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Rank feature field type

A rank_feature field can index numbers so that they can later be used to boost documents in queries with a rank_feature query.

resp = client.indices.create(
    index="my-index-000001",
    mappings={
        "properties": {
            "pagerank": {
                "type": "rank_feature"
            },
            "url_length": {
                "type": "rank_feature",
                "positive_score_impact": False
            }
        }
    },
)
print(resp)

resp1 = client.index(
    index="my-index-000001",
    id="1",
    document={
        "pagerank": 8,
        "url_length": 22
    },
)
print(resp1)

resp2 = client.search(
    index="my-index-000001",
    query={
        "rank_feature": {
            "field": "pagerank"
        }
    },
)
print(resp2)

response = client.indices.create(
  index: 'my-index-000001',
  body: {
    mappings: {
      properties: {
        pagerank: {
          type: 'rank_feature'
        },
        url_length: {
          type: 'rank_feature',
          positive_score_impact: false
        }
      }
    }
  }
)
puts response

response = client.index(
  index: 'my-index-000001',
  id: 1,
  body: {
    pagerank: 8,
    url_length: 22
  }
)
puts response

response = client.search(
  index: 'my-index-000001',
  body: {
    query: {
      rank_feature: {
        field: 'pagerank'
      }
    }
  }
)
puts response

const response = await client.indices.create({
  index: "my-index-000001",
  mappings: {
    properties: {
      pagerank: {
        type: "rank_feature",
      },
      url_length: {
        type: "rank_feature",
        positive_score_impact: false,
      },
    },
  },
});
console.log(response);

const response1 = await client.index({
  index: "my-index-000001",
  id: 1,
  document: {
    pagerank: 8,
    url_length: 22,
  },
});
console.log(response1);

const response2 = await client.search({
  index: "my-index-000001",
  query: {
    rank_feature: {
      field: "pagerank",
    },
  },
});
console.log(response2);

PUT my-index-000001
{
  "mappings": {
    "properties": {
      "pagerank": {
        "type": "rank_feature" 
      },
      "url_length": {
        "type": "rank_feature",
        "positive_score_impact": false 
      }
    }
  }
}

PUT my-index-000001/_doc/1
{
  "pagerank": 8,
  "url_length": 22
}

GET my-index-000001/_search
{
  "query": {
    "rank_feature": {
      "field": "pagerank"
    }
  }
}

	Rank feature fields must use the `rank_feature` field type
	Rank features that correlate negatively with the score need to declare it

rank_feature fields only support single-valued fields and strictly positive values. Multi-valued fields and negative values will be rejected.

rank_feature fields do not support querying, sorting or aggregating. They may only be used within rank_feature queries.

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

Rank features that correlate negatively with the score should set positive_score_impact to false (defaults to true). This will be used by the rank_feature query to modify the scoring formula in such a way that the score decreases with the value of the feature instead of increasing. For instance in web search, the url length is a commonly used feature which correlates negatively with scores.

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https://www.elastic.co/guide/en/elasticsearch/reference/8.17/rank-feature.html