cosine_tree.h

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/* MLPACK 0.2
 *
 * Copyright (c) 2008, 2009 Alexander Gray,
 *                          Garry Boyer,
 *                          Ryan Riegel,
 *                          Nikolaos Vasiloglou,
 *                          Dongryeol Lee,
 *                          Chip Mappus, 
 *                          Nishant Mehta,
 *                          Hua Ouyang,
 *                          Parikshit Ram,
 *                          Long Tran,
 *                          Wee Chin Wong
 *
 * Copyright (c) 2008, 2009 Georgia Institute of Technology
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 */
#ifndef QUICSVD_COSINE_TREE_H
#define QUICSVD_COSINE_TREE_H
#include <fastlib/fastlib.h>

class CosineNode {
  Matrix A_;

  ArrayList<int> origIndices_;

  ArrayList<double> norms_;

  ArrayList<double> cum_norms_;

  Vector mean_;

  bool isLeft_;

  double L2Err_;

  CosineNode *parent_, *left_, *right_;

 public:
  CosineNode(const Matrix& A);

  CosineNode(CosineNode& parent, const ArrayList<int>& indices,
             bool isLeft);

  void GetColumn(int i_col, Vector* col) {
    A_.MakeColumnVector(origIndices_[i_col], col);
  }

  index_t n_cols() const {
    return origIndices_.size();
  }

  void Split();
  
  double getSumL2() const {
    return cum_norms_[n_cols()-1];
  }

  const Vector& getMean() const {
    return mean_;
  }

  index_t getOrigIndex(index_t i_col) const {
    return origIndices_[i_col];
  }

  void setL2Err(double L2Err) {
    L2Err_ = L2Err;
  }

  bool hasLeft() const {
    return left_ != NULL;
  }

  bool hasRight() const {
    return right_ != NULL;
  }

  CosineNode* getLeft() {
    return left_;
  }

  CosineNode* getRight() {
    return right_;
  }

 private:
  // Helper functions

  void CalStats();

  void ChooseCenter(Vector* center);

  void CalCosines(const Vector& center, ArrayList<double>* cosines);

  void CreateIndices(ArrayList<int>* indices);

  friend class CosineNodeTest;

  friend class CompareCosineNode;
};

class CompareCosineNode {
 public:
  bool operator ()(CosineNode* a, CosineNode* b) {
    return a->L2Err_ < b->L2Err_;
  }
};

class CosineNodeTest {
  FILE * logfile;

  void test_CosineTreeNode() {
    Matrix A;
    data::Load("input.txt", &A);
    CosineNode root(A);
    //ot::Print(root, "cosine root", logfile);

    root.Split();

    //ot::Print(*root.left_, "left node", logfile);
    //ot::Print(*root.right_, "right node", logfile);
  }

public:
  CosineNodeTest() {
    logfile = fopen("LOG", "w");
  }
  ~CosineNodeTest() {
    fclose(logfile);
  }

  void run_tests() {
    test_CosineTreeNode();
  }
};


#endif