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Elastic Docs ›Elasticsearch.Net and NEST: the .NET clients [6.x] ›Query DSL ›Compound queries

Function Score Query Usage

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IMPORTANT: This documentation is no longer updated. Refer to Elastic's version policy and the latest documentation.

Function Score Query Usage

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Fluent DSL example

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q
.FunctionScore(c => c
    .Name("named_query")
    .Boost(1.1)
    .Query(qq => qq.MatchAll())
    .BoostMode(FunctionBoostMode.Multiply)
    .ScoreMode(FunctionScoreMode.Sum)
    .MaxBoost(20.0)
    .MinScore(1.0)
    .Functions(f => f
        .Exponential(b => b.Field(p => p.NumberOfCommits).Decay(0.5).Origin(1.0).Scale(0.1).Weight(2.1))
        .GaussDate(b => b.Field(p => p.LastActivity).Origin(DateMath.Now).Decay(0.5).Scale("1d"))
        .LinearGeoLocation(b =>
            b.Field(p => p.LocationPoint).Origin(new GeoLocation(70, -70)).Scale(Distance.Miles(1)).MultiValueMode(MultiValueMode.Average))
        .FieldValueFactor(b => b.Field(p => p.NumberOfContributors).Factor(1.1).Missing(0.1).Modifier(FieldValueFactorModifier.Square))
        .RandomScore(r => r.Seed(1337).Field("_seq_no"))
        .RandomScore(r => r.Seed("randomstring").Field("_seq_no"))
        .Weight(1.0)
        .ScriptScore(s => s.Script(ss => ss.Source("Math.log(2 + doc['numberOfCommits'].value)")))
    )
)

Object Initializer syntax example

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new FunctionScoreQuery()
{
    Name = "named_query",
    Boost = 1.1,
    Query = new MatchAllQuery { },
    BoostMode = FunctionBoostMode.Multiply,
    ScoreMode = FunctionScoreMode.Sum,
    MaxBoost = 20.0,
    MinScore = 1.0,
    Functions = new List<IScoreFunction>
    {
        new ExponentialDecayFunction { Origin = 1.0, Decay = 0.5, Field = Field<Project>(p => p.NumberOfCommits), Scale = 0.1, Weight = 2.1 },
        new GaussDateDecayFunction
            { Origin = DateMath.Now, Field = Field<Project>(p => p.LastActivity), Decay = 0.5, Scale = TimeSpan.FromDays(1) },
        new LinearGeoDecayFunction
        {
            Origin = new GeoLocation(70, -70), Field = Field<Project>(p => p.LocationPoint), Scale = Distance.Miles(1),
            MultiValueMode = MultiValueMode.Average
        },
        new FieldValueFactorFunction
        {
            Field = Field<Project>(p => p.NumberOfContributors), Factor = 1.1, Missing = 0.1, Modifier = FieldValueFactorModifier.Square
        },
        new RandomScoreFunction { Seed = 1337, Field = "_seq_no" },
        new RandomScoreFunction { Seed = "randomstring", Field = "_seq_no" },
        new WeightFunction { Weight = 1.0 },
        new ScriptScoreFunction { Script = new ScriptQuery{ Source = "Math.log(2 + doc['numberOfCommits'].value)" } }
    }
}

Example json output.

{
  "function_score": {
    "_name": "named_query",
    "boost": 1.1,
    "boost_mode": "multiply",
    "functions": [
      {
        "exp": {
          "numberOfCommits": {
            "origin": 1.0,
            "scale": 0.1,
            "decay": 0.5
          }
        },
        "weight": 2.1
      },
      {
        "gauss": {
          "lastActivity": {
            "origin": "now",
            "scale": "1d",
            "decay": 0.5
          }
        }
      },
      {
        "linear": {
          "locationPoint": {
            "origin": {
              "lat": 70.0,
              "lon": -70.0
            },
            "scale": "1.0mi"
          },
          "multi_value_mode": "avg"
        }
      },
      {
        "field_value_factor": {
          "field": "numberOfContributors",
          "factor": 1.1,
          "missing": 0.1,
          "modifier": "square"
        }
      },
      {
        "random_score": {
          "seed": 1337,
          "field": "_seq_no"
        }
      },
      {
        "random_score": {
          "seed": "randomstring",
          "field": "_seq_no"
        }
      },
      {
        "weight": 1.0
      },
      {
        "script_score": {
          "script": {
            "source": "Math.log(2 + doc['numberOfCommits'].value)"
          }
        }
      }
    ],
    "max_boost": 20.0,
    "min_score": 1.0,
    "query": {
      "match_all": {}
    },
    "score_mode": "sum"
  }
}
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