Machine Learning with Spark - Second Edition

Matrix operations

There are different kinds of operations which can be performed on matrices.

• Elementwise addition: Given two matrices, a and b, addition of the two (a + b) means adding each element of two matrices.

               Breeze

        val a = DenseMatrix((1,2),(3,4))         val b = DenseMatrix((2,2),(2,2))         val c = a + b         println("a: n" + a)         println("b: n" + b)         println("a + b : n" + c) 

The output of the last code is given as follows:

      a:       1  2        3  4        b:      2  2        2  2        a + b :       3  4        5  6  

• Elementwise multiplication: In this operation, each element of the matrix a is multiplied by matrix

            Breeze

        a :* b          val d = a*b         println("Dot product a*b : n" + d) 

The output of the preceding code is given as follows:

      Dot product a*b : 6 6  ...