假设tf归一化设置为unscaled-log，logtf如何工作，任何人都可以根据公式给出准确的示例
<qry:term weight="64">
<qry:score formula="8*weight*logtf" computation="512*11">5632</qry:score>
<qry:key>4597112759904035308</qry:key>
<qry:annotation>element(title,word("obama"))</qry:annotation>
</qry:term>