forked from blevesearch/bleve
/
scorer_constant.go
108 lines (92 loc) · 2.74 KB
/
scorer_constant.go
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// Copyright (c) 2014 Couchbase, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package scorer
import (
"fmt"
"github.com/blevesearch/bleve/index"
"github.com/blevesearch/bleve/search"
)
type ConstantScorer struct {
constant float64
boost float64
options search.SearcherOptions
queryNorm float64
queryWeight float64
queryWeightExplanation *search.Explanation
}
func NewConstantScorer(constant float64, boost float64, options search.SearcherOptions) *ConstantScorer {
rv := ConstantScorer{
options: options,
queryWeight: 1.0,
constant: constant,
boost: boost,
}
return &rv
}
func (s *ConstantScorer) Weight() float64 {
sum := s.boost
return sum * sum
}
func (s *ConstantScorer) SetQueryNorm(qnorm float64) {
s.queryNorm = qnorm
// update the query weight
s.queryWeight = s.boost * s.queryNorm
if s.options.Explain {
childrenExplanations := make([]*search.Explanation, 2)
childrenExplanations[0] = &search.Explanation{
Value: s.boost,
Message: "boost",
}
childrenExplanations[1] = &search.Explanation{
Value: s.queryNorm,
Message: "queryNorm",
}
s.queryWeightExplanation = &search.Explanation{
Value: s.queryWeight,
Message: fmt.Sprintf("ConstantScore()^%f, product of:", s.boost),
Children: childrenExplanations,
}
}
}
func (s *ConstantScorer) Score(ctx *search.SearchContext, id index.IndexInternalID) *search.DocumentMatch {
var scoreExplanation *search.Explanation
score := s.constant
if s.options.Explain {
scoreExplanation = &search.Explanation{
Value: score,
Message: fmt.Sprintf("ConstantScore()"),
}
}
// if the query weight isn't 1, multiply
if s.queryWeight != 1.0 {
score = score * s.queryWeight
if s.options.Explain {
childExplanations := make([]*search.Explanation, 2)
childExplanations[0] = s.queryWeightExplanation
childExplanations[1] = scoreExplanation
scoreExplanation = &search.Explanation{
Value: score,
Message: fmt.Sprintf("weight(^%f), product of:", s.boost),
Children: childExplanations,
}
}
}
rv := ctx.DocumentMatchPool.Get()
rv.IndexInternalID = id
rv.Score = score
if s.options.Explain {
rv.Expl = scoreExplanation
}
return rv
}