#!/usr/bin/ruby

target = nil
range = nil

if ARGV.size == 1 then
  begin
    range = eval(ARGV[0])
    if range.class != Range then
      raise Exception::new
    end
    target = $stdin
  rescue Exception
    range = nil
    target = open(ARGV[0])
  end
elsif ARGV.size == 2 then
  target = open(ARGV[0])
  range = eval(ARGV[1])
end

unless target then 
  puts "Target not found!!"
  puts "Usage1 : #{__FILE__} log_CSV [range=0..-1]" 
  puts "Usage2 : | #{__FILE__} [range=0..-1]"
  exit
end

data = []
8.times{|i| data << []}
open(ARGV[0]).each_with_index{|line, line_no|
	if range and !range.include?(line_no) then next end
	(line.chop!.split(/,/))[2..-1].each_with_index{|item, i|
		data[i] << item.to_i
	}
}

# ƒÊ,ƒÐ‚ð‹�‚ß‚é
mu = []
sigma2 = []
data.each{|item|
	sum = 0.0
	sum2 = 0.0
	item.each{|v|
		sum += v
		sum2 += v ** 2
	}
	mu << (sum / item.size)
	sigma2 << (sum2 / item.size) - ((sum / item.size) ** 2)
}

mu.size.times{|i|
	puts "Ch#{i}, mu: #{mu[i]}, sigma2: #{sigma2[i]}, sigma: #{Math::sqrt(sigma2[i])}"
}