dice

A Scala library for statistical modelling and analyzing probability distributions. Provides the type Dice which has a rich algebra for combining die rolls.

While this is not primarily for generating random numbers with dice, it does allow you to sample the distributions to "roll" the dice.

Examples:

• 3 d 6 represents a roll of three 6-sided dice.
• d(20) + 5 is a 20-sided die with 5 added to the result.
• d(6) + d(4) adds a 6-sided die to a 4-sided one.
• d(8) * d(2) is an 8-sided die which is multiplied by 2 if a coin comes up heads.
• (8 d 6) / 2 is half the result of eight six-sided dice.
• d(6) reroll (_ < 2) is a six-sided die, rerolling if it's 1, but keeping the reroll.
• d(6) reroll (_ < 2) repeat 8 is 8d6 rerolling any 1s.
• d(20) map (x => if (x == 1) 20 else x) is a 20-sided die, treating rolls of 1 as 20.
• d(6) flatMap (_ d 6) rolls a number of dice determined by a die roll.
• d(100) flatMap (1 d _) rolls a die whose number of sides is determined by a 100-sided die.

If roll:Dice, then:

• roll.probabilities gives you the probability distribution.
• roll.sample actually rolls the dice and gives you a random result.