/*
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* Copyright (C) 2017 The Android Open Source Project
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*
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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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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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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 ANDROID_ML_NN_ACTIVATION_FUNCTOR_H
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#define ANDROID_ML_NN_ACTIVATION_FUNCTOR_H
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#include "android/log.h"
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#include <algorithm>
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#include <cmath>
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enum ActivationFn {
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kActivationNone = 0,
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kActivationRelu,
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kActivationRelu1,
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kActivationRelu6,
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kActivationTanh,
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kActivationSignBit,
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kActivationSigmoid,
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};
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class ActivationFunctor {
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public:
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explicit ActivationFunctor(ActivationFn act) : act_(act) {}
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float operator()(float a) const {
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switch (act_) {
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case kActivationNone:
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return a;
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case kActivationRelu:
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return a < 0.f ? 0.f : a;
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case kActivationRelu6:
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return std::max(0.f, std::min(a, 6.f));
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case kActivationTanh:
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return std::tanh(a);
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case kActivationSigmoid:
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return 1.0f / (1.0f + std::exp(-a));
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default:
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__android_log_print(ANDROID_LOG_ERROR, "NN API",
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"Invalid enum value for activation function: 0x%0X",
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act_);
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abort();
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}
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}
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private:
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ActivationFn act_;
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};
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#endif // ANDROID_ML_NN_ACTIVATION_FUNCTOR_H
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