From 712cb8881cee541e74f307c67c0c34f2170cb3e2 Mon Sep 17 00:00:00 2001
From: Xiangrui Meng <meng@databricks.com>
Date: Wed, 19 Mar 2014 17:06:47 -0700
Subject: [PATCH] make Vectors.sparse Java friendly

rename VectorSuite to VectorsSuite
---
 .../apache/spark/mllib/linalg/Vectors.scala   | 21 +++++++++++++++----
 .../{VectorSuite.scala => VectorsSuite.scala} | 11 +++++++++-
 2 files changed, 27 insertions(+), 5 deletions(-)
 rename mllib/src/test/scala/org/apache/spark/mllib/linalg/{VectorSuite.scala => VectorsSuite.scala} (81%)

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 c102084caa997..16a19df4472f4 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
@@ -17,6 +17,10 @@
 
 package org.apache.spark.mllib.linalg
 
+import java.lang.{Iterable => JavaIterable}
+
+import scala.collection.JavaConverters._
+
 import breeze.linalg.{Vector => BreezeVector, DenseVector => BreezeDenseVector,
   SparseVector => BreezeSparseVector}
 
@@ -68,11 +72,11 @@ object Vectors {
    * @param size vector size.
    * @param elements vector elements in (index, value) pairs.
    */
-  def sparse(size: Int, elements: Iterable[(Int, Double)]): Vector = {
+  def sparse(size: Int, elements: Seq[(Int, Double)]): Vector = {
 
     require(size > 0)
 
-    val (indices, values) = elements.toArray.sortBy(_._1).unzip
+    val (indices, values) = elements.sortBy(_._1).unzip
     var prev = -1
     indices.foreach { i =>
       require(prev < i, "Found duplicate indices: " + i)
@@ -83,14 +87,23 @@ object Vectors {
     new SparseVector(size, indices.toArray, values.toArray)
   }
 
+  /**
+   * Creates a sparse vector using unordered (index, value) pairs.
+   *
+   * @param size vector size.
+   * @param elements vector elements in (index, value) pairs.
+   */
+  def sparse(size: Int, elements: JavaIterable[(Int, Double)]): Vector =
+    sparse(size, elements.asScala.toSeq)
+
   /**
    * Creates a vector instance from a breeze vector.
    */
   private[mllib] def fromBreeze(breezeVector: BreezeVector[Double]): Vector = {
     breezeVector match {
       case v: BreezeDenseVector[Double] => {
-        require(v.offset == 0)
-        require(v.stride == 1)
+        require(v.offset == 0, s"Do not support non-zero offset ${v.offset}.")
+        require(v.stride == 1, s"Do not support stride other than 1, but got ${v.stride}.")
         new DenseVector(v.data)
       }
       case v: BreezeSparseVector[Double] => {
diff --git a/mllib/src/test/scala/org/apache/spark/mllib/linalg/VectorSuite.scala b/mllib/src/test/scala/org/apache/spark/mllib/linalg/VectorsSuite.scala
similarity index 81%
rename from mllib/src/test/scala/org/apache/spark/mllib/linalg/VectorSuite.scala
rename to mllib/src/test/scala/org/apache/spark/mllib/linalg/VectorsSuite.scala
index e3ee97121f822..adf2005b84f1d 100644
--- a/mllib/src/test/scala/org/apache/spark/mllib/linalg/VectorSuite.scala
+++ b/mllib/src/test/scala/org/apache/spark/mllib/linalg/VectorsSuite.scala
@@ -17,9 +17,11 @@
 
 package org.apache.spark.mllib.linalg
 
+import scala.collection.JavaConverters._
+
 import org.scalatest.FunSuite
 
-class VectorSuite extends FunSuite {
+class VectorsSuite extends FunSuite {
 
   val arr = Array(0.1, 0.2, 0.3, 0.4)
   val n = 20
@@ -45,4 +47,11 @@ class VectorSuite extends FunSuite {
     assert(vec.indices === indices)
     assert(vec.values === values)
   }
+
+  test("sparse vector construction with unordered elements stored as Java Iterable") {
+    val vec = Vectors.sparse(n, indices.toSeq.zip(values).reverse.asJava).asInstanceOf[SparseVector]
+    assert(vec.size === n)
+    assert(vec.indices === indices)
+    assert(vec.values === values)
+  }
 }