pairwise summation
... that pairwise summation of a sequence (breaking it in half and summing each half separately first) greatly reduces rounding errors?
... that <b id="mwCa4"><a href="./Pairwise_summation" id="mwCa8" rel="mw:WikiLink" title="Pairwise summation">pairwise summation</a></b> of a sequence (breaking it in half and summing each half separately first) greatly reduces rounding errors?