From: martinus <martin.ankerl@...>
Date: 2005-01-28T01:40:59+09:00
Subject: Re: [SUMMARY] Paper Rock Scissors (#16)

> BTW, I'd be interested if anyone found a nicer looking solution to
> do a weighted rand.

What you are doing is called Roulett wheel selection, which is often
used as a selection algorithm when using genetic algorithms. I think
this is a bit nicer:

def choose
# sum up all values
sum = @biases.values.inject(0) {|sum, val| sum + val }
# choose something
search_sum = rand(sum)
# count up until found
current_sum = 0
found = @biases.detect do |key, value|
current_sum += value
current_sum > search_sum
	end
	found[0]
end

martinus