#!/usr/bin/python
# By Tom Wright
# Use this code however you like...

""" Numpy game of life."""

import numpy

def iterate(board):
    # find number of neighbours that each square has
    neighbour_count = numpy.zeros(board.shape)
    neighbour_count[1:, 1:] += board[:-1, :-1]
    neighbour_count[1:, :-1] += board[:-1, 1:]
    neighbour_count[:-1, 1:] += board[1:, :-1]
    neighbour_count[:-1, :-1] += board[1:, 1:]
    neighbour_count[:-1, :] += board[1:, :]
    neighbour_count[1:, :] += board[:-1, :]
    neighbour_count[:, :-1] += board[:, 1:]
    neighbour_count[:, 1:] += board[:, :-1]
    
    # a live cell is killed if it has fewer 
    # than 2 or more than 3 neighbours.
    part1 = ((board == 1) & (neighbour_count < 4) & (neighbour_count > 1)) 

    # a new cell forms if a square has exactly three members
    part2 = ((board == 0) & (neighbour_count == 3))

    # cast booleans to integers
    new_board = numpy.cast[numpy.int](part1 | part2)
    return new_board



board = numpy.array([
        [0, 1, 0, 0, 0], 
        [0, 0, 1, 1, 0], 
        [0, 1, 1, 0, 0], 
        [0, 0, 0, 0, 0],
        [1, 1, 1, 0, 0]])


for i in range(100):
    print board
    board = iterate(board)