1 /* Copyright 2017 The TensorFlow Authors. All Rights Reserved. 2 3 Licensed under the Apache License, Version 2.0 (the "License"); 4 you may not use this file except in compliance with the License. 5 You may obtain a copy of the License at 6 7 http://www.apache.org/licenses/LICENSE-2.0 8 9 Unless required by applicable law or agreed to in writing, software 10 distributed under the License is distributed on an "AS IS" BASIS, 11 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 See the License for the specific language governing permissions and 13 limitations under the License. 14 ==============================================================================*/ 15 #ifndef TENSORFLOW_LITE_KERNELS_ACTIVATION_FUNCTOR_H_ 16 #define TENSORFLOW_LITE_KERNELS_ACTIVATION_FUNCTOR_H_ 17 18 #include <algorithm> 19 #include <cmath> 20 #include <cstdlib> 21 22 #include "tensorflow/lite/c/builtin_op_data.h" 23 24 namespace tflite { 25 26 // Dynamic (non-fused) activation functor. perhaps it is worth having 27 // template instantiation? 28 // TODO(aselle): Make this more efficient by pulling the switch to conv_eval 29 // using template inlining. 30 class ActivationFunctor { 31 public: ActivationFunctor(TfLiteFusedActivation act)32 explicit ActivationFunctor(TfLiteFusedActivation act) : act_(act) {} 33 operator()34 float operator()(float a) const { 35 switch (act_) { 36 case kTfLiteActNone: 37 return a; 38 case kTfLiteActRelu: 39 return a < 0.f ? 0.f : a; 40 case kTfLiteActRelu6: 41 return std::max(0.f, std::min(a, 6.f)); 42 case kTfLiteActTanh: 43 return std::tanh(a); 44 case kTfLiteActSigmoid: 45 return 1.0f / (1.0f + std::exp(-a)); 46 default: 47 // TODO(aselle): More informative fatal error! 48 exit(1); 49 } 50 } 51 52 private: 53 TfLiteFusedActivation act_; 54 }; 55 56 } // namespace tflite 57 58 #endif // TENSORFLOW_LITE_KERNELS_ACTIVATION_FUNCTOR_H_ 59