Conway's Game of Life¶

import numpy as np from scipy.signal import convolve # used for counting the number of living neighbors each cell has FILTER = np.array([[1, 1, 1], [1, 100, 1], [1, 1, 1]], dtype=np.uint8) 

def evolve(length, generations):  """  Run the Game of Life. Starting state is random.  Parameters  ----------  length : int  Universe will be `length` units per side.  generations : int  Number of generations to run simulation.  """ current = np.random.randint(2, size=(length, length)) next = np.empty_like(current) current[length/2, 1:(length-1)] = 1 show_board(current) for _ in xrange(generations): advance(current, next) current, next = next, current show_board(current) 

def advance(current, next):  """  Calculate the next iteration of the Game of Life.  Parameters  ----------  current : 2D array  Current state of universe.  next : 2D array  This array will be modified in place so that it contains the  next step. Must be the same size as `current`.  """ assert current.shape[0] == current.shape[1], \ 'Expected square universe' next[:] = 0 count = convolve(current, FILTER, mode='same') next[(count == 3) | (count == 102) | (count == 103)] = 1 

from IPython.display import clear_output, display_html import time def show_board(board):  """  Print the current Game of Life universe in an HTML table.  Removes any existing output using `IPython.display.clear_output`  to make an animation. This doesn't scale well beyond ~50x50 boards.  Parameters  ----------  board : 2D array  Array representing the current universe.  """ clear_output() nx, ny = board.shape table = '<table style="border-color: black; border-width: 5px;">\n' for y in xrange(ny-1, -1, -1): table += '<tr>' for x in xrange(0, nx): if board[x, y]: table += '<td style="background: black; border-color: white;"></td>' else: table += '<td style="border-color: white;"></td>' table += '</tr>\n' table += '</table>' display_html(table, raw=True) time.sleep(0.1)