text: /*
  Copyright (c) by respective owners including Yahoo!, Microsoft, and
  individual contributors. All rights reserved.  Released under a BSD
  license as described in the file LICENSE.
   */
  #pragma once
  #include <string>
  #include "parse_primitives.h"
  
  struct shared_data;
  struct vw;
  
  class loss_function {
  
  public :
  	/*
  	 * getLoss evaluates the example loss.
  	 * The function returns the loss value
  	 */
  	//virtual float getLoss(example *&ec, gd_vars &vars) = 0;
    virtual float getLoss(shared_data*, float prediction, float label) = 0;
  
  	/*
  	 * getUpdate evaluates the update scalar
  	 * The function return the update scalar
  	 */
  	virtual float getUpdate(float prediction, float label, float eta_t, float norm) = 0;
  	virtual float getUnsafeUpdate(float prediction, float label, float eta_t, float norm) = 0;
  	virtual float getRevertingWeight(shared_data*, float prediction, float eta_t) = 0;
  	virtual float getSquareGrad(float prediction, float label) = 0;
  	virtual float first_derivative(shared_data*, float prediction, float label) = 0;
  	virtual float second_derivative(shared_data*, float prediction, float label) = 0;
  	virtual ~loss_function() {};
  };
  
  loss_function* getLossFunction(vw&, std::string funcName, float function_parameter = 0);
  