1
restaurant-search/util.go

139 lines
3.9 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
type Features map[string]float32
type Record struct {
features Features
compatibility float32
}
type RecordStats struct {
compatibility float32
count int
}
type Range struct {
min float32
max float32
}
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 []Record, 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 []Record, 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 step(rng Range, steps int, minScore float32, 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)
}
}
// function findRecords(data, features, minScore) {
// var results = [];
// walkMatches(data, features, minScore, function(record, score) {
// results.push({
// name: record.name,
// score: score,
// distanceToUser: record.distanceToUser / 1000.0,
// distanceToStn: record.distanceToStn / 1000.0,
// closestStn: record.closestStn,
// accessCount: record.accessCount,
// id: record.id
// });
// });
// results.sort(function(a, b) {
// return b.score - a.score;
// });
// return results;
// }
// function project(data, features, feature, minScore, range, steps) {
// var sample = _.clone(features);
// var results = [];
// step(range, steps, function(position) {
// sample[feature] = position;
// results.push({
// sample: position,
// stats: statRecords(data, sample, minScore)
// });
// });
// return results;
// }
// function buildHints(data, features, feature, minScore, range, steps) {
// var projection = project(
// data,
// features,
// feature,
// minScore,
// range,
// steps
// );
// var hints = [];
// _.each(projection, function(result) {
// hints.push({
// sample: result.sample,
// stats: result.stats
// });
// });
// return hints;
// }