From fb743da7b551972a7b97c3805d9f0b725da0c719 Mon Sep 17 00:00:00 2001
From: Liang-Chi Hsieh <viirya@gmail.com>
Date: Tue, 6 Jan 2015 17:25:08 +0800
Subject: [PATCH] Modified for comment and fix bug.

---
 .../apache/spark/mllib/linalg/Vectors.scala   |  5 +++--
 .../spark/mllib/linalg/VectorsSuite.scala     | 20 +++++++++----------
 2 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/mllib/src/main/scala/org/apache/spark/mllib/linalg/Vectors.scala b/mllib/src/main/scala/org/apache/spark/mllib/linalg/Vectors.scala
index 6a782b079aac3..d40f13342a3d9 100644
--- a/mllib/src/main/scala/org/apache/spark/mllib/linalg/Vectors.scala
+++ b/mllib/src/main/scala/org/apache/spark/mllib/linalg/Vectors.scala
@@ -373,8 +373,9 @@ object Vectors {
     var kv2 = 0
     val indices = v1.indices
     var squaredDistance = 0.0
-    var iv1 = indices(kv1)
+    val nnzv1 = indices.size
     val nnzv2 = v2.size
+    var iv1 = if (nnzv1 > 0) indices(kv1) else -1
    
     while (kv2 < nnzv2) {
       var score = 0.0
@@ -382,7 +383,7 @@ object Vectors {
         score = v2(kv2)
       } else {
         score = v1.values(kv1) - v2(kv2)
-        if (kv1 < indices.length - 1) {
+        if (kv1 < nnzv1 - 1) {
           kv1 += 1
           iv1 = indices(kv1)
         }
diff --git a/mllib/src/test/scala/org/apache/spark/mllib/linalg/VectorsSuite.scala b/mllib/src/test/scala/org/apache/spark/mllib/linalg/VectorsSuite.scala
index 2642521b97765..85ac8ccebfc59 100644
--- a/mllib/src/test/scala/org/apache/spark/mllib/linalg/VectorsSuite.scala
+++ b/mllib/src/test/scala/org/apache/spark/mllib/linalg/VectorsSuite.scala
@@ -178,16 +178,16 @@ class VectorsSuite extends FunSuite {
   }
 
   test("sqdist") {
-    val random = new Random(System.nanoTime())
-    for (m <- 1 until 1000 by 10) {
-      val nnz = random.nextInt(m) + 1
+    val random = new Random()
+    for (m <- 1 until 1000 by 100) {
+      val nnz = random.nextInt(m)
 
-      val indices1 = random.shuffle(0 to m - 1).toArray.slice(0, nnz).sorted
-      val values1 = indices1.map(i => random.nextInt(m + 1) * random.nextDouble())
+      val indices1 = random.shuffle(0 to m - 1).slice(0, nnz).sorted.toArray
+      val values1 = Array.fill(nnz)(random.nextDouble)
       val sparseVector1 = Vectors.sparse(m, indices1, values1)
 
-      val indices2 = random.shuffle(0 to m - 1).toArray.slice(0, nnz).sorted
-      val values2 = indices2.map(i => random.nextInt(m + 1) * random.nextDouble())
+      val indices2 = random.shuffle(0 to m - 1).slice(0, nnz).sorted.toArray
+      val values2 = Array.fill(nnz)(random.nextDouble)
       val sparseVector2 = Vectors.sparse(m, indices2, values2)
 
       val denseVector1 = Vectors.dense(sparseVector1.toArray)
@@ -196,11 +196,11 @@ class VectorsSuite extends FunSuite {
       val squaredDist = breezeSquaredDistance(sparseVector1.toBreeze, sparseVector2.toBreeze)
 
       // SparseVector vs. SparseVector 
-      assert(Vectors.sqdist(sparseVector1, sparseVector2) === squaredDist) 
+      assert(Vectors.sqdist(sparseVector1, sparseVector2) ~== squaredDist relTol 1E-8) 
       // DenseVector  vs. SparseVector
-      assert(Vectors.sqdist(denseVector1, sparseVector2) === squaredDist)
+      assert(Vectors.sqdist(denseVector1, sparseVector2) ~== squaredDist relTol 1E-8)
       // DenseVector  vs. DenseVector
-      assert(Vectors.sqdist(denseVector1, denseVector2) === squaredDist)
+      assert(Vectors.sqdist(denseVector1, denseVector2) ~== squaredDist relTol 1E-8)
     }    
   }