1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
|
#pragma once
#include <gsl/gsl_randist.h>
#include <gsl/gsl_rng.h>
#include <cmath>
#include <vector>
#include <stack>
#include "types.h"
#include "state.h"
#include "graph.h"
template <class R_t, class X_t>
void flip_cluster(state_t<R_t, X_t>& s, v_t v0, const R_t& r, gsl_rng *rand) {
v_t nv = 0;
std::stack<v_t> stack;
stack.push(v0);
std::vector<bool> marks(s.g.nv, false);
while (!stack.empty()) {
v_t v = stack.top();
stack.pop();
if (!marks[v]) { // don't reprocess anyone we've already visited!
X_t si_old, si_new;
R_t R_old, R_new;
R_old = s.R;
marks[v] = true;
bool v_is_ghost = (v == s.nv); // ghost site has the last index
if (v_is_ghost) {
R_new = r.act(R_old); // if we are, then we're moving the transformation
} else {
si_old = s.spins[v];
si_new = r.act(si_old); // otherwise, we're moving the spin at our site
}
for (const v_t &vn : s.g.v_adj[v]) {
X_t sj;
bool vn_is_ghost = (vn == s.nv); // any of our neighbors could be the ghost
if (!vn_is_ghost) {
sj = s.spins[vn];
}
double prob;
if (v_is_ghost || vn_is_ghost) { // if this is a ghost-involved bond...
X_t rs_old, rs_new;
v_t non_ghost;
if (vn_is_ghost) {
rs_old = R_old.act_inverse(si_old);
rs_new = R_old.act_inverse(si_new);
non_ghost = v;
} else {
rs_old = R_old.act_inverse(sj);
rs_new = R_new.act_inverse(sj);
non_ghost = vn;
}
double dE = s.H(rs_old) - s.H(rs_new);
#ifdef FINITE_STATES
prob = H_probs[state_to_ind(rs_old)][state_to_ind(rs_new)];
#else
prob = 1.0 - exp(-dE / s.T);
#endif
s.M -= rs_old;
s.M += rs_new;
s.E += dE;
for (D_t i = 0; i < s.D; i++) {
L_t x = (non_ghost / (v_t)pow(s.L, s.D - i - 1)) % s.L;
s.ReF[i] -= rs_old * s.precomputed_cos[x];
s.ReF[i] += rs_new * s.precomputed_cos[x];
s.ImF[i] -= rs_old * s.precomputed_sin[x];
s.ImF[i] += rs_new * s.precomputed_sin[x];
}
} else { // otherwise, we're at a perfectly normal bond!
double dE = s.J(si_old, sj) - s.J(si_new, sj);
#ifdef FINITE_STATES
prob = J_probs[state_to_ind(si_old)][state_to_ind(si_new)][state_to_ind(sj)];
#else
prob = 1.0 - exp(-dE / s.T);
#endif
s.E += dE;
}
if (gsl_rng_uniform(rand) < prob) {
stack.push(vn); // push the neighboring vertex to the stack
}
}
if (v_is_ghost) {
s.R = R_new;
} else {
s.spins[v] = si_new;
nv++;
}
}
}
s.last_cluster_size = nv;
}
|
