This shows two different timing applications that I used for timing some N-body simulations in Scala.

MainTiming.scala

object MainTiming extends App {
	def timeCode[T](warmups: Int, timeRuns: Int)(body: => T): Seq[Double] = {
		for(_ <- 1 to warmups) body
		for(_ <- 1 to timeRuns) yield {
			val start = System.nanoTime()
			body
			(System.nanoTime()-start)*1e-9
		}
	}
	def printTimeInfo(times: Seq[Double]): Unit = {
		val mean = times.sum/times.length
		val rms = math.sqrt(times.map(x => (x-mean)*(x-mean)).sum/times.length)
		println(s"mean = $mean, rms = $rms")
	}

	val numBodies = 1000
	val dt = 0.01
	NBodyValClass.initArrays(numBodies, dt)
	println("Value Type:")
	printTimeInfo(timeCode(5,20){ NBodyValClass.forSim(100) })
	val mutSim = new NBodyMutableClass(numBodies, dt)
	println("Mutable Class:")
	printTimeInfo(timeCode(5,20){ mutSim.forSim(100) })
	val immutSim = new NBodyImmutableClass(numBodies, dt)
	println("Immutable Class:")
	printTimeInfo(timeCode(5,20){ immutSim.forSim(100) })
	val funcBodies = NBodyFunctional.initBodies(numBodies)
	println("Functional 1:")
	printTimeInfo(timeCode(5,20){ NBodyFunctional.forSim(funcBodies,100,dt) })
	println("Functional 2:")
	printTimeInfo(timeCode(5,20){ NBodyFunctional.forSim2(funcBodies,100,dt) })
}

object SimpleTiming extends App {
	val numBodies = 1000
	val dt = 0.01
	NBodyValClass.initArrays(numBodies, dt)
	val start = System.nanoTime()
	NBodyValClass.forSim(1000)
	println((System.nanoTime()-start)*1e-9)
}