Fukuball\Jieba\Finalseg::viterbi PHP Method

    public static function viterbi($sentence, $options = array())
    {
        $defaults = array('mode' => 'default');
        $options = array_merge($defaults, $options);
        $obs = $sentence;
        $states = array('B', 'M', 'E', 'S');
        $V = array();
        $V[0] = array();
        $path = array();
        foreach ($states as $key => $state) {
            $y = $state;
            $c = mb_substr($obs, 0, 1, 'UTF-8');
            $prob_emit = 0.0;
            if (isset(self::$prob_emit[$y][$c])) {
                $prob_emit = self::$prob_emit[$y][$c];
            } else {
                $prob_emit = MIN_FLOAT;
            }
            $V[0][$y] = self::$prob_start[$y] + $prob_emit;
            $path[$y] = $y;
        }
        for ($t = 1; $t < mb_strlen($obs, 'UTF-8'); $t++) {
            $c = mb_substr($obs, $t, 1, 'UTF-8');
            $V[$t] = array();
            $newpath = array();
            foreach ($states as $key => $state) {
                $y = $state;
                $temp_prob_array = array();
                foreach ($states as $key => $state0) {
                    $y0 = $state0;
                    $prob_trans = 0.0;
                    if (isset(self::$prob_trans[$y0][$y])) {
                        $prob_trans = self::$prob_trans[$y0][$y];
                    } else {
                        $prob_trans = MIN_FLOAT;
                    }
                    $prob_emit = 0.0;
                    if (isset(self::$prob_emit[$y][$c])) {
                        $prob_emit = self::$prob_emit[$y][$c];
                    } else {
                        $prob_emit = MIN_FLOAT;
                    }
                    $temp_prob_array[$y0] = $V[$t - 1][$y0] + $prob_trans + $prob_emit;
                }
                arsort($temp_prob_array);
                $max_prob = reset($temp_prob_array);
                $max_key = key($temp_prob_array);
                $V[$t][$y] = $max_prob;
                if (is_array($path[$max_key])) {
                    $newpath[$y] = array();
                    foreach ($path[$max_key] as $key => $path_value) {
                        array_push($newpath[$y], $path_value);
                    }
                    array_push($newpath[$y], $y);
                } else {
                    $newpath[$y] = array($path[$max_key], $y);
                }
            }
            $path = $newpath;
        }
        $es_states = array('E', 'S');
        $temp_prob_array = array();
        $len = mb_strlen($obs, 'UTF-8');
        foreach ($es_states as $key => $state) {
            $y = $state;
            $temp_prob_array[$y] = $V[$len - 1][$y];
        }
        arsort($temp_prob_array);
        $prob = reset($temp_prob_array);
        $state = key($temp_prob_array);
        return array("prob" => $prob, "pos_list" => $path[$state]);
    }