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Save and load a classifier #1

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70 changes: 56 additions & 14 deletions naive/naive.go
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Original file line number Diff line number Diff line change
Expand Up @@ -2,8 +2,11 @@ package naive

import (
"bytes"
"encoding/gob"
"errors"
"io"
"io/ioutil"
"os"
"sync"

"github.com/n3integration/classifier"
Expand All @@ -17,17 +20,17 @@ type Option func(c *Classifier) error

// Classifier implements a naive bayes classifier
type Classifier struct {
feat2cat map[string]map[string]int
catCount map[string]int
Feat2Cat map[string]map[string]int
CatCount map[string]int
tokenizer classifier.Tokenizer
mu sync.RWMutex
}

// New initializes a new naive Classifier using the standard tokenizer
func New(opts ...Option) *Classifier {
c := &Classifier{
feat2cat: make(map[string]map[string]int),
catCount: make(map[string]int),
Feat2Cat: make(map[string]map[string]int),
CatCount: make(map[string]int),
tokenizer: classifier.NewTokenizer(),
}
for _, opt := range opts {
Expand All @@ -36,6 +39,25 @@ func New(opts ...Option) *Classifier {
return c
}

// Load reads a classifier from a binary file
func Load(path string) (*Classifier, error) {
c := &Classifier{
tokenizer: classifier.NewTokenizer(),
}

file, err := ioutil.ReadFile(path)
if err != nil {
return nil, err
}

dec := gob.NewDecoder(bytes.NewBuffer(file))
if err = dec.Decode(c); err != nil {
return nil, err
}

return c, err
}

// Tokenizer overrides the classifier's default Tokenizer
func Tokenizer(t classifier.Tokenizer) Option {
return func(c *Classifier) error {
Expand Down Expand Up @@ -92,42 +114,62 @@ func (c *Classifier) ClassifyString(doc string) (string, error) {
return c.Classify(asReader(doc))
}

// Save writes a classifier to a binary file
func (c *Classifier) Save(path string) (err error) {
var network bytes.Buffer

file, err := os.Create(path)
if err != nil {
return err
}
defer file.Close()

enc := gob.NewEncoder(&network)
err = enc.Encode(c)
if err != nil {
return err
}

_, err = file.Write(network.Bytes())
return err
}

func (c *Classifier) addFeature(feature string, category string) {
if _, ok := c.feat2cat[feature]; !ok {
c.feat2cat[feature] = make(map[string]int)
if _, ok := c.Feat2Cat[feature]; !ok {
c.Feat2Cat[feature] = make(map[string]int)
}
c.feat2cat[feature][category]++
c.Feat2Cat[feature][category]++
}

func (c *Classifier) featureCount(feature string, category string) float64 {
if _, ok := c.feat2cat[feature]; ok {
return float64(c.feat2cat[feature][category])
if _, ok := c.Feat2Cat[feature]; ok {
return float64(c.Feat2Cat[feature][category])
}
return 0.0
}

func (c *Classifier) addCategory(category string) {
c.catCount[category]++
c.CatCount[category]++
}

func (c *Classifier) categoryCount(category string) float64 {
if _, ok := c.catCount[category]; ok {
return float64(c.catCount[category])
if _, ok := c.CatCount[category]; ok {
return float64(c.CatCount[category])
}
return 0.0
}

func (c *Classifier) count() int {
sum := 0
for _, value := range c.catCount {
for _, value := range c.CatCount {
sum += value
}
return sum
}

func (c *Classifier) categories() []string {
var keys []string
for k := range c.catCount {
for k := range c.CatCount {
keys = append(keys, k)
}
return keys
Expand Down