1 files changed, 138 insertions, 0 deletions
diff --git a/src/wolff_potts.cpp b/src/wolff_potts.cpp
new file mode 100644
index 0000000..9d22ea4
--- /dev/null
+++ b/src/wolff_potts.cpp
@@ -0,0 +1,138 @@
+
+#include <getopt.h>
+#include <GL/glut.h>
+
+// include your group and spin space
+#include <symmetric.h>
+#include <potts.h>
+
+// include wolff.h
+#include <wolff.h>
+
+int main(int argc, char *argv[]) {
+
+  count_t N = (count_t)1e7;
+
+  D_t D = 2;
+  L_t L = 128;
+  double T = 2.26918531421;
+  double H = 0.0;
+
+  bool silent = false;
+  bool draw = false;
+
+  int opt;
+
+  while ((opt = getopt(argc, argv, "N:D:L:T:H:sd")) != -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
+      H = atof(optarg);
+      break;
+    case 's': // don't print anything during simulation. speeds up slightly
+      silent = true;
+      break;
+    case 'd':
+      draw = true;
+      break;
+    default:
+      exit(EXIT_FAILURE);
+    }
+  }
+
+  // initialize random number generator
+  gsl_rng *r = gsl_rng_alloc(gsl_rng_mt19937);
+  gsl_rng_set(r, rand_seed());
+
+  // define spin-spin coupling
+  std::function <double(potts_t, ising_t)> Z = [] (ising_t s1, ising_t s2) -> double {
+    if (s1.x == s2.x) {
+      return 1.0;
+    } else {
+      return -1.0;
+    }
+  };
+
+  // define spin-field coupling
+  std::function <double(ising_t)> B = [=] (ising_t s) -> double {
+    if (s.x) {
+      return -H;
+    } else {
+      return H;
+    }
+  };
+
+  // initialize state object
+  state_t <z2_t, ising_t> s(D, L, T, Z, B);
+
+  // define function that generates self-inverse rotations
+  std::function <z2_t(gsl_rng *, const state_t <z2_t, ising_t> *)> gen_R = [] (gsl_rng *, const state_t <z2_t, ising_t> *) -> z2_t {
+    z2_t rot;
+    rot.x = true;
+    return rot;
+  };
+
+  // define function that updates any number of measurements
+  std::function <void(const state_t <z2_t, ising_t> *)> measurement;
+
+  double average_M = 0;
+  if (!draw) {
+    // a very simple example: measure the average magnetization
+    measurement = [&] (const state_t <z2_t, ising_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
+
+    // initialize glut
+    glutInit(&argc, argv);
+    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
+    glutInitWindowSize(L,L);
+    glutCreateWindow("null");
+    glClearColor(0.0,0.0,0.0,0.0);
+    glMatrixMode(GL_PROJECTION);
+    glLoadIdentity();
+    gluOrtho2D(0.0, L, 0.0, L);
+
+    measurement = [&] (const state_t <z2_t, ising_t> *s) {
+      average_M += (double)s->M / (double)N / (double)s->nv;
+      glClear(GL_COLOR_BUFFER_BIT);
+      for (v_t i = 0; i < pow(L, 2); i++) {
+        if (s->spins[i].x == s->R.x) {
+          glColor3f(0.0, 0.0, 0.0);
+        } else {
+          glColor3f(1.0, 1.0, 1.0);
+        }
+        glRecti(i / L, i % L, (i / L) + 1, (i % L) + 1);
+      }
+      glFlush();
+    };
+  }
+
+  // run wolff for N cluster flips
+  wolff(N, &s, gen_R, measurement, r, silent);
+
+  // tell us what we found!
+  printf("%" PRIcount " Ising runs completed. D = %" PRID ", L = %" PRIL ", T = %g, H = %g, <M> = %g\n", N, D, L, T, H, average_M);
+
+  // free the random number generator
+  gsl_rng_free(r);
+
+  if (draw) {
+  }
+
+  return 0;
+
+}
+