source: trunk/lib/svm/Kernel_MEV.h @ 336

// $Id: Kernel_MEV.h 336 2005-06-03 14:16:19Z peter $

#ifndef _theplu_svm_kernel_mev_
#define _theplu_svm_kernel_mev_

#include <c++_tools/svm/Kernel.h>
#include <c++_tools/svm/KernelFunction.h>
#include <c++_tools/gslapi/matrix.h>

namespace theplu {
namespace svm {

  ///
  ///   @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 Kernel_SEV
  ///
  class Kernel_MEV : public Kernel 
  {
    
  public:
    
    ///
    ///  Default constructor (not implemented)
    ///
    Kernel_MEV();

    ///
    ///   Constructor taking the data matrix and KernelFunction as
    ///   input.Each column in the data matrix corresponds to one
    ///   sample. @note Can not handle NaNs. 
    ///
    Kernel_MEV(const gslapi::matrix&, const KernelFunction&);
    
    ///
    ///   @todo
    ///   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.
    Kernel_MEV(const gslapi::matrix& data, const KernelFunction&, 
               const gslapi::matrix& weight);

    ///
    /// Copy constructor (not implemented)
    ///
    Kernel_MEV(const Kernel_MEV&);

    ///
    ///   Destructor
    ///
    virtual ~Kernel_MEV(void);

    ///
    /// @return element at position (\a row, \a column) of the Kernel
    /// matrix
    ///
    double operator()(const size_t row,const size_t column) const 
    { return (*kf_)(data_.TEMP_col_return(row),data_.TEMP_col_return(column)); }

    ///
    /// @brief number of samples
    ///
    inline size_t size(void) const { return data_.columns(); } 

  private:
    const gslapi::matrix& data_;
    const KernelFunction* kf_;

  }; // class Kernel_MEV

}} // of namespace svm and namespace theplu

#endif