1 files changed, 139 insertions, 0 deletions
diff --git a/core/src/main/scala/org/apache/spark/util/Vector.scala b/core/src/main/scala/org/apache/spark/util/Vector.scala
new file mode 100644
index 0000000000..fe710c58ac
--- /dev/null
+++ b/core/src/main/scala/org/apache/spark/util/Vector.scala
@@ -0,0 +1,139 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.util
+
+class Vector(val elements: Array[Double]) extends Serializable {
+  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 add(other: Vector) = this + other
+
+  def - (other: Vector): Vector = {
+    if (length != other.length)
+      throw new IllegalArgumentException("Vectors of different length")
+    return Vector(length, i => this(i) - other(i))
+  }
+
+  def subtract(other: Vector) = this - other
+
+  def dot(other: Vector): Double = {
+    if (length != other.length)
+      throw new IllegalArgumentException("Vectors of different length")
+    var ans = 0.0
+    var i = 0
+    while (i < length) {
+      ans += this(i) * other(i)
+      i += 1
+    }
+    return ans
+  }
+
+  /**
+   * return (this + plus) dot other, but without creating any intermediate storage
+   * @param plus
+   * @param other
+   * @return
+   */
+  def plusDot(plus: Vector, other: Vector): Double = {
+    if (length != other.length)
+      throw new IllegalArgumentException("Vectors of different length")
+    if (length != plus.length)
+      throw new IllegalArgumentException("Vectors of different length")
+    var ans = 0.0
+    var i = 0
+    while (i < length) {
+      ans += (this(i) + plus(i)) * other(i)
+      i += 1
+    }
+    return ans
+  }
+
+  def += (other: Vector): Vector = {
+    if (length != other.length)
+      throw new IllegalArgumentException("Vectors of different length")
+    var i = 0
+    while (i < length) {
+      elements(i) += other(i)
+      i += 1
+    }
+    this
+  }
+
+  def addInPlace(other: Vector) = this +=other
+
+  def * (scale: Double): Vector = Vector(length, i => this(i) * scale)
+
+  def multiply (d: Double) = this * d
+
+  def / (d: Double): Vector = this * (1 / d)
+
+  def divide (d: Double) = this / d
+
+  def unary_- = this * -1
+
+  def sum = elements.reduceLeft(_ + _)
+
+  def squaredDist(other: Vector): Double = {
+    var ans = 0.0
+    var i = 0
+    while (i < length) {
+      ans += (this(i) - other(i)) * (this(i) - other(i))
+      i += 1
+    }
+    return ans
+  }
+
+  def dist(other: Vector): Double = math.sqrt(squaredDist(other))
+
+  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: Array[Double] = Array.tabulate(length)(initializer)
+    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 org.apache.spark.AccumulatorParam[Vector] {
+    def addInPlace(t1: Vector, t2: Vector) = t1 + t2
+
+    def zero(initialValue: Vector) = Vector.zeros(initialValue.length)
+  }
+
+}