text: #pragma once
  #include "loss_layer.h"
  
  // the output layer (multi-class vertex classification)
  class sigmoid_loss_layer : public loss_layer {
    public:
      sigmoid_loss_layer() { }
      sigmoid_loss_layer(int nv, int n_cls) : loss_layer(nv, n_cls, NULL) { }
      sigmoid_loss_layer(int nv, int n_cls, label_t* ptr) : loss_layer(nv, n_cls, ptr) { }
      virtual void forward(size_t begin, size_t end, mask_t* masks);
      virtual void backward(size_t begin, size_t end, mask_t* masks, float* grad_out);
      virtual acc_t get_prediction_loss(size_t begin, size_t end, size_t count, mask_t* masks);
  };
  