mlpack  1.0.12
cosine_tree.hpp
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1 
15 #ifndef __MLPACK_CORE_TREE_COSINE_TREE_COSINE_TREE_HPP
16 #define __MLPACK_CORE_TREE_COSINE_TREE_COSINE_TREE_HPP
17 
18 #include <mlpack/core.hpp>
19 #include <boost/heap/priority_queue.hpp>
20 
21 namespace mlpack {
22 namespace tree {
23 
24 // Predeclare classes for CosineNodeQueue typedef.
25 class CompareCosineNode;
26 class CosineTree;
27 
28 // CosineNodeQueue typedef.
29 typedef boost::heap::priority_queue<CosineTree*,
30  boost::heap::compare<CompareCosineNode> > CosineNodeQueue;
31 
32 class CosineTree
33 {
34  public:
35 
44  CosineTree(const arma::mat& dataset);
45 
55  CosineTree(CosineTree& parentNode, const std::vector<size_t>& subIndices);
56 
71  CosineTree(const arma::mat& dataset,
72  const double epsilon,
73  const double delta);
74 
79  ~CosineTree();
80 
90  void ModifiedGramSchmidt(CosineNodeQueue& treeQueue,
91  arma::vec& centroid,
92  arma::vec& newBasisVector,
93  arma::vec* addBasisVector = NULL);
94 
107  double MonteCarloError(CosineTree* node,
108  CosineNodeQueue& treeQueue,
109  arma::vec* addBasisVector1 = NULL,
110  arma::vec* addBasisVector2 = NULL);
111 
117  void ConstructBasis(CosineNodeQueue& treeQueue);
118 
124  void CosineNodeSplit();
125 
132  void ColumnSamplesLS(std::vector<size_t>& sampledIndices,
133  arma::vec& probabilities, size_t numSamples);
134 
141  size_t ColumnSampleLS();
142 
155  size_t BinarySearch(arma::vec& cDistribution, double value, size_t start,
156  size_t end);
157 
165  void CalculateCosines(arma::vec& cosines);
166 
171  void CalculateCentroid();
172 
174  void GetFinalBasis(arma::mat& finalBasis) { finalBasis = basis; }
175 
177  const arma::mat& GetDataset() const { return dataset; }
178 
180  std::vector<size_t>& VectorIndices() { return indices; }
181 
183  void L2Error(const double error) { this->l2Error = error; }
184 
186  double L2Error() const { return l2Error; }
187 
189  arma::vec& Centroid() { return centroid; }
190 
192  void BasisVector(arma::vec& bVector) { this->basisVector = bVector; }
193 
195  arma::vec& BasisVector() { return basisVector; }
196 
198  CosineTree* Left() { return left; }
199 
201  CosineTree* Right() { return right; }
202 
204  size_t NumColumns() const { return numColumns; }
205 
207  double FrobNormSquared() const { return frobNormSquared; }
208 
210  size_t SplitPointIndex() const { return indices[splitPointIndex]; }
211 
212  private:
214  const arma::mat& dataset;
216  double epsilon;
218  double delta;
220  arma::mat basis;
222  CosineTree* parent;
224  CosineTree* left;
226  CosineTree* right;
228  std::vector<size_t> indices;
230  arma::vec l2NormsSquared;
232  arma::vec centroid;
234  arma::vec basisVector;
238  size_t numColumns;
240  double l2Error;
243 };
244 
246 {
247  public:
248 
249  // Comparison function for construction of priority queue.
250  bool operator() (const CosineTree* a, const CosineTree* b) const
251  {
252  return a->L2Error() < b->L2Error();
253  }
254 };
255 
256 }; // namespace tree
257 }; // namespace mlpack
258 
259 #endif
void CalculateCosines(arma::vec &cosines)
Calculate cosines of the columns present in the node, with respect to the sampled splitting point...
CosineTree * left
Left child of the node.
std::vector< size_t > indices
Indices of columns of input matrix in the node.
Linear algebra utility functions, generally performed on matrices or vectors.
Definition: load.hpp:23
size_t numColumns
Number of columns of input matrix in the node.
arma::vec l2NormsSquared
L2-norm squared of columns in the node.
size_t SplitPointIndex() const
Get the column index of split point of the node.
double FrobNormSquared() const
Get the Frobenius norm squared of columns in the node.
void CosineNodeSplit()
This function splits the cosine node into two children based on the cosines of the columns contained ...
double MonteCarloError(CosineTree *node, CosineNodeQueue &treeQueue, arma::vec *addBasisVector1=NULL, arma::vec *addBasisVector2=NULL)
Estimates the squared error of the projection of the input node's matrix onto the current vector subs...
size_t splitPointIndex
Index of split point of cosine node.
void GetFinalBasis(arma::mat &finalBasis)
Returns the basis of the constructed subspace.
size_t ColumnSampleLS()
Sample a point from the Length-Squared distribution of the cosine node.
arma::vec centroid
Centroid of columns of input matrix in the node.
const arma::mat & dataset
Matrix for which cosine tree is constructed.
arma::vec & Centroid()
Get pointer to the centroid vector.
void ConstructBasis(CosineNodeQueue &treeQueue)
Constructs the final basis matrix, after the cosine tree construction.
~CosineTree()
Destroy the cosine tree and all of its children (take care of the memory allocations too)...
double epsilon
Error tolerance fraction for calculated subspace.
bool operator()(const CosineTree *a, const CosineTree *b) const
CosineTree * Left()
Get pointer to the left child of the node.
CosineTree(const arma::mat &dataset)
CosineTree constructor for the root node of the tree.
void BasisVector(arma::vec &bVector)
Set the basis vector of the node.
size_t BinarySearch(arma::vec &cDistribution, double value, size_t start, size_t end)
Sample a column based on the cumulative Length-Squared distribution of the cosine node...
arma::vec & BasisVector()
Get the basis vector of the node.
void CalculateCentroid()
Calculate centroid of the columns present in the node.
CosineTree * parent
Parent of the node.
arma::vec basisVector
Orthonormalized basis vector of the node.
CosineTree * right
Right child of the node.
double L2Error() const
Get the Monte Carlo error.
size_t NumColumns() const
Get number of columns of input matrix in the node.
CosineTree * Right()
Get pointer to the right child of the node.
void ModifiedGramSchmidt(CosineNodeQueue &treeQueue, arma::vec &centroid, arma::vec &newBasisVector, arma::vec *addBasisVector=NULL)
Calculates the orthonormalization of the passed centroid, with respect to the current vector subspace...
boost::heap::priority_queue< CosineTree *, boost::heap::compare< CompareCosineNode > > CosineNodeQueue
Definition: cosine_tree.hpp:26
double l2Error
Monte Carlo error for this node.
arma::mat basis
Subspace basis of the input dataset.
double frobNormSquared
Frobenius norm squared of columns in the node.
void ColumnSamplesLS(std::vector< size_t > &sampledIndices, arma::vec &probabilities, size_t numSamples)
Sample 'numSamples' points from the Length-Squared distribution of the cosine node.
void L2Error(const double error)
Set the Monte Carlo error.
const arma::mat & GetDataset() const
Get pointer to the dataset matrix.
std::vector< size_t > & VectorIndices()
Get the indices of columns in the node.
double delta
Cumulative probability for Monte Carlo error lower bound.