<?php
$dismaxQuery = new SolrDisMaxQuery('lucene');
$boostRecentDocsFunction = "recip(ms(NOW,mydatefield),3.16e-11,1,1)";
$dismaxQuery->setBoostFunction($boostRecentDocsFunction);
echo $dismaxQuery.PHP_EOL;
?>
The above example will output
something similar to:
q=lucene&defType=edismax&bf=recip(ms(NOW,mydatefield),3.16e-11,1,1)