From f2f7a072216dfafab89851e4ff3e0b2c3eb16663 Mon Sep 17 00:00:00 2001
From: Jaron Kent-Dobias <jaron@kent-dobias.com>
Date: Wed, 17 Oct 2018 19:33:25 -0400
Subject: removed a lot of research code to simplify library and examples for
 publication

---
 examples/ising.cpp | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 82 insertions(+)
 create mode 100644 examples/ising.cpp

(limited to 'examples/ising.cpp')

diff --git a/examples/ising.cpp b/examples/ising.cpp
new file mode 100644
index 0000000..ffcb7e4
--- /dev/null
+++ b/examples/ising.cpp
@@ -0,0 +1,82 @@
+
+#include <getopt.h>
+#include <iostream>
+#include <chrono>
+
+#include "simple_measurement.hpp"
+
+#include <wolff/models/ising.hpp>
+#include <wolff/finite_states.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 = 2.26918531421;
+  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 ising_t&, const ising_t&)> Z = [] (const ising_t& s1, const ising_t& s2) -> double {
+    return (double)(s1 * s2);
+  };
+
+  // define the spin-field coupling
+  std::function <double(const ising_t&)> B = [=] (const ising_t& s) -> double {
+    return H * s;
+  };
+
+  // initialize the system
+  wolff_system<ising_t, ising_t> S(D, L, 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 <ising_t(std::mt19937&, const ising_t&)> gen_R = [] (std::mt19937&, const ising_t& s) -> ising_t {
+    return ising_t(true);
+  };
+
+  // initailze the measurement object
+  simple_measurement A(S);
+
+  // run wolff N times
+  wolff<ising_t, ising_t>(N, S, 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;
+}
+
-- 
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