[SPARK-8479] [MLLIB] Add numNonzeros and numActives to linalg.Matrices

Matrices allow zeros to be stored in values. Sometimes a method is handy to check if the numNonZeros are same as number of Active values.

Author: MechCoder <manojkumarsivaraj334@gmail.com>

Closes #6904 from MechCoder/nnz_matrix and squashes the following commits:

252c6b7 [MechCoder] Add to MiMa excludes
e2390f5 [MechCoder] Use count instead of foreach
2f62b2f [MechCoder] Add to MiMa excludes
d6e96ef [MechCoder] [SPARK-8479] Add numNonzeros and numActives to linalg.Matrices

1 files changed, 10 insertions, 0 deletions

diff --git a/mllib/src/test/scala/org/apache/spark/mllib/linalg/MatricesSuite.scala b/mllib/src/test/scala/org/apache/spark/mllib/linalg/MatricesSuite.scala
index 8dbb70f5d1..a270ba2562 100644
--- a/mllib/src/test/scala/org/apache/spark/mllib/linalg/MatricesSuite.scala
+++ b/mllib/src/test/scala/org/apache/spark/mllib/linalg/MatricesSuite.scala
@@ -455,4 +455,14 @@ class MatricesSuite extends SparkFunSuite {
     lines = mat.toString(5, 100).lines.toArray
     assert(lines.size == 5 && lines.forall(_.size <= 100))
   }
+
+  test("numNonzeros and numActives") {
+    val dm1 = Matrices.dense(3, 2, Array(0, 0, -1, 1, 0, 1))
+    assert(dm1.numNonzeros === 3)
+    assert(dm1.numActives === 6)
+
+    val sm1 = Matrices.sparse(3, 2, Array(0, 2, 3), Array(0, 2, 1), Array(0.0, -1.2, 0.0))
+    assert(sm1.numNonzeros === 1)
+    assert(sm1.numActives === 3)
+  }
 }