Dadi

dice.rb

require 'pp'

dice  = [0, 0, 1, 2, 3, 4]
throws  = dice.product(dice, dice, dice, dice)
counts  = throws.inject(Hash.new(0)) { |t, p| t[p.inject(&:+)] += 1; t }
pp counts.map { |(k, v)| [k, (v.fdiv(throws.length) * 100).round(3)] }

dice.rs

#![feature(core)]
use std::collections::BTreeMap;
use std::iter::AdditiveIterator;

fn v_product<'a, T: Clone>(ref x: &'a [T], ref y: &'a [T]) -> Vec<Vec<T>> {
  let mut result = vec![];
  for _x in x.iter() {
    for _y in y.iter() {
      result.push(vec![_x.clone(), _y.clone()]);
    }
  }
  result
}

fn n_product<'a, T: Clone>(ref x: Vec<Vec<T>>, ref y: &'a [T]) -> Vec<Vec<T>> {
  let mut result = vec![];
  for _x in x.iter() {
    for _y in y.iter() {
      let mut _z = _x.clone();
      _z.push(_y.clone());
      result.push(_z);
    }
  }
  result
}

fn main() {
  let dice   = &[0, 0, 1, 2, 3, 4];
  let throws = n_product(n_product(n_product(v_product(dice, dice), dice), dice), dice);
  let mut counts = BTreeMap::<usize, usize>::new();

  for t in throws.iter() {
    let k = t.iter().cloned().sum();

    let c = match counts.get(&k) {
      None    => 1,
      Some(x) => *x + 1
    };
    counts.insert(k, c);
  }
  for (c, v) in counts.iter() {
    println!("{}: {}", c, (*v as f32) / (throws.len() as f32) * 100.0);
  }
}

results.txt

[[0, 0.412],
 [1, 1.029],
 [2, 2.058],
 [3, 3.601],
 [4, 5.787],
 [5, 7.729],
 [6, 9.581],
 [7, 10.995],
 [8, 11.638],
 [9, 11.124],
 [10, 10.044],
 [11, 8.423],
 [12, 6.494],
 [13, 4.565],
 [14, 3.022],
 [15, 1.813],
 [16, 0.965],
 [17, 0.45],
 [18, 0.193],
 [19, 0.064],
 [20, 0.013]]