Форум по Forex Tester 5

Код: Выделить всё

function trend($currency, $offset, $time) {
	$query = "SELECT `close`, `date` FROM `history_forex_h` WHERE `currency` = '$currency' AND `date` < '$time' AND `date` > DATE_SUB('$time', INTERVAL $offset DAY) ORDER BY `date`";
	$set = select($query);
	$sum_w = 0;
	$sum_t = 0;
	$t = 0;
	$sum_t2 = 0;
	$sum_tw = 0;
	while ($row = mysql_fetch_array($set)) {
		$t++;
		$sum_t = $sum_t + $t;
		$sum_t2 = $sum_t2 + $t*$t;
		$sum_w = $sum_w + $row[close];
		$sum_tw = $sum_tw + $row[close]*$t;
	}
	$b = ($sum_tw - $sum_t2*$sum_w/$sum_t)/($sum_t - $t*$sum_t2/$sum_t);
	$a = ($sum_w - $t*$b)/$sum_t;
	$sum_w_x = 0;
	$n=0;
	$query = "SELECT `close`, `date` FROM `history_forex_h` WHERE `currency` = '$currency' AND `date` < '$time' AND `date` > DATE_SUB('$time', INTERVAL $offset DAY) ORDER BY `date`";
	$set = select($query);
	while ($row = mysql_fetch_array($set)) {
		$n++;
		$w = $a*$n + $b;
		$y = $row[close] - $w;
		$sum_w_x = $sum_w_x + pow($y, 2);
	}
	$s = sqrt($sum_w_x/($n-1));
	$return[0] = $w;
	$return[1] = $s;
	$return[2] = $a;
	$return[3] = $b;
	return $return;
}