Scala v/s Kotlin

test.kts

var count = 0
var totalTime = 0L

fun test() {
  val start = System.currentTimeMillis()

  val x = (1L..5000000L) map {it * 40} reduce {a,b -> (a*b)%19 + 1}

  val end = System.currentTimeMillis()

  val timeTaken = (end - start)
  totalTime += timeTaken

  println("answer is: " + x)
  println("     time: " + timeTaken + " ms")

  count += 1
}

test()
test()
test()
test()
test()

test()
test()
test()
test()
test()
  
println("Avg time: " + (totalTime.toDouble() / count))

test.scala

var count = 0
var totalTime = 0L

def test() {
  val start = System.currentTimeMillis()
  val x = (1L to 5000000L) map {_ * 40} reduce {(a,b) => (a*b)%19 + 1}
  val end = System.currentTimeMillis()

  val timeTaken = (end - start)
  totalTime += timeTaken

  println("answer is: " + x)
  println("     time: " + timeTaken + " ms")

  count += 1
}

test()
test()
test()
test()
test()

test()
test()
test()
test()
test()

println("Avg time: " + (totalTime.toDouble / count))

Benchmark results

Kotlin

$ kotlinc -version
INFO: Kotlin Compiler version 0.10.195

$kotlinc -script test.kts
Avg time: 3763.3333333333335 ms

Scala

$ scala -version
Scala code runner version 2.11.5 -- Copyright 2002-2013, LAMP/EPFL

$ scala test.scala
Avg time: 478.5 ms

I got different result from yours. Kotlin version is much faster than Scala.

Java 1.8.0_31 Mac 10.9.5
Kotlin:
Avg time: 171.2

Scala 2.11.5
Avg time: 649.7857142857143

JRE 1.8.0_60

	Scala	Kotlin	Java
Version	2.11.7	0.13.1513	1.8.0
Avg time	393ms	530ms	35ms
Avg after warmup	200ms	220ms	30ms

Java version:

long x = LongStream.rangeClosed(1l, 5000000l)
        .map(n -> n * 40)
        .reduce((a, b) ->  (a * b) % 19 + 1)
        .getAsLong();

In Scala you should do (1 to 1000000).view that turns it lazy.