09d0ef73ff
Adding an HLO pass that expands the kLogistic HLO into a desired sequence of different HLOs. Currently two different strategies are added. 1) A lowering through an expansion using TAHN (0.5 + 0.5 * tanh(0.5 * x)) 2) A lowering through an expansion using EXP (1.0 / (1.0 + exp(-x))) PiperOrigin-RevId: 318208462 Change-Id: Ibcfba8e95f76c85cdbffc42566f5cec5e663c72b
54 lines
2.0 KiB
C++
54 lines
2.0 KiB
C++
/* Copyright 2020 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_COMPILER_XLA_SERVICE_LOGISTIC_EXPANDER_H_
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#define TENSORFLOW_COMPILER_XLA_SERVICE_LOGISTIC_EXPANDER_H_
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#include <utility>
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#include "tensorflow/compiler/xla/service/hlo_module.h"
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#include "tensorflow/compiler/xla/service/hlo_pass_interface.h"
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#include "tensorflow/compiler/xla/service/op_expander_pass.h"
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namespace xla {
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enum class LogisticExpansionType {
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kTanh, // Expands as 0.5 + 0.5*tanh(0.5*x)
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kExp, // Expands as 1.0 / (1.0 + exp(-x))
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};
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// A pass which performs expansion of the logistic function.
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class LogisticExpander : public OpExpanderPass {
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public:
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explicit LogisticExpander(LogisticExpansionType expansion_type)
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: expansion_type_(expansion_type) {}
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~LogisticExpander() override = default;
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absl::string_view name() const override { return "logistic-expander"; }
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private:
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// Returns `true` if `instruction` should be expanded by this pass.
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bool InstructionMatchesPattern(HloInstruction* instruction) override;
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// Returns a replacement for `instruction`, or nullptr if no replacement is
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// needed (e.g. only the to_apply subcomputation of the instruction was
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// modified).
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StatusOr<HloInstruction*> ExpandInstruction(
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HloInstruction* instruction) override;
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LogisticExpansionType expansion_type_;
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};
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} // namespace xla
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#endif // TENSORFLOW_COMPILER_XLA_SERVICE_LOGISTIC_EXPANDER_H_
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