Enumerate ising.py
From Werner KRAUTH
(Difference between revisions)
| Revision as of 21:55, 22 September 2015 Werner (Talk | contribs) ← Previous diff |
Current revision Werner (Talk | contribs) |
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| - | This page presents the program enumerate_ising.py, an enumeration algorithm for the Ising model using the Gray code. | + | This page presents the Python3 program enumerate_ising.py, an enumeration algorithm for the Ising model using the Gray code, on the two-dimensional L x L lattice with periodic boundary conditions. As it stands, the program is only really suited for L=2 and L=4. As Python is a bit slow, it will take a few hours to terminate for L=6. |
| __FORCETOC__ | __FORCETOC__ | ||
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| E += 2 * h * S[k - 1] | E += 2 * h * S[k - 1] | ||
| S[k - 1] *= -1 | S[k - 1] *= -1 | ||
| - | print S, E | + | print(S, E) |
| =Version= | =Version= | ||
| See history for version information. | See history for version information. | ||
| - | [[Category:Python]] [[Category:Honnef_2015]] [[Category:MOOC_SMAC]] | + | [[Category:Python]] [[Category:Oxford_2024]] [[Category:MOOC_SMAC]] |
Current revision
This page presents the Python3 program enumerate_ising.py, an enumeration algorithm for the Ising model using the Gray code, on the two-dimensional L x L lattice with periodic boundary conditions. As it stands, the program is only really suited for L=2 and L=4. As Python is a bit slow, it will take a few hours to terminate for L=6.
Contents |
[edit]
Description
[edit]
Program
def gray_flip(t, N):
k = t[0]
if k > N: return t, k
t[k - 1] = t[k]
t[k] = k + 1
if k != 1: t[0] = 1
return t, k
L = 4
N = L * L
nbr = {i : ((i // L) * L + (i + 1) % L, (i + L) % N,
(i // L) * L + (i - 1) % L, (i - L) % N)
for i in range(N)}
S = [-1] * N
E = -2 * N
print S, E
tau = range(1, N + 2)
for i in range(1, 2 ** N):
tau, k = gray_flip(tau, N)
h = sum(S[n] for n in nbr[k - 1])
E += 2 * h * S[k - 1]
S[k - 1] *= -1
print(S, E)
[edit]
Version
See history for version information.
