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