As I know, the default one is tf-idf. Also, elasticsearch also provides other scoring choice, like BM25. But if I want to use the default td-idf result and multiplicate one specific field in the index. How can I do it?
Many thanks
perhaps you need to have a mappping https://www.elastic.co/guide/en/elasticsearch/guide/master/changing-similarities.html and https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-function-score-query.html with score mode to multiply. this is just a hunch on what you are trying to do, you need to try it out.
hth
jason