DualNumbers

DualNumbers.scala

package model

case class DualNumbers(a: Double = 0d, b: Double = 0d) {

  def + : DualNumbers = this

  def - : DualNumbers = DualNumbers(-a, -b)

  def <(rhs: DualNumbers): DualNumbers = this < rhs

  def ++ : DualNumbers = DualNumbers(a + 1, b)

  def -- : DualNumbers = DualNumbers(a - 1, b)

  def +=(rhs: DualNumbers): DualNumbers =
    DualNumbers(a + rhs.a, b + rhs.b)

  def +=(rhs: Double): DualNumbers = this.copy(a = this.a + rhs)

  def -=(rhs: DualNumbers): DualNumbers =
    DualNumbers(a - rhs.a, b - rhs.b)

  def -=(rhs: Double): DualNumbers = this.copy(a = this.a - rhs)

  def *=(rhs: DualNumbers): DualNumbers = {
    val _b = {
      var ret = this.b * rhs.a
      ret = ret + (this.a * rhs.b)
      ret = ret * rhs.a
      ret
    }
    val _a = this.a * rhs.a
    DualNumbers(_a, _b)
  }

  def *=(rhs: Double): DualNumbers =
    DualNumbers(a * rhs, b * rhs)

  def /=(rhs: DualNumbers): DualNumbers = {
    val _b = {
      var ret = this.b * rhs.a
      ret = ret - (this.a * rhs.b)
      ret = ret / (rhs.a * rhs.a)
      ret
    }
    val _a = this.a / rhs.a
    DualNumbers(_a, _b)
  }

  def /=(rhs: Double): DualNumbers =
    DualNumbers(a / rhs, b / rhs)

  /**
	 * 現在の値をその逆数にする
	 * @return [[DualNumbers]]
	 */
  def inverse(): DualNumbers = {
    assert(a != 0d)
    val _a = 1d / a
    val _b = b / -(a * a)
    DualNumbers(_a, _b)
  }

  /**
	 * 現在の値をその共役にする
	 * @return [[DualNumbers]]
	 */
  def conjugate(): DualNumbers = this.copy(b = -b)
}

object DualNumbers {

  /**
	 * 双対数の零元
	 * @return [[DualNumbers]]
	 */
  def zero(): DualNumbers = DualNumbers()

  /**
	 * 双対数の加法単位元
	 * @return [[DualNumbers]]
	 */
  def additiveIdentity(): DualNumbers = zero()

  /**
	 * 双対数の乗法単位元
	 * @return [[DualNumbers]]
	 */
  def multiplicativeIdentity(): DualNumbers = zero()

  implicit def orderingDefinition: Ordering[DualNumbers] =
    Ordering.by(e => (e.a, e.b))
}