anchor.diff:      }],
       "metric": {
           "mean_reciprocal_rank": {
  +            "k" : 20,
               "relevant_rating_threshold" : 1
           }
       }
  
positive.code: [cols="<,<",options="header",]
  |=======================================================================
  |Parameter |Description
  |`relevant_rating_threshold` |Sets the rating threshold above which documents are considered to be
  "relevant". Defaults to `1`.
  |`ignore_unlabeled` |controls how unlabeled documents in the search results are counted.
  If set to 'true', unlabeled documents are ignored and neither count as relevant or irrelevant. Set to 'false' (the default), they are treated as irrelevant.
  
negative.code: returns typical information retrieval metrics like _mean reciprocal rank_,
  _precision_ or _discounted cumulative gain_.
  
  [float]
  === Overview
  
  