/** 
 * @file AlgebraTools.h
 * @brief Algebra Tools
 * @author Michael Koch,Erik Rodner
 * @date 05/20/2009

 */
#ifndef AlgebraToolsINCLUDE
#define AlgebraToolsINCLUDE

#include <vislearning/nice_nonvis.h>

namespace OBJREC 
{

class AlgebraTools
{
     public:
     //FIXME: find a better place
     template<typename T>
		static T sign(T n);
          
     static void calculateMean(const NICE::Matrix &data, NICE::Vector &mean);
     static void calculateMean(const NICE::Matrix &data,NICE::Vector &mean,NICE::Vector &sigma);
     static void orthogonalize(NICE::Matrix &M,bool iterative=true);
     static double trace(const NICE::Matrix &M);
     static double matrixRowColNorm(const NICE::Matrix &M);
     static NICE::Matrix vectorToMatrix(const NICE::Vector &vec);
     static NICE::Vector matrixToVector(const NICE::Matrix &mat);
      /**
      * Converting Vector to diagonal Matrix
      * @param diagonalelements diagonal elements
      * @return Matrix with diagonal elements
       */
     static NICE::Matrix diag(const NICE::Vector &diagonalelements);
     static double meanOfVector(const NICE::Vector &vec);
     static NICE::Vector meanOfMatrix(const NICE::Matrix &M);
};

template<typename T>
	T AlgebraTools::sign(T n)
{
     if (n < 0) return -1;
     if (n > 0) return 1;
     return 0;
}

}

#endif