text: // Tencent is pleased to support the open source community by making ncnn available.
  //
  // Copyright (C) 2017 THL A29 Limited, a Tencent company. All rights reserved.
  //
  // Licensed under the BSD 3-Clause License (the "License"); you may not use this file except
  // in compliance with the License. You may obtain a copy of the License at
  //
  // https://opensource.org/licenses/BSD-3-Clause
  //
  // 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.
  
  #include "sigmoid.h"
  
  #include <math.h>
  
  namespace ncnn {
  
  DEFINE_LAYER_CREATOR(Sigmoid)
  
  Sigmoid::Sigmoid()
  {
      one_blob_only = true;
      support_inplace = true;
  }
  
  int Sigmoid::forward_inplace(Mat& bottom_top_blob, const Option& opt) const
  {
      int w = bottom_top_blob.w;
      int h = bottom_top_blob.h;
      int channels = bottom_top_blob.c;
      int size = w * h;
  
      #pragma omp parallel for num_threads(opt.num_threads)
      for (int q = 0; q < channels; q++)
      {
          float* ptr = bottom_top_blob.channel(q);
  
          for (int i = 0; i < size; i++)
          {
              ptr[i] = static_cast<float>(1.f / (1.f + exp(-ptr[i])));
          }
      }
  
      return 0;
  }
  
  } // namespace ncnn
  