trivial.c

使用具有增量学习的监控式学习方法。包括几个不同的分类算法。

/* Copyright (C) 2002  Mikael Ylikoski
 * See the accompanying file "README" for the full copyright notice */
/**
 * @file
 * Trivial classifier.
 * Classifies according to class frequency or by random.
 *
 * @author  Mikael Ylikoski
 * @date    2002
 */

#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#include "multi.h"
#include "utility.h"
#include "vector.h"


/**
 * Trivial classifier.
 */
typedef struct {
    int seed;		/**< Pseudo random number generator seed */
} trivial_db;


/**
 * Trivial classifier.
 */
typedef struct {
    int df;		/**< Document Frequency for class */
} trivial_class;


/**
 * Create a new classifier database.
 *
 * @return  The new classifier database.
 */
void *
trivial_new_db (const char *opts) {
    trivial_db *db;

    db = my_malloc (sizeof(trivial_db));
    db->seed = 0;

    if (opts) {
	/* seed */
	sscanf (opts, "s=%d", &db->seed);
	if (db->seed != 0)
	    srand (db->seed);
    }

    return db;
}


/**
 * Create a new classifier.
 *
 * @return  The classifier.
 */
void *
trivial_new (void) {
    trivial_class *nbc;

    nbc = my_malloc (sizeof(trivial_class));
    nbc->df = 0;

    return nbc;
}


int
trivial_learn (void *db, void *data, vector *v, int class) {
    trivial_class *trc;

    trc = (trivial_class *)data;

    if (class != 1)
	return -1;
    trc->df++;
    return 0;
}


int
trivial_unlearn (void *db, void *data, vector *v, int class) {
    trivial_class *trc;

    trc = (trivial_class *)data;

    if (class != 1)
	return -1;
    if (trc->df > 0)
	trc->df--;
    return 0;
}


double
trivial_classify (void *db, void *data, vector *v) {
    trivial_class *trc;
    trivial_db *tdb;

    trc = (trivial_class *)data;
    tdb = (trivial_db *)db;

    if (tdb->seed == 0)
	return trc->df;
    else
	return 1 + rand ();
}


/**
 * Keep cygwin happy.
 */
int
main (void) {
    return 0;
}


/**
 * Trivial classifier name.
 */
const char *my_classifier_name = "Trivial";


/**
 * Trivial classifier functions.
 */
const multi_functions my_functions = {
    .new_db = trivial_new_db,
    .new = trivial_new,
    .learn = trivial_learn,
    .unlearn = trivial_unlearn,
    .classify = trivial_classify,
    .option = 0
};