EST_SCFG.cc

/*************************************************************************/
/*                                                                       */
/*                Centre for Speech Technology Research                  */
/*                     University of Edinburgh, UK                       */
/*                         Copyright (c) 1997                            */
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/*************************************************************************/
/*                     Author :  Alan W Black                            */
/*                     Date   :  October 1997                            */
/*-----------------------------------------------------------------------*/
/*                                                                       */
/* A class for representing Stochastic Context Free Grammars             */
/*                                                                       */
/*=======================================================================*/
#include <iostream>
#include "EST_Pathname.h"
#include "EST_SCFG.h"

EST_SCFG_Rule::EST_SCFG_Rule(double prob,int p, int m)
{ 
    set_rule(prob,p,m); 
}

EST_SCFG_Rule::EST_SCFG_Rule(double prob,int p, int q, int r)
{ 
    set_rule(prob,p,q,r); 
}

void EST_SCFG_Rule::set_rule(double prob,int p, int m)
{
    p_prob = prob;
    p_mother = p;
    p_daughter1 = m;
    p_type = est_scfg_unary_rule;
}

void EST_SCFG_Rule::set_rule(double prob,int p, int q, int r)
{
    p_prob = prob;
    p_mother = p;
    p_daughter1 = q;
    p_daughter2 = r;
    p_type = est_scfg_binary_rule;
}

EST_SCFG::EST_SCFG()
{
    p_prob_B=0;
    p_prob_U=0;
}

EST_SCFG::EST_SCFG(LISP rs)
{
    p_prob_B=0;
    p_prob_U=0;
    set_rules(rs);
}

EST_SCFG::~EST_SCFG(void)
{

    delete_rule_prob_cache();

}

void EST_SCFG::find_terms_nonterms(EST_StrList &nt, EST_StrList &t,LISP rs)
{
    // Cummulate the nonterminals and terminals
    LISP r;

    for (r=rs; r != NIL; r=cdr(r))
    {
    LISP p = car(cdr(car(r)));
    if (!strlist_member(nt,get_c_string(p)))
        nt.append(get_c_string(p));
    if (siod_llength(car(r)) == 3)   // unary rule
    {
        LISP d = car(cdr(cdr(car(r))));
        if (!strlist_member(t,get_c_string(d)))
        t.append(get_c_string(d));
    }
    else                            // binary rules
    {
        LISP d1 = car(cdr(cdr(car(r))));
        LISP d2 = car(cdr(cdr(cdr(car(r)))));
        if (!strlist_member(nt,get_c_string(d1)))
        nt.append(get_c_string(d1));
        if (!strlist_member(nt,get_c_string(d2)))
        nt.append(get_c_string(d2));
    }
    }

}

void EST_SCFG::set_rules(LISP lrules)
{
    // Initialise rule base from Lisp form
    LISP r;
    EST_StrList nt_list, term_list;

    rules.clear();
    delete_rule_prob_cache();

    find_terms_nonterms(nt_list,term_list,lrules);
    nonterminals.init(nt_list);
    terminals.init(term_list);

    if (!consp(car(cdr(car(lrules)))))
    p_distinguished_symbol = 
        nonterminal(get_c_string(car(cdr(car(lrules)))));
    else
    cerr << "SCFG: no distinguished symbol" << endl;

    for (r=lrules; r != NIL; r=cdr(r))
    {
    if ((siod_llength(car(r)) < 3) ||
        (siod_llength(car(r)) > 4) ||
        (!numberp(car(car(r)))))
        cerr << "SCFG rule is malformed" << endl;
//      est_error("SCFG rule is malformed\n");
    else
    {
        EST_SCFG_Rule rule;
        if (siod_llength(car(r)) == 3)
        {
        int m = nonterminal(get_c_string(car(cdr(car(r)))));
        int d = terminal(get_c_string(car(cdr(cdr(car(r))))));
        rule.set_rule(get_c_float(car(car(r))),m,d);
        }
        else
        {
        int p = nonterminal(get_c_string(car(cdr(car(r)))));
        int d1=nonterminal(get_c_string(car(cdr(cdr(car(r))))));
        int d2 = nonterminal(get_c_string(car(cdr(cdr(cdr(car(r)))))));
        rule.set_rule(get_c_float(car(car(r))),p,d1,d2);
        }
        rules.append(rule);
    }
    }

    rule_prob_cache();
}

LISP EST_SCFG::get_rules()
{
    // Return LISP form of rules
    EST_Litem *p;
    LISP r;

    for (r=NIL,p=rules.head(); p != 0; p=p->next())
    {
    if (rules(p).type() == est_scfg_unary_rule)
        r = cons(cons(flocons(rules(p).prob()),
              cons(rintern(nonterminal(rules(p).mother())),
                   cons(rintern(terminal(rules(p).daughter1())),NIL))),
             r);
    else if (rules(p).type() == est_scfg_binary_rule)
        r = cons(cons(flocons(rules(p).prob()),
             cons(rintern(nonterminal(rules(p).mother())),
              cons(rintern(nonterminal(rules(p).daughter1())),
               cons(rintern(nonterminal(rules(p).daughter2())),
                NIL)))),
             r);
    }
    return reverse(r);
}

EST_read_status EST_SCFG::load(const EST_String &filename)
{
    LISP rs;

    rs = vload(filename,1);

    set_rules(rs);

    return format_ok;
}

EST_write_status EST_SCFG::save(const EST_String &filename)
{
    EST_Pathname outfile(filename);
    FILE *fd;
    LISP r;

    if (outfile == "-")
    fd = stdout;
    else
    {
    if ((fd=fopen(outfile,"w")) == NULL)
    {
        cerr << "scfg_train: failed to open file \"" << outfile << 
        "\" for writing" << endl;
        return misc_write_error;
    }
    }
    
    for (r=get_rules(); r != NIL; r=cdr(r))
    pprint_to_fd(fd,car(r));
    
    if (fd != stdout)
    fclose(fd);

    return write_ok;
}


void EST_SCFG::rule_prob_cache()
{
    // Build access cache for the probabilities of binary rules
    // This will have to made much more efficient
    int i,j;

    p_prob_B = new double**[num_nonterminals()];
    p_prob_U = new double*[num_nonterminals()];
    for (i=0; i < num_nonterminals(); i++)
    {
    p_prob_B[i] = new double*[num_nonterminals()];
    p_prob_U[i] = new double[num_terminals()];
    memset(p_prob_U[i],0,sizeof(double)*num_terminals());
    for (j=0; j < num_nonterminals(); j++)
    {
        p_prob_B[i][j] = new double[num_nonterminals()];
        memset(p_prob_B[i][j],0,sizeof(double)*num_nonterminals());
    }
    }

    set_rule_prob_cache();

}

void EST_SCFG::set_rule_prob_cache()
{
    EST_Litem *pp;

    for (pp=rules.head(); pp != 0; pp = pp->next())
    {
    if (rules(pp).type() == est_scfg_binary_rule)
    {
        int p = rules(pp).mother();
        int q = rules(pp).daughter1();
        int r = rules(pp).daughter2();
        p_prob_B[p][q][r] = rules(pp).prob();
    }
    else if (rules(pp).type() == est_scfg_unary_rule)
    {
        int p = rules(pp).mother();
        int m = rules(pp).daughter1();
        p_prob_U[p][m] = rules(pp).prob();
    }
    }
}

void EST_SCFG::delete_rule_prob_cache()
{
    int i,j;

    if (p_prob_B == 0)
    return;

    for (i=0; i < num_nonterminals(); i++)
    {
    for (j=0; j < num_nonterminals(); j++)
        delete [] p_prob_B[i][j];
    delete [] p_prob_B[i];
    delete [] p_prob_U[i];
    }
    delete [] p_prob_B;
    delete [] p_prob_U;

    p_prob_B = 0;
    p_prob_U = 0;
}

ostream &operator << (ostream &s, const EST_SCFG_Rule &rule)
{
  (void)rule;
  return s << "<<EST_SCFG_Rule>>";
}

Declare_TList(EST_SCFG_Rule)
#if defined(INSTANTIATE_TEMPLATES)
#include "../base_class/EST_TList.cc"
#include "../base_class/EST_TSortable.cc"

Instantiate_TList(EST_SCFG_Rule)
#endif