Merge pull request #26 from mathetake/fix/zero-vector-error

fix zero-vector handling

index/index_test.go

@@ -1,9 +1,10 @@
 package index
 
 import (
+	"testing"
+
 	"github.com/bmizerany/assert"
 	"github.com/mathetake/gann/item"
-	"testing"
 )
 
 func TestInitializeWithNormalize(t *testing.T) {

item/arithmetic.go

@@ -5,6 +5,7 @@ import (
 	"math"
 	"math/rand"
 	"time"
+	"github.com/pkg/errors"
 )
 
 const (
@@ -14,14 +15,15 @@ const (
 	centroidCalcRatio = float32(0.0001)
 )
 
-func Normalize(v1 Vector) {
-	n := norm(v1)
+func Normalize(v Vector) error {
+	n := norm(v)
 	if n == 0 {
-		panic("zero vector given.")
+		return errors.Errorf("zero vector is given.")
 	}
-	for i := 0; i < len(v1); i++ {
-		v1[i] = v1[i] / n
+	for i := 0; i < len(v); i++ {
+		v[i] = v[i] / n
 	}
+	return nil
 }
 
 func DotProduct(v1, v2 Vector) (ret float32) {
@@ -102,23 +104,17 @@ func GetNormalVectorOfSplittingHyperPlane(vs []Vector, dim int) Vector {
 		}
 	}
 
-	isZero := true
 	for d := 0; d < dim; d++ {
 		v := c0[d] - c1[d]
 		ret[d] += v
-		if v != 0 {
-			isZero = false
-		}
 	}
 
-	if isZero {
+	// normalize
+	err := Normalize(ret)
+	if err != nil {
 		d := rand.Intn(dim)
 		ret[d] = 1
-		return ret
 	}
-
-	// normalize
-	Normalize(ret)
 	return ret
 }
 

item/arithmetic_test.go

@@ -1,15 +1,17 @@
 package item
 
 import (
-	"github.com/bmizerany/assert"
 	"math/rand"
 	"testing"
 	"time"
+
+	"github.com/bmizerany/assert"
 )
 
 func TestNormalize(t *testing.T) {
 	v1 := []float32{2, 0}
-	Normalize(v1)
+	err := Normalize(v1)
+	assert.Equal(t, nil, err)
 	assert.Equal(t, []float32{1, 0}, v1)
 }
 

node/node_test.go

@@ -7,8 +7,8 @@ import (
 
 	"sync"
 
+	"github.com/bmizerany/assert"
 	"github.com/mathetake/gann/item"
-	"github.com/stretchr/testify/assert"
 )
 
 func TestIsLeaf(t *testing.T) {

node/quque_test.go

@@ -6,7 +6,7 @@ import (
 
 	"math"
 
-	"gopkg.in/go-playground/assert.v1"
+	"github.com/bmizerany/assert"
 )
 
 func TestPriorityQueue(t *testing.T) {