bench/shootout/moments.ruby

   1 #!/usr/bin/ruby
   2 # -*- mode: ruby -*-
   3 # $Id: moments.ruby,v 1.2 2005-06-10 00:57:22 igouy-guest Exp $
   4 # http://www.bagley.org/~doug/shootout/
   5
   6 # throw away unused parameter sent by benchmark framework
   7 ARGV.shift()
   8
   9 def main ()
  10     sum = 0.0
  11     nums = []
  12     num = nil
  13
  14     for line in STDIN.readlines()
  15         num = Float(line)
  16         nums << num
  17         sum += num
  18     end
  19
  20     n = nums.length()
  21     mean = sum/n;
  22     deviation = 0.0
  23     average_deviation = 0.0
  24     standard_deviation = 0.0
  25     variance = 0.0
  26     skew = 0.0
  27     kurtosis = 0.0
  28
  29     for num in nums
  30         deviation = num - mean
  31         average_deviation += deviation.abs()
  32         variance += deviation**2;
  33         skew += deviation**3;
  34         kurtosis += deviation**4
  35     end
  36     average_deviation /= n
  37     variance /= (n - 1)
  38     standard_deviation = Math.sqrt(variance)
  39
  40     if (variance > 0.0)
  41         skew /= (n * variance * standard_deviation)
  42         kurtosis = kurtosis/(n * variance * variance) - 3.0
  43     end
  44
  45     nums.sort()
  46     mid = n / 2
  47
  48     if (n % 2) == 0
  49         median = (nums.at(mid) + nums.at(mid-1))/2
  50     else
  51         median = nums.at(mid)
  52     end
  53
  54     printf("n:                  %d\n", n)
  55     printf("median:             %f\n", median)
  56     printf("mean:               %f\n", mean)
  57     printf("average_deviation:  %f\n", average_deviation)
  58     printf("standard_deviation: %f\n", standard_deviation)
  59     printf("variance:           %f\n", variance)
  60     printf("skew:               %f\n", skew)
  61     printf("kurtosis:           %f\n", kurtosis)
  62 end
  63
  64 main()