small tweaks, add docs

posseg/posseg.go

@@ -20,6 +20,8 @@ type WordTag struct {
 	Word, Tag string
 }
 
+// Set dictionary, it could be absolute path of dictionary file, or dictionary
+// name in current diectory.
 func SetDictionary(dictFileName string) error {
 	err := jiebago.SetDictionary(dictFileName)
 	if err != nil {
@@ -42,7 +44,7 @@ func cutDetailInternal(sentence string) chan WordTag {
 
 	go func() {
 		runes := []rune(sentence)
-		_, posList := Viterbi(runes)
+		_, posList := viterbi(runes)
 		begin := 0
 		next := 0
 		for i, char := range runes {
@@ -232,6 +234,8 @@ func cutDAGNoHMM(sentence string) chan WordTag {
 	return result
 }
 
+// Tags the POS of each word after segmentation, using labels compatible with
+// ictclas.
 func Cut(sentence string, HMM bool) chan WordTag {
 	for key := range jiebago.UserWordTagTab {
 		wordTagMap[key] = jiebago.UserWordTagTab[key]

posseg/prob_emit.go

@@ -1,12 +1,14 @@
 package posseg
 
+const MinFloat = -3.14e100
+
 type RuneFloatMap map[rune]float64
 
 func (m RuneFloatMap) Get(key rune) float64 {
 	if _, ok := m[key]; ok {
 		return m[key]
 	} else {
-		return MIN_FLOAT
+		return MinFloat
 	}
 }
 

posseg/viterbi.go

@@ -5,8 +5,6 @@ import (
 	"sort"
 )
 
-const MIN_FLOAT = -3.14e100
-
 type StateTag struct {
 	State byte
 	Tag   string
@@ -49,7 +47,7 @@ func (pss ProbStates) Swap(i, j int) {
 	pss[i], pss[j] = pss[j], pss[i]
 }
 
-func Viterbi(obs []rune) (float64, []StateTag) {
+func viterbi(obs []rune) (float64, []StateTag) {
 	obsLength := len(obs)
 	V := make([]map[StateTag]float64, obsLength)
 	V[0] = make(map[StateTag]float64)

posseg/viterbi_test.go

@@ -30,8 +30,8 @@ var (
 
 func TestViterbi(t *testing.T) {
 	ss := "李小福是创新办主任也是云计算方面的专家;"
-	prob, route := Viterbi([]rune(ss))
-	if prob != MIN_FLOAT {
+	prob, route := viterbi([]rune(ss))
+	if prob != MinFloat {
 		t.Error(prob)
 	}
 	if len(route) != len(route1) {