protected function loadMapRow()
    {
        $ret = [
            "cnt" => 0,
            "rec" => [],
            "dat" => []
            ];
        if (sizeof($this->datMap) > 0) {
            foreach ($this->datMap as $let => $d) {
                $ret["dat"][$let] = [
                    "sum" => 0,
                    "avg" => 0,
                    "ids" => []
                    ];
            }
        }
        return $ret;
    }