singleThreadedMultiplicationFAST

gistfile1.scala

  @inline def singleThreadedMultiplicationFAST(m1:Seq[Array[Double]], m2:Array[Array[Double]] ) ={
    val res =  Array.ofDim[Double](m1.length, m2(0).length)
    val M1_COLS = m1(0).length
    val M1_ROWS = m1.length
    val M2_COLS = m2(0).length

    var col, i  = 0
    var sum = 0.0
    var row = 0

    while(row < M1_ROWS){ col = 0
      while(col < M2_COLS){ i = 0; sum = 0
        while(i<M1_COLS){
          // calculating the sum in a variable seems to be faster than updating the array all the time
          sum += m1(row)(i) * m2(i)(col)
          i+=1
        }
        res(row)(col) = sum 
        col += 1

      }; row += 1
    }
    res
  }