Thermo ising.py
From Werner KRAUTH
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+ | This page presents the program markov_disks_box.py, a Markov-chain algorithm for four disks in a square box of sides 1. | ||
+ | |||
+ | __FORCETOC__ | ||
+ | =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. | ||
+ | |||
+ | [[Category:Python]] | ||
+ | |||
+ | |||
import math, os | import math, os | ||
Revision as of 21:39, 22 September 2015
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 math, os L = 6 N = L * L filename = 'data_dos_L%i.txt' % L if os.path.isfile(filename): dos = {} f = open(filename, 'r') for line in f: E, N_E = line.split() dos[int(E)] = int(N_E) f.close() else: exit('input file missing') list_T = [0.5 + 0.5 * i for i in range(10)] for T in list_T: Z = 0.0 E_av = 0.0 M_av = 0.0 E2_av = 0.0 for E in dos.keys(): weight = math.exp(- E / T) * dos[E] Z += weight E_av += weight * E E2_av += weight * E ** 2 E2_av /= Z E_av /= Z cv = (E2_av - E_av ** 2) / N / T ** 2 print T, E_av / float(N), cv