diff options
Diffstat (limited to 'examples/ising.cpp')
-rw-r--r-- | examples/ising.cpp | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/examples/ising.cpp b/examples/ising.cpp new file mode 100644 index 0000000..ffcb7e4 --- /dev/null +++ b/examples/ising.cpp @@ -0,0 +1,82 @@ + +#include <getopt.h> +#include <iostream> +#include <chrono> + +#include "simple_measurement.hpp" + +#include <wolff/models/ising.hpp> +#include <wolff/finite_states.hpp> +#include <wolff.hpp> + +int main(int argc, char *argv[]) { + + // set defaults + N_t N = (N_t)1e4; + D_t D = 2; + L_t L = 128; + double T = 2.26918531421; + double H = 0.0; + + 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 = (N_t)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 = atof(optarg); + break; + default: + exit(EXIT_FAILURE); + } + } + + // define the spin-spin coupling + std::function <double(const ising_t&, const ising_t&)> Z = [] (const ising_t& s1, const ising_t& s2) -> double { + return (double)(s1 * s2); + }; + + // define the spin-field coupling + std::function <double(const ising_t&)> B = [=] (const ising_t& s) -> double { + return H * s; + }; + + // initialize the system + wolff_system<ising_t, ising_t> S(D, L, T, Z, B); + + // initialize the random number generator + auto seed = std::chrono::high_resolution_clock::now().time_since_epoch().count(); + std::mt19937 rng{seed}; + + // define function that generates self-inverse rotations + std::function <ising_t(std::mt19937&, const ising_t&)> gen_R = [] (std::mt19937&, const ising_t& s) -> ising_t { + return ising_t(true); + }; + + // initailze the measurement object + simple_measurement A(S); + + // run wolff N times + wolff<ising_t, ising_t>(N, S, 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; +} + |