1 files changed, 164 insertions, 0 deletions
diff --git a/examples/src/models/roughening/wolff_dgm.cpp b/examples/src/models/roughening/wolff_dgm.cpp
new file mode 100644
index 0000000..8395382
--- /dev/null
+++ b/examples/src/models/roughening/wolff_dgm.cpp
@@ -0,0 +1,164 @@
+
+#include <getopt.h>
+
+#ifdef HAVE_GLUT
+#include <GL/glut.h>
+#endif
+
+// include your group and spin space
+#include "dihedral_inf.hpp"
+#include "height.hpp"
+
+#include <randutils/randutils.hpp>
+
+// include wolff.h
+#include <wolff.hpp>
+
+typedef state_t <dihedral_inf_t<int64_t>, height_t<int64_t>> 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 = 0;
+
+  bool silent = false;
+  bool draw = false;
+  unsigned int window_size = 512;
+  uint64_t epsilon = 1;
+
+  int opt;
+
+  while ((opt = getopt(argc, argv, "N:D:L:T:H:sdw:e:")) != -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 = atof(optarg);
+      break;
+    case 'e': // external field. nth call couples to state n
+      epsilon = atof(optarg);
+      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 height_t<int64_t>&, const height_t<int64_t>&)> Z = [] (const height_t<int64_t>& h1, const height_t<int64_t>& h2) -> double {
+    return -pow(h1.x - h2.x, 2);
+  };
+
+  // define spin-field coupling
+  std::function <double(const height_t<int64_t> &)> B = [=] (const height_t<int64_t>& h) -> double {
+    return -H * pow(h.x, 2);;
+  };
+
+  // initialize state object
+  sim_t s(D, L, T, Z, B);
+
+  // define function that generates self-inverse rotations
+  std::function <dihedral_inf_t<int64_t>(std::mt19937&, height_t<int64_t>)> gen_R = [=] (std::mt19937& r, height_t<int64_t> h) -> dihedral_inf_t<int64_t> {
+    dihedral_inf_t<int64_t> rot;
+    rot.is_reflection = true;
+
+    std::uniform_int_distribution<int64_t> dist(-epsilon,epsilon);
+
+    rot.x = 2 * h.x + dist(r);
+
+    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 / (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 / (double)N / (double)s.nv;
+      glClear(GL_COLOR_BUFFER_BIT);
+      int64_t max_h = INT64_MIN;
+      int64_t min_h = INT64_MAX;
+      for (v_t i = 0; i < pow(L, 2); i++) {
+        int64_t cur_h = (s.R.act_inverse(s.spins[i])).x;
+        if (cur_h < min_h) {
+          min_h = cur_h;
+        }
+        if (cur_h > max_h) {
+          max_h = cur_h;
+        }
+      }
+
+      for (v_t i = 0; i < pow(L, 2); i++) {
+        int64_t cur_h = (s.R.act_inverse(s.spins[i])).x;
+        double mag = ((double)(cur_h - min_h)) / ((double)(max_h - min_h));
+        glColor3f(mag, mag, mag);
+        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 " DGM runs completed. D = %" PRID ", L = %" PRIL ", T = %g, H = %g, <M> = %g\n", N, D, L, T, H, average_M);
+
+  if (draw) {
+  }
+
+  return 0;
+
+}
+