#include "full_connected.hpp"

namespace Layer{
  FullConnectedLayer::FullConnectedLayer(size_t n,size_t m):Layer(n,m){
    b=init_vector(m); //b
    w=init_vector(m*n); //w
    nabla_b=init_vector(m); //nabla_b
    nabla_w=init_vector(m*n); //nabla_w
  }

  FullConnectedLayer::~FullConnectedLayer(){
    delete_vector(b);
    delete_vector(w);
    delete_vector(nabla_b);
    delete_vector(nabla_w);
  }

  void
  FullConnectedLayer::init(Real mu,Real sigma){
    default_random_engine generator;
    normal_distribution<Real> distribution(mu,sigma);
    for(size_t i=0;i<m;++i){
      b[i]=distribution(generator);
    }
    for(size_t i=0;i<m*n;++i){
      w[i]=distribution(generator);
    }
  }

  void
  FullConnectedLayer::init_standard(){
    default_random_engine generator;
    normal_distribution<Real> distribution(0,1);
    for(size_t i=0;i<m;++i){
      b[i]=distribution(generator);
    }
    for(size_t i=0;i<m*n;++i){
      normal_distribution<Real> distribution2(0,1/sqrt(n));
      w[i]=distribution2(generator);
    }
  }

  Vector
  FullConnectedLayer::feed_forward(Vector x_){
    x=x_;
    for(size_t i=0;i<m;++i){
      Real temp=b[i];
      for(size_t j=0;j<n;++j){
        temp+=w[indice2(i,j,n)]*x[j];
      }
      y[i]=temp;
    }
    return y;
  }

  void
  FullConnectedLayer::init_nabla(){
    for(size_t i=0;i<m;++i){
      nabla_b[i]=0;
    }
    for(size_t i=0;i<m*n;++i){
      nabla_w[i]=0;
    }
  }

  Vector
  FullConnectedLayer::back_propagation(Vector e){
    for(size_t i=0;i<n;++i){
      Real temp=0;
      for(size_t j=0;j<m;++j){
        temp+=w[indice2(j,i,n)]*e[j];
      }
      d[i]=temp;
    }
    //Update nabla_b
    for(size_t i=0;i<m;++i){
      nabla_b[i]+=e[i];
    }
    //Update nabla_w
    for(size_t i=0;i<m;++i){
      for(size_t j=0;j<n;++j){
        nabla_w[indice2(i,j,n)]+=e[i]*x[j];
      }
    }
    return d;
  }

  void
  FullConnectedLayer::update(Real eta){
    //Update b
    for(size_t i=0;i<m;++i){
      b[i]-=eta*nabla_b[i];
    }
    //Update w
    for(size_t i=0;i<m*n;++i){
      w[i]-=eta*nabla_w[i];
    }
  }
}