75 lines
3.3 KiB
C++
75 lines
3.3 KiB
C++
/* Copyright 2017 The TensorFlow Authors. All Rights Reserved.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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==============================================================================*/
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#ifndef TENSORFLOW_CC_OPS_WHILE_LOOP_H_
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#define TENSORFLOW_CC_OPS_WHILE_LOOP_H_
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#include "tensorflow/cc/framework/ops.h"
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#include "tensorflow/cc/framework/scope.h"
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namespace tensorflow {
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namespace ops {
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// Function that takes cond graph inputs and returns cond graph boolean output.
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// 'output' need not be set if an error is returned.
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typedef std::function<Status(const Scope&, const std::vector<Output>& inputs,
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Output* output)>
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CondGraphBuilderFn;
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// Function that takes body graph inputs and returns body graph outputs.
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// 'outputs' need not be populated if an error is returned.
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typedef std::function<Status(const Scope&, const std::vector<Output>& inputs,
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std::vector<Output>* outputs)>
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BodyGraphBuilderFn;
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// Constructs a while loop.
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//
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// Arguments:
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// * scope: used to construct the while loop.
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// * inputs: the initial values of the loop variables. Must be non-empty.
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// * cond: a function that builds the condition graph of the loop. Takes the
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// current loop variables as inputs and returns a scalar boolean Output
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// indicating whether the loop should continue.
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// * body: a function that builds the body graph of the loop. Takes the current
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// loop variables as inputs and returns the updated loop variables.
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// * frame_name: the frame name to use for this while loop. This should be a
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// unique name. This will be used as a prefix for created operations.
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// * outputs: output param that returns final loop variable outputs in non-error
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// case. Must be non-null and empty.
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// * create_while_ctx: if true, a WhileContext is created and populated for this
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// loop. See core/graph/while_context.h for more details on
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// WhileContexts. This is set to false for loops used as part of gradient
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// computations, since they're part of the gradient for a loop in the
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// forward-pass.
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// TODO(skyewm): revisit this. Should we create WhileContexts for all loops,
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// even if we don't need them?
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// * cond_output: if non-null, the output of the predicate is returned. This
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// will always be a LoopCond node.
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//
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// Returns an error if the while loop could not be fully constructed.
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//
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// TODO(skyewm): clean up partially-constructed loop in error case
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// TODO(skyewm): create public interface to this method
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Status BuildWhileLoop(const Scope& scope, const std::vector<Output>& inputs,
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const CondGraphBuilderFn& cond,
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const BodyGraphBuilderFn& body, const string& frame_name,
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OutputList* outputs, bool create_while_ctx = true,
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Output* cond_output = nullptr);
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} // namespace ops
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} // namespace tensorflow
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#endif // TENSORFLOW_CC_OPS_WHILE_LOOP_H_
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