Github user jmabuin commented on a diff in the pull request:
https://github.com/apache/spark/pull/13468#discussion_r65574364
--- Diff:
mllib-local/src/main/scala/org/apache/spark/ml/linalg/Vectors.scala ---
@@ -537,6 +537,22 @@ class DenseVector @Since("2.0.0") ( @Since("2.0.0")
val values: Array[Double]) e
maxIdx
}
}
+
+ /**
+ * Function that returns the result of multiply this DenseVector by
another DenseVector.
+ *
+ * @param other The second DenseVector
+ * @return The resulting Double value
+ */
+ def dot(other: DenseVector): Double = {
+ require(this.size == other.size, "DenseVectors dimmensions must be the
same." +
--- End diff --
Yes, it is a call to an existing method. But the BLAS class is private and
you can only call it from the linalg package. If a normal user wants to do a
dot product in the spark-shell or in a Spark program, he/she can not do it. The
same thing happens with the rest of the BLAS functions.
An example:
```
scala> import org.apache.spark.mllib.linalg.BLAS
import org.apache.spark.mllib.linalg.BLAS
scala> import org.apache.spark.mllib.linalg.DenseVector
import org.apache.spark.mllib.linalg.DenseVector
scala> val a = new DenseVector(Array[Double](1,2,3,4))
a: org.apache.spark.mllib.linalg.DenseVector = [1.0,2.0,3.0,4.0]
scala> val b = new DenseVector(Array[Double](1,2,3,4))
b: org.apache.spark.mllib.linalg.DenseVector = [1.0,2.0,3.0,4.0]
scala> BLAS.dot(a,b)
<console>:30: error: object BLAS in package linalg cannot be accessed in
package org.apache.spark.mllib.linalg
BLAS.dot(a,b)
^
scala>
```
Also, as I said, this is my first contribution and I wanted to start with
something simple ;)
PS: Sorry for the typo and indentation.
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