How it works...

1. The signature for this method constructor is:

DenseVector (double[] values)

1. The method inherits from the following which makes its concrete methods available to all routines:

interface class java.lang.Object
interface org.apache.spark.mllib.linalg. Vector

1. There are several method calls that are of interest:
   1. Make a deep copy of the vector:

DenseVector copy()

1. 1. Convert to the SparseVector. You will do this if your vector is long and the density decreases after a number of operations (for example, zero out non-contributing members):

SparseVector toSparse()

1. 1. Find the number of non-zero elements. This is useful so you can convert on-the-fly to the SparseVector if the density ID is low:

Int numNonzeros()

• 1. Convert the vector to the array. This is often necessary when dealing with distributed operations that require close interactions with RDDs or proprietary algorithms that use Spark ML as a subsystem:

Double[] toArray()