Normalizer. Takes any TraversableLike collection of Numeric values and returns those values normalized as Double between 0 and 1.

Normalizer.scala

import scala.collection.generic.CanBuildFrom
import scala.collection.TraversableLike
implicit class Normalizer[N:Numeric, M[+_]](xs:M[N]) {
  def normalize(implicit bf: CanBuildFrom[M[N], Double, M[Double]], 
                ev: M[N] => TraversableLike[N, M[N]], 
                eb: M[Double] => TraversableLike[Double, M[Double]]) = {
    val n = implicitly[Numeric[N]]
    val mind = n.toDouble(xs.min)
    val maxd = n.toDouble(xs.max)
    xs.map(v => (n.toDouble(v) - mind) * (1 / (maxd - mind)))
  }
}

Could do Spire Rationals thus : (n.b. imports for Rationals are required)

import scala.collection.generic.CanBuildFrom
import scala.collection.TraversableLike
implicit class NormalizeRationalM[+_] {
def normalize(implicit bf: CanBuildFrom[M[Rational], Rational, M[Rational]],
ev: M[Rational] => TraversableLike[Rational, M[Rational]]) = {
val minr = xs.min
val maxr = xs.max
xs.map(v => (v - minr) * (r"1" / (maxr - minr)))
}
}