Rank features datatypeedit

A rank_features field can index numeric feature vectors, so that they can later be used to boost documents in queries with a rank_feature query.

It is analogous to the rank_feature datatype but is better suited when the list of features is sparse so that it wouldn’t be reasonable to add one field to the mappings for each of them.

PUT my_index
{
  "mappings": {
    "properties": {
      "topics": {
        "type": "rank_features" 
      }
    }
  }
}

PUT my_index/_doc/1
{
  "topics": { 
    "politics": 20,
    "economics": 50.8
  }
}

PUT my_index/_doc/2
{
  "topics": {
    "politics": 5.2,
    "sports": 80.1
  }
}

GET my_index/_search
{
  "query": {
    "rank_feature": {
      "field": "topics.politics"
    }
  }
}

Rank features fields must use the rank_features field type

Rank features fields must be a hash with string keys and strictly positive numeric values

Note

rank_features fields only support single-valued features and strictly positive values. Multi-valued fields and zero or negative values will be rejected.

Note

rank_features fields do not support sorting or aggregating and may only be queried using rank_feature queries.

Note

rank_features fields only preserve 9 significant bits for the precision, which translates to a relative error of about 0.4%.