source: trunk/lib/svm/Kernel.h @ 333

// $Id: Kernel.h 333 2005-06-02 13:34:08Z jari $

#ifndef _theplu_svm_kernel
#define _theplu_svm_kernel

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

namespace theplu {
namespace svm {

  class KernelFunction;

  ///
  ///   @brief Base Class for Kernels. 
  ///
  ///   Class taking care of the \f$NxN\f$ kernel matrix, where
  ///   \f$N\f$ is number of samples. Each element in the Kernel
  ///   matrix is the scalar product of the corresponding pair of
  ///   samples. Type of Kernel is defined by a KernelFunction.
  ///   
  ///   @note If the KernelFunction is destroyed, the Kernel is no
  ///   longer defined.
  ///
  class Kernel
  {
    
  public:

    ///
    /// Default constructor
    ///
    Kernel(void);

    ///
    /// Copy constructor
    ///
    /// @note SHALLOW copy performed.
    ///
    Kernel(const Kernel&);

    ///
    ///   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(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(const gslapi::matrix& data, const KernelFunction&, 
               const gslapi::matrix& weight);

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

    ///
    /// @return element at position (\a row, \a column) of the Kernel
    /// matrix
    ///
    virtual double operator()(const size_t row,const size_t column) const=0;

    ///
    /// @brief number of samples
    ///
    virtual size_t size(void) const; 
    
  protected:
    const gslapi::matrix& data_;
    const KernelFunction* kf_;

    virtual bool is_view(void) const;

  }; // class Kernel

}} // of namespace svm and namespace theplu

#endif