Analysis of the advantage given by bunkers

BunkerAdvantage.ipynb

roller.py

import random

def dieroll(n):
    """Roll an n-sided die and return result"""
    return int(random.random() * n) + 1

def roll_once(
    a_army, d_army, a_dice=None, d_dice=None, firepower=False, ambush=False,
    double_casualties=False, bunker=False, atkrad=False, dfndrad=False
):
    # bail if the attacker or defender doesn't have enough guys to roll
    if a_army < 2 or d_army < 1:
        return (a_army, d_army)
    
    a_dice_requested = a_dice
    d_dice_requested = d_dice

    # figure out how many dice are allowed
    a_dice_modifier = 0
    if firepower:
        a_dice_modifier += 1
    if atkrad:
        a_dice_modifier -= 1
    a_dice = min(a_army - 1, 3) + a_dice_modifier
    if a_dice == 0:
        return (a_army, d_army)
    
    d_dice_modifier = 0
    if bunker:
        d_dice_modifier += 1
    if dfndrad:
        d_dice_modifier -= 1
    d_dice = min(d_army, 2) + d_dice_modifier
    if d_dice == 0:
        return (a_army, d_army)

    # if the user has requested an allowable amount of dice, set it
    if 0 < a_dice_requested <= a_dice:
        a_dice = a_dice_requested
    if 0 < d_dice_requested <= d_dice:
        d_dice = d_dice_requested

    # roll the dice
    a_rolls = sorted([dieroll(6) for i in xrange(a_dice)])
    d_rolls = sorted([dieroll(6) for i in xrange(d_dice)])

    # figure out the number of casualties.  Should be equal to the minimum
    # amount of dice rolled.  However, defender casualties are capped at 2 b/c
    # the bonus die from the bunker doesn't count toward their possible losses.
    num_casualties = min( a_dice, min(d_dice, 2) )
    for i in xrange(num_casualties):
        if ambush:
            a_wins = a_rolls[-1] >= d_rolls[-1]
        else:
            a_wins = a_rolls[-1] > d_rolls[-1]

        if a_wins:
            if double_casualties:
                d_army -= 2
            else:
                d_army -= 1
        else:
            a_army -= 1

        a_rolls.pop()
        d_rolls.pop()
        
    return (a_army, d_army)