$stat = $article->getPoints($gStatsInterval, $gStatsStart);
            if ($stat !== null) {
                foreach ($stat as $k => $v) {
                    $stat[$k] = $v * $weight;
                }
                $totalStats[] = $stat;
                $totalWeight += $weight;
            }
        }
    }
    /* summarize stats */
    $sumArray = array();
    foreach ($totalStats as $k => $subArray) {
        foreach ($subArray as $id => $value) {
            if (!isset($sumArray[$id])) {
                $sumArray[$id] = 0;
            }
            $sumArray[$id] += $value;
        }
    }
    foreach ($sumArray as $k => $v) {
        $sumArray[$k] = (int) ($sumArray[$k] / $totalWeight);
    }
    $spark = $sumArray;
} else {
    $popularityList = new Toplist\OnsitePopularityList();
    global $gStatsInterval;
    $spark = array_reverse($popularityList->getIndividual($laureate, $gStatsInterval));
}
$api->write_headers();
$api->write_json($spark);