional. + + Returns: + result: The result of calling the appropriate branch. If condition is a + Tensor, tf.cond will be used. Otherwise, a standard Python if statement will + be ran. + """ + if is_tensor(condition): + return control_flow_ops.cond(condition, true_fn, false_fn) + else: + return py_cond(condition, true_fn, false_fn) + + +def py_cond(condition, true_fn, false_fn): + """Functional version of Python's conditional.""" + if condition: + results = true_fn() + else: + results = false_fn() + + # The contract for the branch functions is to return tuples, but they should + # be collapsed to a single element when there is only one output. + if len(results) == 1: + return results[0] + return results |