From 985ccc9d1960d10dae22553d3b1b6a6e1e8c85d5 Mon Sep 17 00:00:00 2001
From: Bert Chang <jrweizhang@gmail.com>
Date: Sat, 3 May 2014 01:03:29 +0800
Subject: [PATCH] We don't need to manually handle error anymore.

---
 metrics/pairwise/euclidean.go      |  5 +++--
 metrics/pairwise/euclidean_test.go |  6 +-----
 metrics/pairwise/rbf_kernel.go     | 10 +++-------
 3 files changed, 7 insertions(+), 14 deletions(-)

diff --git a/metrics/pairwise/euclidean.go b/metrics/pairwise/euclidean.go
index f776381..30f8df3 100644
--- a/metrics/pairwise/euclidean.go
+++ b/metrics/pairwise/euclidean.go
@@ -20,9 +20,10 @@ func (self *Euclidean) InnerProduct(vectorX *mat64.Dense, vectorY *mat64.Dense)
 
 // We may need to create Metrics / Vector interface for this
 func (self *Euclidean) Distance(vectorX *mat64.Dense, vectorY *mat64.Dense) float64 {
-	vectorX.Sub(vectorX, vectorY)
+	subVector := mat64.NewDense(0, 0, nil)
+	subVector.Sub(vectorX, vectorY)
 
-	result := self.InnerProduct(vectorX, vectorX)
+	result := self.InnerProduct(subVector, subVector)
 
 	return math.Sqrt(result)
 }
diff --git a/metrics/pairwise/euclidean_test.go b/metrics/pairwise/euclidean_test.go
index 29b8b87..fde2777 100644
--- a/metrics/pairwise/euclidean_test.go
+++ b/metrics/pairwise/euclidean_test.go
@@ -23,11 +23,7 @@ func TestEuclidean(t *testing.T) {
 		})
 
 		Convey("When calculating distance", func() {
-			result, err := euclidean.Distance(vectorX, vectorY)
-
-			Convey("The err should be nil", func() {
-				So(err, ShouldBeNil)
-			})
+			result := euclidean.Distance(vectorX, vectorY)
 
 			Convey("The result should be 3", func() {
 				So(result, ShouldEqual, 3)
diff --git a/metrics/pairwise/rbf_kernel.go b/metrics/pairwise/rbf_kernel.go
index 5d78cca..29c9c17 100644
--- a/metrics/pairwise/rbf_kernel.go
+++ b/metrics/pairwise/rbf_kernel.go
@@ -14,15 +14,11 @@ func NewRBFKernel(gamma float64) *RBFKernel {
 	return &RBFKernel{gamma: gamma}
 }
 
-func (self *RBFKernel) InnerProduct(vectorX *mat64.Dense, vectorY *mat64.Dense) (float64, error) {
+func (self *RBFKernel) InnerProduct(vectorX *mat64.Dense, vectorY *mat64.Dense) float64 {
 	euclidean := NewEuclidean()
-	distance, err := euclidean.Distance(vectorX, vectorY)
-
-	if err != nil {
-		return 0, err
-	}
+	distance := euclidean.Distance(vectorX, vectorY)
 
 	result := math.Exp(self.gamma * math.Pow(distance, 2))
 
-	return result, nil
+	return result
 }