JavaOne Talk: Performance Comparisons of Dynamic Languages on the Java Virtual Machine

Below are the sldies. Major thanks to Charlie Nutter for great feedback and advice on the Ruby code and tuning JRuby performance. Thanks to Chouser and Timothy Pratley for help with the Clojure code. And major thanks to Brian Frank for help with the Fan code.

Performance Comparisons of Dynamic Languages on the Java Virtual Machine

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JavaOne Talk: Fan Prime Sieve

See this post for an explanation on why this code is being shown and what kind of responses would be useful. See this post for the Java algorithm to compare against.

Note: This solution is courtesy of Mr. Fan himself, Brian Frank. Thanks Brian!

class Primes {
  Int[] primes := Int[,]
  Int size

  new make(Int n) {
    size = n
    primes.capacity = n
    init
  }

  private Void init() {
    i := 2
    max := calcSize
    nums := Bool[,]
    nums.fill(true, max)
    while (i < max && primes.size < size) {
      p := i
      if (nums[i])
      {
        primes.add(p)
        j := 2*p;
        while (j < max - p) {
          nums[j] = false
          j += p;
        }
      }
      i += 1;
    }
  }

   Int last() { primes.last }

   private Int calcSize() {
     max := 2
     while ((max.toFloat/max.toFloat.log).toInt < size && max < 0x7fff_ffff && max > 0) {
        max *=2; // memory inefficient, but fast
     }
     return max;
  }
}