// Vector length
def vecLength(implicit values: List[Double]) = pow(values.sum, .5)

// Radial basis function
def rbf(v1: List[Double], v2: List[Double], gamma:Int = 20) = {
     val dv = { for(i <- (1 to v1.length)) yield (v1(i)-v2(i)) }.toList
     val l = vecLength(dv)
     pow(scala.math.E, (-gamma*l))
}