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C++ TheMatrix::ElementWiseMult方法代码示例

本文整理汇总了C++中TheMatrix::ElementWiseMult方法的典型用法代码示例。如果您正苦于以下问题:C++ TheMatrix::ElementWiseMult方法的具体用法?C++ TheMatrix::ElementWiseMult怎么用?C++ TheMatrix::ElementWiseMult使用的例子?那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在TheMatrix的用法示例。


在下文中一共展示了TheMatrix::ElementWiseMult方法的3个代码示例,这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞,您的评价将有助于系统推荐出更棒的C++代码示例。

示例1: LossAndGrad

/**  
 *  Compute loss and partial derivative of hinge loss w.r.t f
 *   
 *  @param loss [write] loss value computed.
 *  @param f [r/w] = X*w
 *  @param l [write] partial derivative of loss w.r.t. f
 */
void CLogisticLoss::LossAndGrad(double& loss, TheMatrix& f, TheMatrix& l)
{
    l.Zero();  // for gradient computation i.e. grad := l'*X
    f.ElementWiseMult(_data->labels());
    double* f_array = f.Data();  // pointer to memory location of f (faster element access)
    int len = f.Length();	
    double exp_yf = 0.0;

    for(int i=0; i < len; i++)
    {
	if(fabs(f_array[i]) == 0.0)
        {
            loss += LN2;
            l.Set(i,-0.5);
        }
        else if (f_array[i] > 0.0)
        {
            exp_yf = exp(-f_array[i]);
            loss += log(1+exp_yf);
            l.Set(i,-exp_yf/(1+exp_yf));
        }
        else
        {
            exp_yf = exp(f_array[i]);
            loss += log(1+exp_yf) - f_array[i];
            l.Set(i,-1.0/(1+exp_yf));
        }
    }	
    l.ElementWiseMult(_data->labels());
}
开发者ID:funkey,项目名称:bmrm,代码行数:37,代码来源:logisticloss.cpp

示例2: LossAndGrad

/**  
 *  Compute loss and gradient of Huber hinge loss. 
 *  CAUTION: f is passed by reference and is changed within this
 *  function. This is done for efficiency reasons, otherwise we would
 *  have had to create a new copy of f.
 *   
 *  @param loss [write] loss value computed.
 *  @param f [read/write] prediction vector. 
 *  @param l [write] partial derivative of loss function w.r.t. f
 */
void CHuberHingeLoss::LossAndGrad(double& loss, TheMatrix& f, TheMatrix& l)
{
   f.ElementWiseMult(_data->labels());
   double* yf = f.Data();
   double* Y = _data->labels().Data();
   int len = f.Length();
   loss = 0.0;
   l.Zero();

   for(int i=0; i < len; i++) 
   {
      double v = 1-yf[i];
      if(h < v)
      {
         loss += v;
         l.Set(i,-Y[i]);
      }
      else if(-h > v) {}
      else
      {
         loss += (v+h)*(v+h)/4/h;
         l.Set(i, -Y[i]*(v+h)/2/h);
      }
   }
}
开发者ID:funkey,项目名称:bmrm,代码行数:35,代码来源:huberhingeloss.cpp

示例3: Loss

/**  
 *  Compute hinge loss. CAUTION: f is passed by reference and is
 *  changed within this function. This is done for efficiency reasons,
 *  otherwise we would have had to create a new copy of f. 
 *   
 *  @param loss [write] loss value computed.
 *  @param f [read/write] prediction vector. 
 */
void CLogisticLoss::Loss(double& loss, TheMatrix& f)
{
	loss = 0;
	f.ElementWiseMult(_data->labels());  // f = y*f
	double* f_array = f.Data();  // pointer to memory location of f (faster element access)
	int len = f.Length();
	for(int i=0; i < len; i++)
    {
		if(fabs(f_array[i]) == 0.0)
            loss += LN2;
        else if (f_array[i] > 0.0)
            loss += log(1+exp(-f_array[i]));
        else
            loss += log(1+exp(f_array[i])) - f_array[i];
    }
}
开发者ID:funkey,项目名称:bmrm,代码行数:24,代码来源:logisticloss.cpp


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