In file ../include/EST_SCFG.h:

class EST_SCFG_traintest

A class used to train (and test) SCFGs is an extention of EST_SCFG.

Inheritance:

Public Methods

void	test_corpus () Test the current grammar against the current corpus print summary.
void	test_crossbrackets () Test the current grammar against the current corpus.
void	load_corpus (const EST_String &filename) Load a corpus from the given file.
void	train_inout (int passes, int startpass, int checkpoint, int spread, const EST_String &outfile) Train a grammar using the loaded corpus.

Inherited from EST_SCFG:

Public Methods

Constructor and initialisation functions

EST_SCFG(LISP rules)

Initialize from a set of rules

utility functions

void set_rules(LISP rules)

Set (or reset) rules from external source after construction

LISP get_rules()

Return rules as LISP list

SCFGRuleList rules

The rules themselves

void find_terms_nonterms(EST_StrList &nt, EST_StrList &t, LISP rules)

Find the terminals and nonterminals in the given grammar, adding them to the appropriate given string lists

EST_String nonterminal(int p) const

Convert nonterminal index to string form

EST_String terminal(int m) const

Convert terminal index to string form

int nonterminal(const EST_String &p) const

Convert nonterminal string to index

int terminal(const EST_String &m) const

Convert terminal string to index

int num_nonterminals() const

Number of nonterminals

int num_terminals() const

Number of terminals

double prob_B(int p, int q, int r) const

The rule probability of given binary rule

double prob_U(int p, int m) const

The rule probability of given unary rule

void set_rule_prob_cache()

(re-)set rule probability caches

file i/o functions

EST_read_status load(const EST_String &filename)

Load grammar from named file

EST_write_status save(const EST_String &filename)

Save current grammar to named file

Documentation

A class used to train (and test) SCFGs is an extention of EST_SCFG.

This offers an implementation of Pereira and Schabes ``Inside-Outside reestimation from partially bracket corpora.'' ACL 1992.

A SCFG maybe trained from a corpus (optionally) containing brackets over a series of passes reestimating the grammar probabilities after each pass. This basically extends the EST_SCFG class adding support for a bracket corpus and various indexes for efficient use of the grammar.

void test_corpus()

Test the current grammar against the current corpus print summary.

Cross entropy measure only is given.

void test_crossbrackets()

Test the current grammar against the current corpus.

Sumamry includes percentage of cross bracketing accuracy and percentage of fully correct parses.

void load_corpus(const EST_String &filename)

Load a corpus from the given file.

Each setence in the corpus should be contained in parentheses. Additional paranethesis may be used to denote phrasing within a sentence. The corpus is read using the LISP reader so LISP conventions shold apply, notable single quotes should appear within double quotes.

void train_inout(int passes, int startpass, int checkpoint, int spread, const EST_String &outfile)

Train a grammar using the loaded corpus.

Parameters:

passes - the number of training passes desired.
startpass - from which pass to start from
checkpoint - save the grammar every n passes
spread - Percentage of corpus to use on each pass, this cycles through the corpus on each pass.

This class has no child classes.

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This page is part of the Edinburgh Speech Tools Library documentation
Copyright University of Edinburgh 1997
Contact: speech_tools@cstr.ed.ac.uk