Pebble transfer.py
From Werner KRAUTH
This page presents the program markov_disks_box.py, a Markov-chain algorithm for four disks in a square box of sides 1.
Contents |
Description
Program
import random
L = [[0.25, 0.25], [0.75, 0.25], [0.25, 0.75], [0.75, 0.75]]
sigma = 0.15
sigma_sq = sigma ** 2
delta = 0.1
n_steps = 1000
for steps in range(n_steps):
a = random.choice(L)
b = [a[0] + random.uniform(-delta, delta), a[1] + random.uniform(-delta, delta)]
min_dist = min((b[0] - c[0]) ** 2 + (b[1] - c[1]) ** 2 for c in L if c != a)
box_cond = min(b[0], b[1]) < sigma or max(b[0], b[1]) > 1.0 - sigma
if not (box_cond or min_dist < 4.0 * sigma ** 2):
a[:] = b
print L
Version
See history for version information.
import numpy
neighbor = [[1, 3, 0, 0], [2, 4, 0, 1], [2, 5, 1, 2],
[4, 6, 3, 0], [5, 7, 3, 1], [5, 8, 4, 2],
[7, 6, 6, 3], [8, 7, 6, 4], [8, 8, 7, 5]]
transfer = numpy.zeros((9, 9))
for k in range(9):
for neigh in range(4): transfer[neighbor[k][neigh], k] += 0.25
position = numpy.zeros(9)
position[8] = 1.0
for t in range(100):
print t,' ',["%0.5f" % i for i in position]
position = numpy.dot(transfer, position)
