UnitInterval

UnitInterval.scala

  /*
   Operations are allowed on UnitIntervals that violate the closedness
   of the structure, but these violations are not realized until the
   underlying value is determined.
   */
  final class UnitInterval private (private val underlying: Double) {

    def - (other: UnitInterval) =
      new UnitInterval(underlying - other.underlying)

    def + (other: UnitInterval) =
      new UnitInterval(underlying + other.underlying)

    def * (other: UnitInterval): UnitInterval =
      new UnitInterval(underlying * other.underlying)

    def / (other: UnitInterval): UnitInterval =
      new UnitInterval(underlying / other.underlying)

    def negate: UnitInterval =
      new UnitInterval(1.0 - underlying)

    def getOption: Option[Double] =
      if (underlying <= 1.0 && underlying >= 0.0) Some(underlying)
      else None
  }

  object UnitInterval {

    def zero = new UnitInterval(0.0)

    def min(a: UnitInterval, b: UnitInterval) =
      new UnitInterval(math.min(a.underlying, b.underlying))

    def floor(a: UnitInterval) =
      new UnitInterval(math.floor(a.underlying))

    def apply(a: Double): Option[UnitInterval] =
      if (a > 0.0 && a < 1.0) Some(new UnitInterval(a))
      else None

    def b_flat(y: UnitInterval, A: UnitInterval, B: UnitInterval, C: UnitInterval) =
      A +
        min(zero, floor(y - B)) * ((A * (B - y)) / B) -
        min(zero, floor(C - y)) * ((A.negate * (y - C)) / C.negate)
  }