source: trunk/lib/classifier/KernelWeighted_MEV.h @ 542

// $Id: KernelWeighted_MEV.h 542 2006-03-05 15:46:47Z peter $

#ifndef _theplu_classifier_kernel_weighted_mev_
#define _theplu_classifier_kernel_weighted_mev_

#include <c++_tools/classifier/Kernel.h>

#include <c++_tools/classifier/DataLookup1D.h>
#include <c++_tools/classifier/KernelFunction.h>
#include <c++_tools/classifier/MatrixLookup.h>
//#include <c++_tools/gslapi/matrix.h>

namespace theplu {
namespace classifier {

  ///
  ///   @brief Memory Efficient Kernel
  ///   Class taking care of the \f$NxN\f$ kernel matrix, where
  ///   \f$N\f$ is number of samples. Type of Kernel is defined by a
  ///   KernelFunction. This Memory Efficient Version (MEV) does not
  ///   store the kernel matrix in memory, but calculates each element
  ///   when it is needed. When memory allows do always use Kernel_SEV
  ///   instead.
  ///   
  ///   @see also KernelWeighted_SEV
  ///
  class KernelWeighted_MEV : public Kernel 
  {
    
  public:
    
    ///
    ///   Constructor taking the \a data matrix, the KernelFunction and a
    ///   \a weight matrix as input. Each column in the data matrix
    ///   corresponds to one sample.
    ///
    /// @note if @a data, @a kf, or @a weights is destroyed the
    /// behaviour of the object is undefined
    ///
    inline KernelWeighted_MEV(const MatrixLookup& data, 
                              const KernelFunction& kf, 
                              const MatrixLookup& weights)
    : Kernel(data,kf), weights_(weights) {}

    ///
    /// @return Element at position (\a row, \a column) of the Kernel
    /// matrix
    ///
    double operator()(const size_t row, const size_t column) const;

    ///
    /// @return kernel element between data @a ve and training sample @a i
    /// 
    inline double element(const DataLookup1D& vec, const size_t i) const
    { 
      return (*kf_)(vec, DataLookup1D(data_,i), 
                    DataLookup1D(vec.size(),1.0),
                    DataLookup1D(weights_,i)); 
    }

    inline double element(const DataLookup1D& vec, const DataLookup1D& w, 
                          const size_t i) const
    { 
      return (*kf_)(vec, DataLookup1D(data_,i),w,DataLookup1D(weights_,i)); 
    }

  private:
    ///
    /// Copy constructor (not implemented)
    ///
    KernelWeighted_MEV(const KernelWeighted_MEV&);

    const MatrixLookup& weights_;

  };

}} // of namespace classifier and namespace theplu

#endif