1 files changed, 112 insertions, 0 deletions
diff --git a/examples/continuous_gaussian.cpp b/examples/continuous_gaussian.cpp
new file mode 100644
index 0000000..ef08247
--- /dev/null
+++ b/examples/continuous_gaussian.cpp
@@ -0,0 +1,112 @@
+
+#include <getopt.h>
+#include <iostream>
+#include <chrono>
+
+#include "simple_measurement.hpp"
+
+#include <wolff/models/height.hpp>
+#include <wolff/models/dihedral_inf.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 = 0.8;
+  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 height_t<double>&, const height_t<double>&)> Z = [] (const height_t<double>& s1, const height_t<double>& s2) -> double {
+    return - pow(s1.x - s2.x, 2);
+  };
+
+  // define the spin-field coupling
+  std::function <double(const height_t<double>&)> B = [&] (const height_t<double>& s) -> double {
+    return - H * pow(s.x, 2);
+  };
+
+  // initialize the lattice
+  graph G(D, L);
+
+  // initialize the system
+  system<dihedral_inf_t<double>, height_t<double>> S(G, T, Z, B);
+
+  bool odd_run = false;
+
+  std::function <dihedral_inf_t<double>(std::mt19937&, const system<dihedral_inf_t<double>, height_t<double>>&, v_t)> gen_R_IH = [&](std::mt19937& r, const system<dihedral_inf_t<double>, height_t<double>>& S, v_t i0) -> dihedral_inf_t<double> {
+    dihedral_inf_t<double> rot;
+    rot.is_reflection = true;
+
+    if (odd_run) {
+      std::uniform_int_distribution<v_t> dist(0, S.nv - 2);
+      v_t j = i0;
+
+      //while (S.s[j].x == S.s[i0].x) {
+        v_t tmp = dist(r);
+
+        if (tmp < i0) {
+          j = tmp;
+        } else {
+          j = tmp + 1;
+        }
+      //}
+
+      rot.x = 2 * S.s[j].x;
+    } else {
+      std::normal_distribution<double> dist(0.0,1.0);
+      rot.x = 2 * S.s[i0].x + dist(r);
+    }
+
+    odd_run = !odd_run;
+
+    return rot;
+  };
+
+  // initailze the measurement object
+  simple_measurement A(S);
+
+  // initialize the random number generator
+  auto seed = std::chrono::high_resolution_clock::now().time_since_epoch().count();
+  std::mt19937 rng{seed};
+
+  // run wolff N times
+  S.run_wolff(N, gen_R_IH, 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;
+}
+