text: /*
   *  tsne.h
   *  Header file for t-SNE.
   *
   *  Created by Laurens van der Maaten.
   *  Copyright 2012, Delft University of Technology. All rights reserved.
   *
   */
  
  
  #ifndef TSNE_H
  #define TSNE_H
  
  #include "vptree.h"
  
  static inline double sign(double x) { return (x == .0 ? .0 : (x < .0 ? -1.0 : 1.0)); }
  
  class TSNE
  {    
  public:
    void run(double* X, int N, int D, double* Y, int no_dims, double perplexity, double theta, double (*metrics)(const DataPoint&, const DataPoint&));
    bool load_data(double** data, int* n, int* d, double* theta, double* perplexity);
    void save_data(double* data, int* landmarks, double* costs, int n, int d);
    void symmetrizeMatrix(int** row_P, int** col_P, double** val_P, int N); // should be static?!
  
      
  private:
    void computeGradient(double* P, int* inp_row_P, int* inp_col_P, double* inp_val_P, double* Y, int N, int D, double* dC, double theta);
    void computeExactGradient(double* P, double* Y, int N, int D, double* dC);
    double evaluateError(double* P, double* Y, int N);
    double evaluateError(int* row_P, int* col_P, double* val_P, double* Y, int N, double theta);
    void zeroMean(double* X, int N, int D);
    void computeGaussianPerplexity(double* X, int N, int D, double* P, double perplexity, double (*metrics)(const DataPoint&, const DataPoint&));
    void computeGaussianPerplexity(double* X, int N, int D, int** _row_P, int** _col_P, double** _val_P, double perplexity, int K, double (*metrics)(const DataPoint&, const DataPoint&));
    void computeSquaredEuclideanDistance(double* X, int N, int D, double* DD);
    double randn();
  };
  
  #endif
  
  