source: trunk/lib/svm/KernelView.h @ 330

// $Id: KernelView.h 330 2005-06-01 21:30:47Z peter $

#ifndef _theplu_svm_kernel_view_
#define _theplu_svm_kernel_view_

#include <c++_tools/svm/Kernel.h>
#include <vector>

namespace theplu {
namespace svm {

  class KernelFunction;

  ///
  ///   @brief View into sub Kernel
  ///   When training 
  ///
  class KernelView : public Kernel 
  {
    
  public:
    
    ///
    /// Contructor taking the Kernel to view into and a vector of the
    /// indeces we view into. If Kernel is a KernelView it implemented
    /// to view into something that is viewing into... and may
    /// therefore be slow. Use instead the original Kernel and view
    /// directly into that.
    ///
    KernelView(const Kernel&, const std::vector<size_t>&);
    
    ///
    /// @todo
    /// Copy constructor
    ///
    KernelView(const KernelView&);

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

    ///
    /// @return element at position (\a row, \a column) in the Kernel
    /// matrix
    ///
    inline double operator()(const size_t row,const size_t column) const
    { return (*kernel_)(index[row],index[column]); }
    
  private:
    const Kernel* kernel_;
    const std::vector<size_t>& index_;


    inline bool is_view(void) const { return true; }

  }; // class KernelView

}} // of namespace svm and namespace theplu

#endif