title: Custom scoring in ElasticSearch
body: <p>How do i use the following function? (For elastica in PHP with respect to Function Score query)</p>
  
  <p>addScriptScoreFunction($script, $filter)</p>
  
  <p>Does the filter filter out results or only score based on the script for those that pass the filter? How efficient is the scoring? </p>
  
  <p>Also can i add more than one script score function to function score query?</p>