Adding unit tests for argmax functions for Dense and Sparse vectors

Author: George

mllib/src/main/scala/org/apache/spark/mllib/linalg/Vectors.scala

@@ -724,15 +724,22 @@ class SparseVector(
     if (size == 0) {
       -1
     } else {
-      var maxIdx = 0
+      var maxIdx = indices(0)
       var maxValue = values(0)
-      var i = 1
-      foreachActive{ (i, v) =>
-        if(v > maxValue) {
+
+      foreachActive { (i, v) =>
+        if(values(i) > maxValue){
           maxIdx = i
           maxValue = v
         }
       }
+//      while(i < this.indices.size){
+//        if(values(i) > maxValue){
+//          maxIdx = indices(i)
+//          maxValue = values(i)
+//        }
+//        i += 1
+//      }
       maxIdx
     }
   }

mllib/src/test/scala/org/apache/spark/mllib/linalg/VectorsSuite.scala

@@ -42,7 +42,6 @@ class VectorsSuite extends FunSuite {
    val vec = Vectors.dense(arr).asInstanceOf[DenseVector]
     assert(vec.size === arr.length)
     assert(vec.values.eq(arr))
-    vec.argmax
   }
 
   test("sparse vector construction") {
@@ -57,20 +56,38 @@ class VectorsSuite extends FunSuite {
     assert(vec.size === n)
     assert(vec.indices === indices)
     assert(vec.values === values)
-    val vec2 = Vectors.sparse(5,Array(0,3),values).asInstanceOf[SparseVector]
-    vec2.foreachActive( (i, v) => println(i,v))
   }
 
   test("dense to array") {
     val vec = Vectors.dense(arr).asInstanceOf[DenseVector]
     assert(vec.toArray.eq(arr))
   }
 
+  test("dense argmax"){
+    val vec = Vectors.dense(Array.empty[Double]).asInstanceOf[DenseVector]
+    val noMax = vec.argmax
+    assert(noMax === -1)
+
+    val vec2 = Vectors.dense(arr).asInstanceOf[DenseVector]
+    val max = vec2.argmax
+    assert(max === 3)
+  }
+
   test("sparse to array") {
     val vec = Vectors.sparse(n, indices, values).asInstanceOf[SparseVector]
     assert(vec.toArray === arr)
   }
 
+  test("sparse argmax"){
+    val vec = Vectors.sparse(0,Array.empty[Int],Array.empty[Double]).asInstanceOf[SparseVector]
+    val noMax = vec.argmax
+    assert(noMax === -1)
+
+    val vec2 = Vectors.sparse(n,indices,values).asInstanceOf[SparseVector]
+    val max = vec2.argmax
+    assert(max === 3)
+  }
+
   test("vector equals") {
     val dv1 = Vectors.dense(arr.clone())
     val dv2 = Vectors.dense(arr.clone())