Internal Change.

PiperOrigin-RevId: 175307445

1 files changed, 58 insertions, 0 deletions

diff --git a/tensorflow/contrib/lite/kernels/activation_functor.h b/tensorflow/contrib/lite/kernels/activation_functor.h
new file mode 100644
index 0000000000..cfb3369e99
--- /dev/null
+++ b/tensorflow/contrib/lite/kernels/activation_functor.h
@@ -0,0 +1,58 @@
+/* Copyright 2017 The TensorFlow Authors. All Rights Reserved.
+
+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 THIRD_PARTY_TENSORFLOW_CONTRIB_LITE_KERNELS_ACTIVATION_FUNCTOR_H_
+#define THIRD_PARTY_TENSORFLOW_CONTRIB_LITE_KERNELS_ACTIVATION_FUNCTOR_H_
+
+#include <algorithm>
+#include <cmath>
+#include <cstdlib>
+
+#include "tensorflow/contrib/lite/builtin_op_data.h"
+
+namespace tflite {
+
+// Dynamic (non-fused) activation functor. perhaps it is worth having
+// template instantiation?
+// TODO(aselle): Make this more efficient by pulling the switch to conv_eval
+// using template inlining.
+class ActivationFunctor {
+ public:
+  explicit ActivationFunctor(TfLiteFusedActivation act) : act_(act) {}
+
+  float operator()(float a) const {
+    switch (act_) {
+      case kTfLiteActNone:
+        return a;
+      case kTfLiteActRelu:
+        return a < 0.f ? 0.f : a;
+      case kTfLiteActRelu6:
+        return std::max(0.f, std::min(a, 6.f));
+      case kTfLiteActTanh:
+        return std::tanh(a);
+      case kTfLiteActSigmoid:
+        return 1.0f / (1.0f + std::exp(-a));
+      default:
+        // TODO(aselle): More informative fatal error!
+        exit(1);
+    }
+  }
+
+ private:
+  TfLiteFusedActivation act_;
+};
+
+}  // namespace tflite
+
+#endif  // THIRD_PARTY_TENSORFLOW_CONTRIB_LITE_KERNELS_ACTIVATION_FUNCTOR_H_