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Diffstat (limited to 'examples/clock.cpp')
-rw-r--r-- | examples/clock.cpp | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/examples/clock.cpp b/examples/clock.cpp new file mode 100644 index 0000000..4b0ffb8 --- /dev/null +++ b/examples/clock.cpp @@ -0,0 +1,98 @@ + +#include <getopt.h> +#include <iostream> +#include <chrono> + +#include "simple_measurement.hpp" + +#include <wolff/models/potts.hpp> +#include <wolff/models/dihedral.hpp> +#include <wolff/finite_states.hpp> + +#include <wolff.hpp> + +using namespace wolff; + +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; + vector_t<2, double> H; + H.fill(0.0); + q_t 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 = (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[Hi] = atof(optarg); + Hi++; + break; + default: + exit(EXIT_FAILURE); + } + } + + // define the spin-spin coupling + std::function <double(const potts_t<WOLFF_POTTSQ>&, const potts_t<WOLFF_POTTSQ>&)> Z = [] (const potts_t<WOLFF_POTTSQ>& s1, const potts_t<WOLFF_POTTSQ>& s2) -> double { + return cos(2 * M_PI * (double)(s1.x + WOLFF_POTTSQ - s2.x) / (double)WOLFF_POTTSQ); + }; + + // define the spin-field coupling + std::function <double(const potts_t<WOLFF_POTTSQ>&)> B = [=] (const potts_t<WOLFF_POTTSQ>& s) -> double { + return H[0] * cos(2 * M_PI * (double)s.x / (double)WOLFF_POTTSQ) + H[1] * sin(2 * M_PI * (double)s.x / (double)WOLFF_POTTSQ); + }; + + // initialize the lattice + graph G(D, L); + + // initialize the system + system<dihedral_t<WOLFF_POTTSQ>, potts_t<WOLFF_POTTSQ>> S(G, 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 <dihedral_t<WOLFF_POTTSQ>(std::mt19937&, const system<dihedral_t<WOLFF_POTTSQ>, potts_t<WOLFF_POTTSQ>>&, v_t)> gen_r = [] (std::mt19937& r, const system<dihedral_t<WOLFF_POTTSQ>, potts_t<WOLFF_POTTSQ>>& S, v_t i0) -> dihedral_t<WOLFF_POTTSQ> { + dihedral_t<WOLFF_POTTSQ> rot; + rot.is_reflection = true; + std::uniform_int_distribution<q_t> dist(0, WOLFF_POTTSQ - 2); + q_t x = dist(r); + rot.x = (2 * S.s[i0].x + x + 1) % WOLFF_POTTSQ; + + return rot; + }; + + // initailze the measurement object + simple_measurement A(S); + + // 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; +} + |