private function compare_float( $a, $b ) {
		$a = number_format( $a, 4 );
		$b = number_format( $b, 4 );
		if ( 0 === $a - $b ) {
			return 0;
		} elseif ( $a - $b < 0 ) {
			return -1;
		} else {
			return 1;
		}
	}