Merge branch 'master' into mos-bt

13 files changed, 642 insertions, 0 deletions

diff --git a/examples/src/main/scala/spark/examples/BroadcastTest.scala b/examples/src/main/scala/spark/examples/BroadcastTest.scala
new file mode 100644
index 0000000000..f3a173b183
--- /dev/null
+++ b/examples/src/main/scala/spark/examples/BroadcastTest.scala
@@ -0,0 +1,25 @@
+package spark.examples
+
+import spark.SparkContext
+
+object BroadcastTest {
+  def main(args: Array[String]) {
+    if (args.length == 0) {
+      System.err.println("Usage: BroadcastTest <host> [<slices>] [numElem]")
+      System.exit(1)
+    }  
+    
+    val spark = new SparkContext(args(0), "Broadcast Test")
+    val slices = if (args.length > 1) args(1).toInt else 2
+    val num = if (args.length > 2) args(2).toInt else 1000000
+
+    var arr1 = new Array[Int](num)
+    for (i <- 0 until arr1.length) 
+      arr1(i) = i
+    
+    val barr1 = spark.broadcast(arr1)
+    spark.parallelize(1 to 10, slices).foreach {
+      i => println(barr1.value.size)
+    }
+  }
+}
diff --git a/examples/src/main/scala/spark/examples/CpuHog.scala b/examples/src/main/scala/spark/examples/CpuHog.scala
new file mode 100644
index 0000000000..94b3709850
--- /dev/null
+++ b/examples/src/main/scala/spark/examples/CpuHog.scala
@@ -0,0 +1,26 @@
+package spark.examples
+
+import spark._
+
+object CpuHog {
+  def main(args: Array[String]) {
+    if (args.length != 3) {
+      System.err.println("Usage: CpuHog <master> <tasks> <threads_per_task>");
+      System.exit(1)
+    }
+    val sc = new SparkContext(args(0), "CPU hog")
+    val tasks = args(1).toInt
+    val threads = args(2).toInt
+    def task {
+      for (i <- 0 until threads-1) {
+        new Thread() {
+          override def run {
+            while(true) {}
+          }
+        }.start()
+      }
+      while(true) {}
+    }
+    sc.runTasks(Array.make(tasks, () => task))
+  }
+}
diff --git a/examples/src/main/scala/spark/examples/HdfsTest.scala b/examples/src/main/scala/spark/examples/HdfsTest.scala
new file mode 100644
index 0000000000..072b4ce417
--- /dev/null
+++ b/examples/src/main/scala/spark/examples/HdfsTest.scala
@@ -0,0 +1,18 @@
+package spark.examples
+
+import spark._
+
+object HdfsTest {
+  def main(args: Array[String]) {
+    val sc = new SparkContext(args(0), "HdfsTest")
+    val file = sc.textFile(args(1))
+    val mapped = file.map(s => s.length).cache()
+    for (iter <- 1 to 10) {
+      val start = System.currentTimeMillis()
+      for (x <- mapped) { x + 2 }
+      //  println("Processing: " + x)
+      val end = System.currentTimeMillis()
+      println("Iteration " + iter + " took " + (end-start) + " ms")
+    }
+  }
+}
diff --git a/examples/src/main/scala/spark/examples/LocalALS.scala b/examples/src/main/scala/spark/examples/LocalALS.scala
new file mode 100644
index 0000000000..10360dab3d
--- /dev/null
+++ b/examples/src/main/scala/spark/examples/LocalALS.scala
@@ -0,0 +1,121 @@
+package spark.examples
+
+import java.util.Random
+import scala.math.sqrt
+import cern.jet.math._
+import cern.colt.matrix._
+import cern.colt.matrix.linalg._
+
+object LocalALS {
+  // Parameters set through command line arguments
+  var M = 0 // Number of movies
+  var U = 0 // Number of users
+  var F = 0 // Number of features
+  var ITERATIONS = 0
+
+  val LAMBDA = 0.01 // Regularization coefficient
+
+  // Some COLT objects
+  val factory2D = DoubleFactory2D.dense
+  val factory1D = DoubleFactory1D.dense
+  val algebra = Algebra.DEFAULT
+  val blas = SeqBlas.seqBlas
+
+  def generateR(): DoubleMatrix2D = {
+    val mh = factory2D.random(M, F)
+    val uh = factory2D.random(U, F)
+    return algebra.mult(mh, algebra.transpose(uh))
+  }
+
+  def rmse(targetR: DoubleMatrix2D, ms: Array[DoubleMatrix1D],
+    us: Array[DoubleMatrix1D]): Double =
+  {
+    val r = factory2D.make(M, U)
+    for (i <- 0 until M; j <- 0 until U) {
+      r.set(i, j, blas.ddot(ms(i), us(j)))
+    }
+    //println("R: " + r)
+    blas.daxpy(-1, targetR, r)
+    val sumSqs = r.aggregate(Functions.plus, Functions.square)
+    return sqrt(sumSqs / (M * U))
+  }
+
+  def updateMovie(i: Int, m: DoubleMatrix1D, us: Array[DoubleMatrix1D],
+    R: DoubleMatrix2D) : DoubleMatrix1D =
+  {
+    val XtX = factory2D.make(F, F)
+    val Xty = factory1D.make(F)
+    // For each user that rated the movie
+    for (j <- 0 until U) {
+      val u = us(j)
+      // Add u * u^t to XtX
+      blas.dger(1, u, u, XtX)
+      // Add u * rating to Xty
+      blas.daxpy(R.get(i, j), u, Xty)
+    }
+    // Add regularization coefs to diagonal terms
+    for (d <- 0 until F) {
+      XtX.set(d, d, XtX.get(d, d) + LAMBDA * U)
+    }
+    // Solve it with Cholesky
+    val ch = new CholeskyDecomposition(XtX)
+    val Xty2D = factory2D.make(Xty.toArray, F)
+    val solved2D = ch.solve(Xty2D)
+    return solved2D.viewColumn(0)
+  }
+
+  def updateUser(j: Int, u: DoubleMatrix1D, ms: Array[DoubleMatrix1D],
+    R: DoubleMatrix2D) : DoubleMatrix1D =
+  {
+    val XtX = factory2D.make(F, F)
+    val Xty = factory1D.make(F)
+    // For each movie that the user rated
+    for (i <- 0 until M) {
+      val m = ms(i)
+      // Add m * m^t to XtX
+      blas.dger(1, m, m, XtX)
+      // Add m * rating to Xty
+      blas.daxpy(R.get(i, j), m, Xty)
+    }
+    // Add regularization coefs to diagonal terms
+    for (d <- 0 until F) {
+      XtX.set(d, d, XtX.get(d, d) + LAMBDA * M)
+    }
+    // Solve it with Cholesky
+    val ch = new CholeskyDecomposition(XtX)
+    val Xty2D = factory2D.make(Xty.toArray, F)
+    val solved2D = ch.solve(Xty2D)
+    return solved2D.viewColumn(0)
+  }
+
+  def main(args: Array[String]) {
+    args match {
+      case Array(m, u, f, iters) => {
+        M = m.toInt
+        U = u.toInt
+        F = f.toInt
+        ITERATIONS = iters.toInt
+      }
+      case _ => {
+        System.err.println("Usage: LocalALS <M> <U> <F> <iters>")
+        System.exit(1)
+      }
+    }
+    printf("Running with M=%d, U=%d, F=%d, iters=%d\n", M, U, F, ITERATIONS);
+    
+    val R = generateR()
+
+    // Initialize m and u randomly
+    var ms = Array.fromFunction(_ => factory1D.random(F))(M)
+    var us = Array.fromFunction(_ => factory1D.random(F))(U)
+
+    // Iteratively update movies then users
+    for (iter <- 1 to ITERATIONS) {
+      println("Iteration " + iter + ":")
+      ms = (0 until M).map(i => updateMovie(i, ms(i), us, R)).toArray
+      us = (0 until U).map(j => updateUser(j, us(j), ms, R)).toArray
+      println("RMSE = " + rmse(R, ms, us))
+      println()
+    }
+  }
+}
diff --git a/examples/src/main/scala/spark/examples/LocalFileLR.scala b/examples/src/main/scala/spark/examples/LocalFileLR.scala
new file mode 100644
index 0000000000..cc14aa7090
--- /dev/null
+++ b/examples/src/main/scala/spark/examples/LocalFileLR.scala
@@ -0,0 +1,38 @@
+package spark.examples
+
+import java.util.Random
+import Vector._
+
+object LocalFileLR {
+  val D = 10   // Numer of dimensions
+  val rand = new Random(42)
+
+  case class DataPoint(x: Vector, y: Double)
+
+  def parsePoint(line: String): DataPoint = {
+    val nums = line.split(' ').map(_.toDouble)
+    return DataPoint(new Vector(nums.slice(1, D+1)), nums(0))
+  }
+
+  def main(args: Array[String]) {
+    val lines = scala.io.Source.fromFile(args(0)).getLines()
+    val points = lines.map(parsePoint _)
+    val ITERATIONS = args(1).toInt
+
+    // Initialize w to a random value
+    var w = Vector(D, _ => 2 * rand.nextDouble - 1)
+    println("Initial w: " + w)
+
+    for (i <- 1 to ITERATIONS) {
+      println("On iteration " + i)
+      var gradient = Vector.zeros(D)
+      for (p <- points) {
+        val scale = (1 / (1 + Math.exp(-p.y * (w dot p.x))) - 1) * p.y
+        gradient +=  scale * p.x
+      }
+      w -= gradient
+    }
+
+    println("Final w: " + w)
+  }
+}
diff --git a/examples/src/main/scala/spark/examples/LocalLR.scala b/examples/src/main/scala/spark/examples/LocalLR.scala
new file mode 100644
index 0000000000..3fd3f88fa8
--- /dev/null
+++ b/examples/src/main/scala/spark/examples/LocalLR.scala
@@ -0,0 +1,43 @@
+package spark.examples
+
+import java.util.Random
+import Vector._
+
+object LocalLR {
+  val N = 10000  // Number of data points
+  val D = 10   // Numer of dimensions
+  val R = 0.7  // Scaling factor
+  val ITERATIONS = 5
+  val rand = new Random(42)
+
+  case class DataPoint(x: Vector, y: Double)
+
+  def generateData = {
+    def generatePoint(i: Int) = {
+      val y = if(i % 2 == 0) -1 else 1
+      val x = Vector(D, _ => rand.nextGaussian + y * R)
+      DataPoint(x, y)
+    }
+    Array.fromFunction(generatePoint _)(N)
+  }
+
+  def main(args: Array[String]) {
+    val data = generateData
+
+    // Initialize w to a random value
+    var w = Vector(D, _ => 2 * rand.nextDouble - 1)
+    println("Initial w: " + w)
+
+    for (i <- 1 to ITERATIONS) {
+      println("On iteration " + i)
+      var gradient = Vector.zeros(D)
+      for (p <- data) {
+        val scale = (1 / (1 + Math.exp(-p.y * (w dot p.x))) - 1) * p.y
+        gradient +=  scale * p.x
+      }
+      w -= gradient
+    }
+
+    println("Final w: " + w)
+  }
+}
diff --git a/examples/src/main/scala/spark/examples/LocalPi.scala b/examples/src/main/scala/spark/examples/LocalPi.scala
new file mode 100644
index 0000000000..9457472f2d
--- /dev/null
+++ b/examples/src/main/scala/spark/examples/LocalPi.scala
@@ -0,0 +1,17 @@
+package spark.examples
+
+import scala.math.random
+import spark._
+import SparkContext._
+
+object LocalPi {
+  def main(args: Array[String]) {
+    var count = 0
+    for (i <- 1 to 100000) {
+      val x = random * 2 - 1
+      val y = random * 2 - 1
+      if (x*x + y*y < 1) count += 1
+    }
+    println("Pi is roughly " + 4 * count / 100000.0)
+  }
+}
diff --git a/examples/src/main/scala/spark/examples/SleepJob.scala b/examples/src/main/scala/spark/examples/SleepJob.scala
new file mode 100644
index 0000000000..02673a5f88
--- /dev/null
+++ b/examples/src/main/scala/spark/examples/SleepJob.scala
@@ -0,0 +1,21 @@
+package spark.examples
+
+import spark._
+
+object SleepJob {
+  def main(args: Array[String]) {
+    if (args.length != 3) {
+      System.err.println("Usage: SleepJob <master> <tasks> <task_duration>");
+      System.exit(1)
+    }
+    val sc = new SparkContext(args(0), "Sleep job")
+    val tasks = args(1).toInt
+    val duration = args(2).toInt
+    def task {
+      val start = System.currentTimeMillis
+      while (System.currentTimeMillis - start < duration * 1000L)
+        Thread.sleep(200)
+    }
+    sc.runTasks(Array.make(tasks, () => task))
+  }
+}
diff --git a/examples/src/main/scala/spark/examples/SparkALS.scala b/examples/src/main/scala/spark/examples/SparkALS.scala
new file mode 100644
index 0000000000..08e0420371
--- /dev/null
+++ b/examples/src/main/scala/spark/examples/SparkALS.scala
@@ -0,0 +1,141 @@
+package spark.examples
+
+import java.io.Serializable
+import java.util.Random
+import scala.math.sqrt
+import cern.jet.math._
+import cern.colt.matrix._
+import cern.colt.matrix.linalg._
+import spark._
+
+object SparkALS {
+  // Parameters set through command line arguments
+  var M = 0 // Number of movies
+  var U = 0 // Number of users
+  var F = 0 // Number of features
+  var ITERATIONS = 0
+
+  val LAMBDA = 0.01 // Regularization coefficient
+
+  // Some COLT objects
+  val factory2D = DoubleFactory2D.dense
+  val factory1D = DoubleFactory1D.dense
+  val algebra = Algebra.DEFAULT
+  val blas = SeqBlas.seqBlas
+
+  def generateR(): DoubleMatrix2D = {
+    val mh = factory2D.random(M, F)
+    val uh = factory2D.random(U, F)
+    return algebra.mult(mh, algebra.transpose(uh))
+  }
+
+  def rmse(targetR: DoubleMatrix2D, ms: Array[DoubleMatrix1D],
+    us: Array[DoubleMatrix1D]): Double =
+  {
+    val r = factory2D.make(M, U)
+    for (i <- 0 until M; j <- 0 until U) {
+      r.set(i, j, blas.ddot(ms(i), us(j)))
+    }
+    //println("R: " + r)
+    blas.daxpy(-1, targetR, r)
+    val sumSqs = r.aggregate(Functions.plus, Functions.square)
+    return sqrt(sumSqs / (M * U))
+  }
+
+  def updateMovie(i: Int, m: DoubleMatrix1D, us: Array[DoubleMatrix1D],
+    R: DoubleMatrix2D) : DoubleMatrix1D =
+  {
+    val U = us.size
+    val F = us(0).size
+    val XtX = factory2D.make(F, F)
+    val Xty = factory1D.make(F)
+    // For each user that rated the movie
+    for (j <- 0 until U) {
+      val u = us(j)
+      // Add u * u^t to XtX
+      blas.dger(1, u, u, XtX)
+      // Add u * rating to Xty
+      blas.daxpy(R.get(i, j), u, Xty)
+    }
+    // Add regularization coefs to diagonal terms
+    for (d <- 0 until F) {
+      XtX.set(d, d, XtX.get(d, d) + LAMBDA * U)
+    }
+    // Solve it with Cholesky
+    val ch = new CholeskyDecomposition(XtX)
+    val Xty2D = factory2D.make(Xty.toArray, F)
+    val solved2D = ch.solve(Xty2D)
+    return solved2D.viewColumn(0)
+  }
+
+  def updateUser(j: Int, u: DoubleMatrix1D, ms: Array[DoubleMatrix1D],
+    R: DoubleMatrix2D) : DoubleMatrix1D =
+  {
+    val M = ms.size
+    val F = ms(0).size
+    val XtX = factory2D.make(F, F)
+    val Xty = factory1D.make(F)
+    // For each movie that the user rated
+    for (i <- 0 until M) {
+      val m = ms(i)
+      // Add m * m^t to XtX
+      blas.dger(1, m, m, XtX)
+      // Add m * rating to Xty
+      blas.daxpy(R.get(i, j), m, Xty)
+    }
+    // Add regularization coefs to diagonal terms
+    for (d <- 0 until F) {
+      XtX.set(d, d, XtX.get(d, d) + LAMBDA * M)
+    }
+    // Solve it with Cholesky
+    val ch = new CholeskyDecomposition(XtX)
+    val Xty2D = factory2D.make(Xty.toArray, F)
+    val solved2D = ch.solve(Xty2D)
+    return solved2D.viewColumn(0)
+  }
+
+  def main(args: Array[String]) {
+    var host = ""
+    var slices = 0
+    args match {
+      case Array(m, u, f, iters, slices_, host_) => {
+        M = m.toInt
+        U = u.toInt
+        F = f.toInt
+        ITERATIONS = iters.toInt
+        slices = slices_.toInt
+        host = host_
+      }
+      case _ => {
+        System.err.println("Usage: SparkALS <M> <U> <F> <iters> <slices> <host>")
+        System.exit(1)
+      }
+    }
+    printf("Running with M=%d, U=%d, F=%d, iters=%d\n", M, U, F, ITERATIONS);
+    val spark = new SparkContext(host, "SparkALS")
+    
+    val R = generateR()
+
+    // Initialize m and u randomly
+    var ms = Array.fromFunction(_ => factory1D.random(F))(M)
+    var us = Array.fromFunction(_ => factory1D.random(F))(U)
+
+    // Iteratively update movies then users
+    val Rc  = spark.broadcast(R)
+    var msc = spark.broadcast(ms)
+    var usc = spark.broadcast(us)
+    for (iter <- 1 to ITERATIONS) {
+      println("Iteration " + iter + ":")
+      ms = spark.parallelize(0 until M, slices)
+                .map(i => updateMovie(i, msc.value(i), usc.value, Rc.value))
+                .toArray
+      msc = spark.broadcast(ms) // Re-broadcast ms because it was updated
+      us = spark.parallelize(0 until U, slices)
+                .map(i => updateUser(i, usc.value(i), msc.value, Rc.value))
+                .toArray
+      usc = spark.broadcast(us) // Re-broadcast us because it was updated
+      println("RMSE = " + rmse(R, ms, us))
+      println()
+    }
+  }
+}
diff --git a/examples/src/main/scala/spark/examples/SparkHdfsLR.scala b/examples/src/main/scala/spark/examples/SparkHdfsLR.scala
new file mode 100644
index 0000000000..4c71fd0845
--- /dev/null
+++ b/examples/src/main/scala/spark/examples/SparkHdfsLR.scala
@@ -0,0 +1,53 @@
+package spark.examples
+
+import java.util.Random
+import scala.math.exp
+import Vector._
+import spark._
+
+object SparkHdfsLR {
+  val D = 10   // Numer of dimensions
+  val rand = new Random(42)
+
+  case class DataPoint(x: Vector, y: Double)
+
+  def parsePoint(line: String): DataPoint = {
+    //val nums = line.split(' ').map(_.toDouble)
+    //return DataPoint(new Vector(nums.slice(1, D+1)), nums(0))
+    val tok = new java.util.StringTokenizer(line, " ")
+    var y = tok.nextToken.toDouble
+    var x = new Array[Double](D)
+    var i = 0
+    while (i < D) {
+      x(i) = tok.nextToken.toDouble; i += 1
+    }
+    return DataPoint(new Vector(x), y)
+  }
+
+  def main(args: Array[String]) {
+    if (args.length < 3) {
+      System.err.println("Usage: SparkHdfsLR <master> <file> <iters>")
+      System.exit(1)
+    }
+    val sc = new SparkContext(args(0), "SparkHdfsLR")
+    val lines = sc.textFile(args(1))
+    val points = lines.map(parsePoint _).cache()
+    val ITERATIONS = args(2).toInt
+
+    // Initialize w to a random value
+    var w = Vector(D, _ => 2 * rand.nextDouble - 1)
+    println("Initial w: " + w)
+
+    for (i <- 1 to ITERATIONS) {
+      println("On iteration " + i)
+      val gradient = sc.accumulator(Vector.zeros(D))
+      for (p <- points) {
+        val scale = (1 / (1 + exp(-p.y * (w dot p.x))) - 1) * p.y
+        gradient +=  scale * p.x
+      }
+      w -= gradient.value
+    }
+
+    println("Final w: " + w)
+  }
+}
diff --git a/examples/src/main/scala/spark/examples/SparkLR.scala b/examples/src/main/scala/spark/examples/SparkLR.scala
new file mode 100644
index 0000000000..d08f5d3f01
--- /dev/null
+++ b/examples/src/main/scala/spark/examples/SparkLR.scala
@@ -0,0 +1,51 @@
+package spark.examples
+
+import java.util.Random
+import scala.math.exp
+import Vector._
+import spark._
+
+object SparkLR {
+  val N = 10000  // Number of data points
+  val D = 10   // Numer of dimensions
+  val R = 0.7  // Scaling factor
+  val ITERATIONS = 5
+  val rand = new Random(42)
+
+  case class DataPoint(x: Vector, y: Double)
+
+  def generateData = {
+    def generatePoint(i: Int) = {
+      val y = if(i % 2 == 0) -1 else 1
+      val x = Vector(D, _ => rand.nextGaussian + y * R)
+      DataPoint(x, y)
+    }
+    Array.fromFunction(generatePoint _)(N)
+  }
+
+  def main(args: Array[String]) {
+    if (args.length == 0) {
+      System.err.println("Usage: SparkLR <host> [<slices>]")
+      System.exit(1)
+    }
+    val sc = new SparkContext(args(0), "SparkLR")
+    val numSlices = if (args.length > 1) args(1).toInt else 2
+    val data = generateData
+
+    // Initialize w to a random value
+    var w = Vector(D, _ => 2 * rand.nextDouble - 1)
+    println("Initial w: " + w)
+
+    for (i <- 1 to ITERATIONS) {
+      println("On iteration " + i)
+      val gradient = sc.accumulator(Vector.zeros(D))
+      for (p <- sc.parallelize(data, numSlices)) {
+        val scale = (1 / (1 + exp(-p.y * (w dot p.x))) - 1) * p.y
+        gradient +=  scale * p.x
+      }
+      w -= gradient.value
+    }
+
+    println("Final w: " + w)
+  }
+}
diff --git a/examples/src/main/scala/spark/examples/SparkPi.scala b/examples/src/main/scala/spark/examples/SparkPi.scala
new file mode 100644
index 0000000000..31c6c5b9b1
--- /dev/null
+++ b/examples/src/main/scala/spark/examples/SparkPi.scala
@@ -0,0 +1,23 @@
+package spark.examples
+
+import scala.math.random
+import spark._
+import SparkContext._
+
+object SparkPi {
+  def main(args: Array[String]) {
+    if (args.length == 0) {
+      System.err.println("Usage: SparkPi <host> [<slices>]")
+      System.exit(1)
+    }
+    val spark = new SparkContext(args(0), "SparkPi")
+    val slices = if (args.length > 1) args(1).toInt else 2
+    var count = spark.accumulator(0)
+    for (i <- spark.parallelize(1 to 100000, slices)) {
+      val x = random * 2 - 1
+      val y = random * 2 - 1
+      if (x*x + y*y < 1) count += 1
+    }
+    println("Pi is roughly " + 4 * count.value / 100000.0)
+  }
+}
diff --git a/examples/src/main/scala/spark/examples/Vector.scala b/examples/src/main/scala/spark/examples/Vector.scala
new file mode 100644
index 0000000000..ea70626e71
--- /dev/null
+++ b/examples/src/main/scala/spark/examples/Vector.scala
@@ -0,0 +1,65 @@
+package spark.examples
+
+@serializable class Vector(val elements: Array[Double]) {
+  def length = elements.length
+  
+  def apply(index: Int) = elements(index)
+
+  def + (other: Vector): Vector = {
+    if (length != other.length)
+      throw new IllegalArgumentException("Vectors of different length")
+    return Vector(length, i => this(i) + other(i))
+  }
+
+  def - (other: Vector): Vector = {
+    if (length != other.length)
+      throw new IllegalArgumentException("Vectors of different length")
+    return Vector(length, i => this(i) - other(i))
+  }
+
+  def dot(other: Vector): Double = {
+    if (length != other.length)
+      throw new IllegalArgumentException("Vectors of different length")
+    var ans = 0.0
+    for (i <- 0 until length)
+      ans += this(i) * other(i)
+    return ans
+  }
+
+  def * ( scale: Double): Vector = Vector(length, i => this(i) *  scale)
+
+  def unary_- = this * -1
+  
+  def sum = elements.reduceLeft(_ + _)
+
+  override def toString = elements.mkString("(", ", ", ")")
+
+}
+
+object Vector {
+  def apply(elements: Array[Double]) = new Vector(elements)
+
+  def apply(elements: Double*) = new Vector(elements.toArray)
+
+  def apply(length: Int, initializer: Int => Double): Vector = {
+    val elements = new Array[Double](length)
+    for (i <- 0 until length)
+      elements(i) = initializer(i)
+    return new Vector(elements)
+  }
+
+  def zeros(length: Int) = new Vector(new Array[Double](length))
+
+  def ones(length: Int) = Vector(length, _ => 1)
+
+  class Multiplier(num: Double) {
+    def * (vec: Vector) = vec * num
+  }
+
+  implicit def doubleToMultiplier(num: Double) = new Multiplier(num)
+
+  implicit object VectorAccumParam extends spark.AccumulatorParam[Vector] {
+    def addInPlace(t1: Vector, t2: Vector) = t1 + t2
+    def zero(initialValue: Vector) = Vector.zeros(initialValue.length)
+  }
+}