1
restaurant-search/util.go

92 lines
2.9 KiB
Go

/*
* Copyright (c) 2015 Alex Yatskov <alex@foosoft.net>
* Author: Alex Yatskov <alex@foosoft.net>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
package main
import "sort"
func innerProduct(features1 Features, features2 Features) float32 {
var result float32
for key, value1 := range features1 {
value2, _ := features2[key]
result += value1 * value2
}
return result
}
func walkMatches(records Records, features Features, minScore float32, callback func(Record, float32)) {
for _, record := range records {
if score := innerProduct(features, record.features); score >= minScore {
callback(record, score)
}
}
}
func statRecords(records Records, features Features, minScore float32) RecordStats {
var stats RecordStats
walkMatches(records, features, minScore, func(record Record, score float32) {
stats.compatibility += record.compatibility
stats.count++
})
return stats
}
func stepRange(rng Range, steps int, callback func(float32)) {
stepSize := (rng.max - rng.min) / float32(steps)
for i := 0; i < steps; i++ {
stepMax := rng.max - stepSize*float32(i)
stepMin := stepMax - stepSize
stepMid := (stepMin + stepMax) / 2
callback(stepMid)
}
}
func findRecords(records Records, features Features, minScore float32) {
var foundRecords Records
walkMatches(records, features, minScore, func(record Record, score float32) {
foundRecords = append(foundRecords, record)
})
sort.Sort(foundRecords)
}
func project(records Records, features Features, featureName string, minScore float32, rng Range, steps int) []Projection {
sampleFeatures := make(Features)
for key, value := range features {
sampleFeatures[key] = value
}
var projection []Projection
stepRange(rng, steps, func(sample float32) {
sampleFeatures[featureName] = sample
stats := statRecords(records, sampleFeatures, minScore)
projection = append(projection, Projection{sample: sample, stats: stats})
})
return projection
}