1 files changed, 155 insertions, 0 deletions
diff --git a/examples/src/models/potts/wolff_clock.cpp b/examples/src/models/potts/wolff_clock.cpp
new file mode 100644
index 0000000..020415d
--- /dev/null
+++ b/examples/src/models/potts/wolff_clock.cpp
@@ -0,0 +1,155 @@
+
+#include <getopt.h>
+
+#ifdef HAVE_GLUT
+#include <GL/glut.h>
+#endif
+
+// include your group and spin space
+#include "dihedral.hpp"
+#include "potts.hpp"
+#include <colors.h>
+
+// hack to speed things up considerably
+#define N_STATES POTTSQ
+#include <wolff/finite_states.hpp>
+
+#include <randutils/randutils.hpp>
+
+// include wolff.hpp
+#include <wolff.hpp>
+
+typedef state_t <dihedral_t<POTTSQ>, potts_t<POTTSQ>> sim_t;
+
+int main(int argc, char *argv[]) {
+
+  count_t N = (count_t)1e4;
+
+  D_t D = 2;
+  L_t L = 128;
+  double T = 2.26918531421;
+  double *H_vec = (double *)calloc(MAX_Q, sizeof(double));
+
+  bool silent = false;
+  bool draw = false;
+  unsigned int window_size = 512;
+
+  int opt;
+  q_t H_ind = 0;
+
+  while ((opt = getopt(argc, argv, "N:D:L:T:H:sdw:")) != -1) {
+    switch (opt) {
+    case 'N': // number of steps
+      N = (count_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. nth call couples to state n
+      H_vec[H_ind] = atof(optarg);
+      H_ind++;
+      break;
+    case 's': // don't print anything during simulation. speeds up slightly
+      silent = true;
+      break;
+    case 'd':
+#ifdef HAVE_GLUT
+      draw = true;
+      break;
+#else
+      printf("You didn't compile this with the glut library installed!\n");
+      exit(EXIT_FAILURE);
+#endif
+    case 'w':
+      window_size = atoi(optarg);
+      break;
+    default:
+      exit(EXIT_FAILURE);
+    }
+  }
+
+  // initialize random number generator
+  randutils::auto_seed_128 seeds;
+  std::mt19937 rng{seeds};
+
+  // define spin-spin coupling
+  std::function <double(const potts_t<POTTSQ>&, const potts_t<POTTSQ>&)> Z = [] (const potts_t<POTTSQ>& s1, const potts_t<POTTSQ>& s2) -> double {
+    return cos(2 * M_PI * (double)(s1.x + POTTSQ - s2.x) / (double)POTTSQ);
+  };
+
+  // define spin-field coupling
+  std::function <double(const potts_t<POTTSQ>&)> B = [=] (const potts_t<POTTSQ>& s) -> double {
+    return H_vec[s.x];
+  };
+
+  // initialize state object
+  state_t <dihedral_t<POTTSQ>, potts_t<POTTSQ>> s(D, L, T, Z, B);
+
+  // define function that generates self-inverse rotations
+  std::function <dihedral_t<POTTSQ>(std::mt19937&, potts_t<POTTSQ>)> gen_R = [] (std::mt19937& r, potts_t<POTTSQ> v) -> dihedral_t<POTTSQ> {
+    dihedral_t<POTTSQ> rot;
+    rot.is_reflection = true;
+    std::uniform_int_distribution<q_t> dist(0, POTTSQ - 1);
+    q_t x = dist(r);
+    rot.x = (2 * v.x + x + 1) % POTTSQ;
+
+    return rot;
+  };
+
+  // define function that updates any number of measurements
+  std::function <void(const sim_t&)> measurement;
+
+  double average_M = 0;
+  if (!draw) {
+    // a very simple example: measure the average magnetization
+    measurement = [&] (const sim_t& s) {
+      average_M += (double)s.M[0] / (double)N / (double)s.nv;
+    };
+  } else {
+    // a more complex example: measure the average magnetization, and draw the spin configuration to the screen
+
+#ifdef HAVE_GLUT
+    // initialize glut
+    glutInit(&argc, argv);
+    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
+    glutInitWindowSize(window_size, window_size);
+    glutCreateWindow("wolff");
+    glClearColor(0.0,0.0,0.0,0.0);
+    glMatrixMode(GL_PROJECTION);
+    glLoadIdentity();
+    gluOrtho2D(0.0, L, 0.0, L);
+
+    measurement = [&] (const sim_t& s) {
+      average_M += (double)s.M[0] / (double)N / (double)s.nv;
+      glClear(GL_COLOR_BUFFER_BIT);
+      for (v_t i = 0; i < pow(L, 2); i++) {
+        potts_t<POTTSQ> tmp_s = s.R.act_inverse(s.spins[i]);
+        glColor3f(hue_to_R(tmp_s.x * 2 * M_PI / POTTSQ), hue_to_G(tmp_s.x * 2 * M_PI / POTTSQ), hue_to_B(tmp_s.x * 2 * M_PI / POTTSQ));
+        glRecti(i / L, i % L, (i / L) + 1, (i % L) + 1);
+      }
+      glFlush();
+    };
+#endif
+  }
+
+  // run wolff for N cluster flips
+  wolff(N, s, gen_R, measurement, rng, silent);
+
+  // tell us what we found!
+  printf("%" PRIcount " %d-Potts runs completed. D = %" PRID ", L = %" PRIL ", T = %g, H = %g, <M> = %g\n", N, POTTSQ, D, L, T, H_vec[0], average_M);
+
+  // free the random number generator
+
+  if (draw) {
+  }
+
+  return 0;
+
+}
+