EST_PST.h

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/*                                                                       */
/*                Centre for Speech Technology Research                  */
/*                     University of Edinburgh, UK                       */
/*                         Copyright (c) 1996                            */
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/*************************************************************************/
/*                     Author :  Alan W Black                            */
/*                     Date   :  July 1996                               */
/*-----------------------------------------------------------------------*/
/*                                                                       */
/*             A general class for PredictionSuffixTrees                 */
/*                                                                       */
/*=======================================================================*/

#ifndef __PredictionSuffixTree_H__
#define __PredictionSuffixTree_H__

#include "EST_simplestats.h"
#include "EST_types.h"
#include "EST_Features.h"

class EST_PredictionSuffixTree_tree_node {
private:
    
protected:
    
    int p_level;
    int state;
    EST_DiscreteProbDistribution pd;
    EST_String path;  /* context */
    void delete_node(void *n) { if (n != 0) delete (EST_PredictionSuffixTree_tree_node *)n;}

public:

//    EST_StringTrie nodes;
//    EST_TKVL <EST_String, EST_PredictionSuffixTree_tree_node *> nodes;
    EST_Features nodes;
    EST_PredictionSuffixTree_tree_node() {p_level=0; state=0;}
    ~EST_PredictionSuffixTree_tree_node();
    void clear(void);
    const EST_String &get_path(void) const {return path;}
    void set_path(const EST_String &s) {path=s;}
    void set_level(int l) {p_level=l;}
    void set_state(int s) {state=s;}
    int get_state(void) const {return state;}
    int get_level(void) const {return p_level;}
    void cumulate(const EST_String &s,double count=1) {pd.cumulate(s,count);}
    void cumulate(const int i,double count=1) {pd.cumulate(i,count);}
    const EST_String &most_probable(double *p) const;
    const EST_DiscreteProbDistribution &prob_dist() const {return pd;}
    void print_freqs(ostream &os);
    void print_probs(ostream &os);
};

VAL_REGISTER_CLASS_DCLS(pstnode,EST_PredictionSuffixTree_tree_node)

class EST_PredictionSuffixTree {
    
private:
    
    enum EST_filetype {PredictionSuffixTree_ascii, PredictionSuffixTree_binary};

protected:

    int p_order;
    int num_states;
    EST_PredictionSuffixTree_tree_node *nodes;
    EST_DiscreteProbDistribution *pd; // distribution of predictees
    const EST_String &ppredict(EST_PredictionSuffixTree_tree_node *node,
                   const EST_StrVector &words,
                   double *prob, int *state,
                   const int index=0) const;

    void p_accumulate(EST_PredictionSuffixTree_tree_node *node,
              const EST_StrVector &words,
              double count, 
              const int index=0);

    const EST_DiscreteProbDistribution &p_prob_dist(
    EST_PredictionSuffixTree_tree_node *node, 
    const EST_StrVector &words,
    const int index=0) const;
public:
    EST_PredictionSuffixTree();
    EST_PredictionSuffixTree(const int order) {init(order);}
    EST_PredictionSuffixTree(const EST_String filename);
    EST_PredictionSuffixTree(const EST_TList<EST_String> &vocab,int order=2);
    ~EST_PredictionSuffixTree(); 
    void clear(void);
    void init(const int order);
    double samples() const { return pd->samples(); }
    int states() const { return num_states; }
    int order(void) const {return p_order;}
    void accumulate(const EST_StrVector &words,const double count=1,const int index=0);

    int load(const EST_String filename);
    int save(const EST_String filename,const EST_PredictionSuffixTree::EST_filetype type=PredictionSuffixTree_ascii);

    // build EST_PredictionSuffixTree from train data
    void build(const EST_String filename,
           const EST_String prev,
           const EST_String prev_prev,
           const EST_String last);

    void build(const EST_StrList &input); // to go

    void test(const EST_String filename);   // test EST_PredictionSuffixTree against test data
    void print_freqs(ostream &os);
    void print_probs(ostream &os);

    const EST_String &predict(const EST_StrVector &words) const;
    const EST_String &predict(const EST_StrVector &words,double *prob) const;
    const EST_String &predict(const EST_StrVector &words,double *prob,int *state) const;
    const EST_DiscreteProbDistribution &prob_dist(const EST_StrVector &words)
    const 
    {return p_prob_dist(nodes,words);}
    /* Reverse probability, given X what is prob of EST_PredictionSuffixTree Y */
    double rev_prob(const EST_StrVector &words) const;
    double rev_prob(const EST_StrVector &words,
            const EST_DiscreteProbDistribution &pd) const;
    /* print frequency or probability models */
    /* build model from file */
    /* predict and measure success */

};

#endif // __PredictionSuffixTree_H__