func LoadLibSVMDataset(path string, usingSparseRepresentation bool) data.Dataset {
log.Print("载入libsvm格式文件", path)
content, err := ioutil.ReadFile(path)
if err != nil {
log.Fatalf("无法打开文件\"%v\"，错误提示：%v\n", path, err)
}
lines := strings.Split(string(content), "\n")
minFeature := 10000
maxFeature := 0
labels := make(map[string]int)
labelIndex := 0
for _, l := range lines {
if l == "" {
continue
}
fields := strings.Split(l, " ")
_, ok := labels[fields[0]]
if !ok {
labels[fields[0]] = labelIndex
labelIndex++
}
for i := 1; i < len(fields); i++ {
if fields[i] == "" {
continue
}
fs := strings.Split(fields[i], ":")
fid, _ := strconv.Atoi(fs[0])
if fid > maxFeature {
maxFeature = fid
}
if fid < minFeature {
minFeature = fid
}
}
}
if minFeature == 0 || maxFeature < 2 {
log.Fatal("文件输入格式不合法")
}
log.Printf("feature 数目 %d", maxFeature)
log.Printf("label 数目 %d", len(labels))
set := data.NewInmemDataset()
for _, l := range lines {
if l == "" {
continue
}
fields := strings.Split(l, " ")
instance := new(data.Instance)
instance.Output = &data.InstanceOutput{
Label: labels[fields[0]],
LabelString: fields[0],
}
if usingSparseRepresentation {
instance.NamedFeatures = make(map[string]float64)
} else {
instance.Features = util.NewVector(maxFeature + 1)
}
// 常数项
if !usingSparseRepresentation {
instance.Features.Set(0, 1)
}
for i := 1; i < len(fields); i++ {
if fields[i] == "" {
continue
}
fs := strings.Split(fields[i], ":")
fid, _ := strconv.Atoi(fs[0])
value, _ := strconv.ParseFloat(fs[1], 64)
if usingSparseRepresentation {
instance.NamedFeatures[fs[0]] = value
} else {
instance.Features.Set(fid, value)
}
}
set.AddInstance(instance)
}
set.Finalize()
log.Print("载入数据样本数目 ", set.NumInstances())
return set
}
func TestTrainWithNamedFeatures(t *testing.T) {
set := data.NewInmemDataset()
instance1 := new(data.Instance)
instance1.NamedFeatures = map[string]float64{
"1": 1,
"2": 1,
"3": 1,
"4": 3,
}
instance1.Output = &data.InstanceOutput{Label: 0}
set.AddInstance(instance1)
instance2 := new(data.Instance)
instance2.NamedFeatures = map[string]float64{
"1": 1,
"2": 3,
"3": 1,
"4": 5,
}
instance2.Output = &data.InstanceOutput{Label: 0}
set.AddInstance(instance2)
instance3 := new(data.Instance)
instance3.NamedFeatures = map[string]float64{
"1": 1,
"2": 3,
"3": 4,
"4": 7,
}
instance3.Output = &data.InstanceOutput{Label: 1}
set.AddInstance(instance3)
instance4 := new(data.Instance)
instance4.NamedFeatures = map[string]float64{
"1": 1,
"2": 2,
"3": 8,
"4": 6,
}
instance4.Output = &data.InstanceOutput{Label: 1}
set.AddInstance(instance4)
set.Finalize()
gdTrainerOptions := TrainerOptions{
Optimizer: optimizer.OptimizerOptions{
OptimizerName: "gd",
RegularizationScheme: 2,
RegularizationFactor: 1,
LearningRate: 0.1,
ConvergingDeltaWeight: 1e-6,
ConvergingSteps: 3,
MaxIterations: 0,
GDBatchSize: 0, // full-bath
},
}
gdTrainer := NewMaxEntClassifierTrainer(gdTrainerOptions)
lbfgsTrainerOptions := TrainerOptions{
Optimizer: optimizer.OptimizerOptions{
OptimizerName: "lbfgs",
RegularizationScheme: 2,
RegularizationFactor: 1,
LearningRate: 1,
ConvergingDeltaWeight: 1e-6,
ConvergingSteps: 3,
MaxIterations: 0,
},
}
lbfgsTrainer := NewMaxEntClassifierTrainer(lbfgsTrainerOptions)
lbfgsTrainer.Train(set)
gdTrainer.Train(set).Write("test.mlf")
model := LoadModel("test.mlf")
util.Expect(t, "0", model.Predict(instance1).Label)
util.Expect(t, "0", model.Predict(instance2).Label)
util.Expect(t, "1", model.Predict(instance3).Label)
util.Expect(t, "1", model.Predict(instance4).Label)
}