public function setWindowStart($start)
    {
        if ($start < 0 || $start > $this->size) {
            throw new PelDataWindowWindowException(
                'Window [%d, %d] does ' . 'not fit in window [0, %d]',
                $start,
                $this->size,
                $this->size
            );
        }
        $this->start += $start;
        $this->size -= $start;
    }