ReconstructionWeightsKernel.h

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// -*- C++ -*-

// ReconstructionWeightsKernel.h
//
// Copyright (C) 2004 Olivier Delalleau 
// 
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
// 
//  1. Redistributions of source code must retain the above copyright
//     notice, this list of conditions and the following disclaimer.
// 
//  2. Redistributions in binary form must reproduce the above copyright
//     notice, this list of conditions and the following disclaimer in the
//     documentation and/or other materials provided with the distribution.
// 
//  3. The name of the authors may not be used to endorse or promote
//     products derived from this software without specific prior written
//     permission.
// 
// THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
// IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
// OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
// NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
// TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// 
// This file is part of the PLearn library. For more information on the PLearn
// library, go to the PLearn Web site at www.plearn.org

/* *******************************************************      
   * $Id: ReconstructionWeightsKernel.h,v 1.6 2004/07/21 16:30:52 chrish42 Exp $ 
   ******************************************************* */

// Authors: Olivier Delalleau

#ifndef ReconstructionWeightsKernel_INC
#define ReconstructionWeightsKernel_INC

#include "Kernel.h"
#include <plearn/vmat/SelectRowsVMatrix.h>
#include <plearn/vmat/ShiftAndRescaleVMatrix.h>

namespace PLearn {
using namespace std;

class ReconstructionWeightsKernel: public Kernel
{

private:

  typedef Kernel inherited;

  bool build_in_progress;

  mutable bool new_data;

  mutable Mat k_xi_x_sorted;

  mutable TVec<int> neighbors_of_x;

  mutable Vec weights_x;

  mutable Mat local_gram;
  
  mutable PP<ShiftAndRescaleVMatrix> centered_neighborhood;

  mutable Vec ones;

protected:

  // *********************
  // * Protected options *
  // *********************

  // Fields below are not options.

  Ker dist_ker;

  Ker dp_ker;
    
  TMat<int> neighbors;

  TVec< TMat<int> > is_neighbor_of;

  PP<SelectRowsVMatrix> sub_data;

  Mat weights;

public:

  // ************************
  // * Public build options *
  // ************************

  Ker distance_kernel;
  Ker dot_product_kernel;
  int ignore_nearest;
  int knn;
  real regularizer;

  // ****************
  // * Constructors *
  // ****************

  ReconstructionWeightsKernel();

  // ******************
  // * Kernel methods *
  // ******************

private: 

  void build_();

protected: 
  
  static void declareOptions(OptionList& ol);

public:

  // ************************
  // **** Object methods ****
  // ************************

  virtual void build();

  virtual void makeDeepCopyFromShallowCopy(map<const void*, void*>& copies);

  // Declares other standard object methods.
  PLEARN_DECLARE_OBJECT(ReconstructionWeightsKernel);

  // **************************
  // **** Kernel methods ****
  // **************************

  virtual real evaluate(const Vec& x1, const Vec& x2) const;

  virtual real evaluate_i_j(int i, int j) const;

  virtual real evaluate_i_x(int i, const Vec& x, real squared_norm_of_x=-1) const;

  virtual real evaluate_x_i(const Vec& x, int i, real squared_norm_of_x=-1) const;

  virtual real evaluate_x_i_again(const Vec& x, int i, real squared_norm_of_x=-1, bool first_time = false) const;

  virtual void setDataForKernelMatrix(VMat the_data);

  virtual real evaluate_sum_k_i_k_j(int i, int j) const;

  virtual void computeLLEMatrix(const Mat& lle_mat) const;

  // *** SUBCLASS WRITING: ***
  // While in general not necessary, in case of particular needs 
  // (efficiency concerns for ex) you may also want to overload
  // some of the following methods:
  // virtual real evaluate_i_x_again(int i, const Vec& x, real squared_norm_of_x=-1, bool first_time = false) const;
  // virtual void computeGramMatrix(Mat K) const;
  // virtual void addDataForKernelMatrix(const Vec& newRow);
  // virtual void setParameters(Vec paramvec);
  // virtual Vec getParameters() const;

protected:

  void computeWeights();
  
  void reconstruct(const Vec& x, const TVec<int>& neighbors, Vec& w) const;

};

// Declares a few other classes and functions related to this class.
DECLARE_OBJECT_PTR(ReconstructionWeightsKernel);
  
} // end of namespace PLearn

#endif

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