/
search.go
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/
search.go
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// Copyright © 2020 wego authors
//
// 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 search
import (
"fmt"
"os"
"sort"
"github.com/olekukonko/tablewriter"
"github.com/pkg/errors"
"github.com/wujunfeng1/wego/pkg/embedding"
"github.com/wujunfeng1/wego/pkg/embedding/embutil"
"github.com/wujunfeng1/wego/pkg/search/searchutil"
)
// Neighbor stores the word with cosine similarity value on the target.
type Neighbor struct {
Word string
Rank uint
Similarity float64
}
type Neighbors []Neighbor
func (neighbors Neighbors) Describe() {
table := make([][]string, len(neighbors))
for i, n := range neighbors {
table[i] = []string{
fmt.Sprintf("%d", n.Rank),
n.Word,
fmt.Sprintf("%f", n.Similarity),
}
}
writer := tablewriter.NewWriter(os.Stdout)
writer.SetHeader([]string{"Rank", "Word", "Similarity"})
writer.SetBorder(false)
writer.AppendBulk(table)
writer.Render()
}
type Searcher struct {
Items embedding.Embeddings
}
func New(embs ...embedding.Embedding) (*Searcher, error) {
if err := embedding.Embeddings(embs).Validate(); err != nil {
return nil, err
}
return &Searcher{
Items: embs,
}, nil
}
func (s *Searcher) SearchInternal(word string, k int) (Neighbors, error) {
var q embedding.Embedding
for _, item := range s.Items {
if item.Word == word {
q = item
break
}
}
if q.Word == "" {
return nil, errors.Errorf("%s is not found in searcher", word)
}
neighbors, err := s.Search(q, k, word)
if err != nil {
return nil, err
}
return neighbors, nil
}
func (s *Searcher) SearchVector(query []float64, k int) (Neighbors, error) {
return s.Search(embedding.Embedding{
Vector: query,
Norm: embutil.Norm(query),
}, k)
}
func (s *Searcher) Search(query embedding.Embedding, k int, ignoreWord ...string) (Neighbors, error) {
neighbors := make(Neighbors, len(s.Items))
for i, item := range s.Items {
var ignore bool
for _, w := range ignoreWord {
ignore = ignore || item.Word == w
}
if !ignore {
neighbors[i] = Neighbor{
Word: item.Word,
Similarity: searchutil.Cosine(query.Vector, item.Vector, query.Norm, item.Norm),
}
}
}
sort.SliceStable(neighbors, func(i, j int) bool {
return neighbors[i].Similarity > neighbors[j].Similarity
})
for i := range neighbors {
neighbors[i].Rank = uint(i) + 1
}
if k > len(s.Items) {
k = len(s.Items)
}
return neighbors[:k], nil
}