From 9a6133255120b6afa2c843e65101c7a914f64178 Mon Sep 17 00:00:00 2001
From: Bert Chang <jrweizhang@gmail.com>
Date: Sat, 3 May 2014 22:47:41 +0800
Subject: [PATCH] Make manhattan support both col&row vectors.

---
 metrics/pairwise/euclidean_test.go   |  5 +++--
 metrics/pairwise/manhattan.go        | 15 +++++++++++++--
 metrics/pairwise/manhattan_test.go   | 21 ++++++++++++++++++---
 metrics/pairwise/poly_kernel_test.go |  5 +++--
 metrics/pairwise/rbf_kernel_test.go  |  5 +++--
 5 files changed, 40 insertions(+), 11 deletions(-)

diff --git a/metrics/pairwise/euclidean_test.go b/metrics/pairwise/euclidean_test.go
index fde2777..d022ae6 100644
--- a/metrics/pairwise/euclidean_test.go
+++ b/metrics/pairwise/euclidean_test.go
@@ -8,11 +8,12 @@ import (
 )
 
 func TestEuclidean(t *testing.T) {
+	var vectorX, vectorY *mat64.Dense
 	euclidean := NewEuclidean()
 
 	Convey("Given two vectors", t, func() {
-		vectorX := mat64.NewDense(3, 1, []float64{1, 2, 3})
-		vectorY := mat64.NewDense(3, 1, []float64{2, 4, 5})
+		vectorX = mat64.NewDense(3, 1, []float64{1, 2, 3})
+		vectorY = mat64.NewDense(3, 1, []float64{2, 4, 5})
 
 		Convey("When doing inner product", func() {
 			result := euclidean.InnerProduct(vectorX, vectorY)
diff --git a/metrics/pairwise/manhattan.go b/metrics/pairwise/manhattan.go
index 847f05c..c734f31 100644
--- a/metrics/pairwise/manhattan.go
+++ b/metrics/pairwise/manhattan.go
@@ -13,13 +13,24 @@ func NewManhattan() *Manhattan {
 }
 
 func (self *Manhattan) Distance(vectorX *mat64.Dense, vectorY *mat64.Dense) float64 {
+	var length int
 	subVector := mat64.NewDense(0, 0, nil)
 	subVector.Sub(vectorX, vectorY)
 
-	r, _ := subVector.Dims()
+	r, c := subVector.Dims()
+
+	if r == 1 {
+		// Force transpose to column vector
+		subVector.TCopy(subVector)
+		length = c
+	} else if c == 1 {
+		length = r
+	} else {
+		panic(mat64.ErrShape)
+	}
 
 	result := .0
-	for i := 0; i < r; i++ {
+	for i := 0; i < length; i++ {
 		result += math.Abs(subVector.At(i, 0))
 	}
 
diff --git a/metrics/pairwise/manhattan_test.go b/metrics/pairwise/manhattan_test.go
index 8a62a5c..e6361e4 100644
--- a/metrics/pairwise/manhattan_test.go
+++ b/metrics/pairwise/manhattan_test.go
@@ -8,19 +8,34 @@ import (
 )
 
 func TestManhattan(t *testing.T) {
+	var vectorX, vectorY *mat64.Dense
 	manhattan := NewManhattan()
 
 	Convey("Given two vectors", t, func() {
-		vectorX := mat64.NewDense(3, 1, []float64{2, 2, 3})
-		vectorY := mat64.NewDense(3, 1, []float64{1, 4, 5})
+		vectorX = mat64.NewDense(3, 1, []float64{2, 2, 3})
+		vectorY = mat64.NewDense(3, 1, []float64{1, 4, 5})
 
-		Convey("When calculating distance", func() {
+		Convey("When calculating distance with column vectors", func() {
 			result := manhattan.Distance(vectorX, vectorY)
 
 			Convey("The result should be 5", func() {
 				So(result, ShouldEqual, 5)
 			})
+		})
 
+		Convey("When calculating distance with row vectors", func() {
+			vectorX.TCopy(vectorX)
+			vectorY.TCopy(vectorY)
+			result := manhattan.Distance(vectorX, vectorY)
+
+			Convey("The result should be 5", func() {
+				So(result, ShouldEqual, 5)
+			})
+		})
+
+		Convey("When calculating distance with row and column vectors", func() {
+			vectorX.TCopy(vectorX)
+			So(func() { manhattan.Distance(vectorX, vectorY) }, ShouldPanicWith, mat64.ErrShape)
 		})
 
 	})
diff --git a/metrics/pairwise/poly_kernel_test.go b/metrics/pairwise/poly_kernel_test.go
index 67293f5..31f508f 100644
--- a/metrics/pairwise/poly_kernel_test.go
+++ b/metrics/pairwise/poly_kernel_test.go
@@ -8,11 +8,12 @@ import (
 )
 
 func TestPolyKernel(t *testing.T) {
+	var vectorX, vectorY *mat64.Dense
 	polyKernel := NewPolyKernel(3)
 
 	Convey("Given two vectors", t, func() {
-		vectorX := mat64.NewDense(3, 1, []float64{1, 2, 3})
-		vectorY := mat64.NewDense(3, 1, []float64{2, 4, 5})
+		vectorX = mat64.NewDense(3, 1, []float64{1, 2, 3})
+		vectorY = mat64.NewDense(3, 1, []float64{2, 4, 5})
 
 		Convey("When doing inner product", func() {
 			result := polyKernel.InnerProduct(vectorX, vectorY)
diff --git a/metrics/pairwise/rbf_kernel_test.go b/metrics/pairwise/rbf_kernel_test.go
index a8e36d7..dd43082 100644
--- a/metrics/pairwise/rbf_kernel_test.go
+++ b/metrics/pairwise/rbf_kernel_test.go
@@ -8,11 +8,12 @@ import (
 )
 
 func TestRBFKernel(t *testing.T) {
+	var vectorX, vectorY *mat64.Dense
 	rbfKernel := NewRBFKernel(0.1)
 
 	Convey("Given two vectors", t, func() {
-		vectorX := mat64.NewDense(3, 1, []float64{1, 2, 3})
-		vectorY := mat64.NewDense(3, 1, []float64{2, 4, 5})
+		vectorX = mat64.NewDense(3, 1, []float64{1, 2, 3})
+		vectorY = mat64.NewDense(3, 1, []float64{2, 4, 5})
 
 		Convey("When doing inner product", func() {
 			result := rbfKernel.InnerProduct(vectorX, vectorY)