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import scala.collection.JavaConversions._
object Test {
def main(args:Array[String]) = {
val tests = 5000
val jm: java.util.Map[Int, Int] = scala.collection.mutable.Map((0 until tests) zip (0 until tests).reverse: _*)
val es = jm.entrySet()
val it = es.iterator
// chi square test
val groups = 10
val hits = new Array[Int](groups)
def hit(hc: Int) {
val bucket = math.abs(hc) / (Int.MaxValue / groups)
hits(bucket) += 1
}
def expected = tests / groups
def Dstat = {
val diffs = for (i <- 0 until groups) yield math.abs(hits(i) - expected)
diffs.sum.toDouble / expected
}
def ChiSquare = {
val diffs = for (i <- 0 until groups) yield (hits(i) - expected) * (hits(i) - expected)
diffs.sum.toDouble / expected
}
while (it.hasNext) {
val x = it.next()
hit(x.##)
}
// println(hits.toBuffer)
// println(ChiSquare)
assert(ChiSquare < 4.0, ChiSquare + " -> " + hits.mkString(", "))
}
}
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