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
|
#include <getopt.h>
#include <iostream>
#include <chrono>
#include <wolff_models/vector.hpp>
#include <wolff_models/orthogonal.hpp>
#include "simple_measurement.hpp"
int main(int argc, char *argv[]) {
// set defaults
unsigned N = (unsigned)1e4;
unsigned D = 2;
unsigned L = 128;
double T = 0.8;
vector_t<WOLFF_N, double> H;
H.fill(0.0);
unsigned Hi = 0;
int opt;
// take command line arguments
while ((opt = getopt(argc, argv, "N:D:L:T:H:")) != -1) {
switch (opt) {
case 'N': // number of steps
N = (unsigned)atof(optarg);
break;
case 'D': // dimension
D = atoi(optarg);
break;
case 'L': // linear size
L = atoi(optarg);
break;
case 'T': // temperature
T = atof(optarg);
break;
case 'H': // external field
H[Hi] = atof(optarg);
Hi++;
break;
default:
exit(EXIT_FAILURE);
}
}
// define the spin-spin coupling
std::function <double(const vector_t<WOLFF_N, double>&, const vector_t<WOLFF_N, double>&)> Z = [] (const vector_t<WOLFF_N, double>& s1, const vector_t<WOLFF_N, double>& s2) -> double {
return s1 * s2;
};
// define the spin-field coupling
std::function <double(const vector_t<WOLFF_N, double>&)> B = [&] (const vector_t<WOLFF_N, double>& s) -> double {
return H * s;
};
// initialize the lattice
graph<> G(D, L);
// initialize the system
wolff::system<orthogonal_t<WOLFF_N, double>, vector_t<WOLFF_N, double>> S(G, T, Z, B);
std::function <orthogonal_t<WOLFF_N, double>(std::mt19937&, const wolff::system<orthogonal_t<WOLFF_N, double>, vector_t<WOLFF_N, double>, graph<>>&, const graph<>::vertex)> gen_R = generate_rotation_uniform<WOLFF_N, graph<>>;
// initailze the measurement object
simple_measurement A(S);
// initialize the random number generator
auto seed = std::chrono::high_resolution_clock::now().time_since_epoch().count();
std::mt19937 rng(seed);
// run wolff N times
S.run_wolff(N, gen_R, A, rng);
// print the result of our measurements
std::cout << "Wolff complete!\nThe average energy per site was " << A.avgE() / S.nv
<< ".\nThe average magnetization per site was " << A.avgM() / S.nv
<< ".\nThe average cluster size per site was " << A.avgC() / S.nv << ".\n";
// exit
return 0;
}
|
