1 files changed, 151 insertions, 0 deletions
diff --git a/kauzmann.cpp b/kauzmann.cpp
new file mode 100644
index 0000000..fe0c242
--- /dev/null
+++ b/kauzmann.cpp
@@ -0,0 +1,151 @@
+
+#include "hadamard_mcmc.hpp"
+#include "quantity.hpp"
+#include "matrices.hpp"
+
+#include <chrono>
+#include <fstream>
+#include <iostream>
+
+std::string getFilename(unsigned n, double β, double θ₀) {
+  return "kauzmann_" + std::to_string(n) + "_" + std::to_string(β) + "_" + std::to_string(θ₀) + ".dat";
+}
+
+class MeasureEnergy : public Measurement {
+public:
+  Quantity Eavg;
+
+  MeasureEnergy(unsigned lag) : Eavg(lag) {}
+
+  void after_sweep(double, double E, const Orthogonal& M) override {
+    Eavg.add(E);
+  }
+};
+
+int main(int argc, char* argv[]) {
+  // model parameters
+  unsigned n = 2; // matrix size over four
+
+  // temperatures to simulate
+  double β₀ = 1; // starting temperature
+  double Δβ = 0.5; // step size
+  double β₁ = 50; // ending temperature
+
+  // simulation settings
+  unsigned m = 1e4; // number of tuning sweeps at each temperature
+  unsigned N = 1e3; // number of autocorrelation times to simulate
+  double ε = 0.1; // uncertainty on autocorrelation time
+  double θ₀ = 0.05; // standard deviation of step size
+
+  // measurement settings
+  unsigned l = 1e3; // lag in autocorrelation function
+
+  bool loadInitialFromFile = false;
+  std::string inFilename;
+
+  bool loadDataFromFile = false;
+
+  int opt;
+
+  while ((opt = getopt(argc, argv, "n:b:d:c:m:N:e:l:t:i:L")) != -1) {
+    switch (opt) {
+    case 'n':
+      n = atoi(optarg);
+      break;
+    case 'b':
+      β₀ = atof(optarg);
+      break;
+    case 'd':
+      Δβ = atof(optarg);
+      break;
+    case 'c':
+      β₁ = atof(optarg);
+      break;
+    case 'm':
+      m = (unsigned)atof(optarg);
+      break;
+    case 'N':
+      N = (unsigned)atof(optarg);
+      break;
+    case 'e':
+      ε = atof(optarg);
+      break;
+    case 'l':
+      l = (unsigned)atof(optarg);
+      break;
+    case 't':
+      θ₀ = atof(optarg);
+      break;
+    case 'i':
+      loadInitialFromFile = true;
+      inFilename = optarg;
+      break;
+    case 'L':
+      loadDataFromFile = true;
+      break;
+    default:
+      exit(1);
+    }
+  }
+
+  double β = β₀;
+
+  MeasureEnergy energyMeasurement(l);
+  MCMC simulation(n, β₀, energyMeasurement, θ₀);
+
+  if (loadInitialFromFile) {
+    std::ifstream inFile(inFilename);
+    inFile.ignore(std::numeric_limits<std::streamsize>::max(),'\n');
+    inFile.ignore(std::numeric_limits<std::streamsize>::max(),'\n');
+    for (unsigned i = 0; i < n; i++) {
+      for (unsigned j = 0; j < n; j++) {
+        inFile >> simulation.M(i, j);
+      }
+    }
+
+    simulation.E = simulation.M.energy();
+
+    std::cout << "Kauzmann: Imported matrix from file, energy " << simulation.E << "." << std::endl;
+  }
+
+  if (loadDataFromFile) {
+    energyMeasurement.Eavg.read(getFilename(n, β, θ₀));
+    std::cout << "Kauzmann: Imported data from file, number of steps " << energyMeasurement.Eavg.num_added() << "." << std::endl;
+  }
+
+  while (β <= β₁) {
+    std::cout << "Kauzmann: Starting simulation of " << β << "." << std::endl;
+    double rat = 0;
+    unsigned num = 0;
+    simulation.run(m, true);
+    simulation.run(l);
+    while (true) {
+      Quantity EavgBak = energyMeasurement.Eavg;
+      Orthogonal Mbak = simulation.M;
+      rat += simulation.run(m);
+      num++;
+      std::array<double, 2> τ = energyMeasurement.Eavg.τ();
+      std::cout << "Kauzmann: After " << energyMeasurement.Eavg.num_added() << " steps the autocorrelation time is " << τ[0] << " ± " << τ[1] << "." << std::endl;
+      if (τ[1] / τ[0] < ε && τ[0] * N <= energyMeasurement.Eavg.num_added()) {
+        break;
+      }
+    }
+    std::cout << "Kauzmann: Finished simulation of " << β << ", " << rat / num << " acceptance ratio, writing output file." << std::endl;
+    std::string filename = getFilename(n, β, θ₀);
+    energyMeasurement.Eavg.write(filename);
+    std::ofstream outFile(filename, std::ios::app);
+    for (unsigned i = 0; i < n; i++) {
+      for (unsigned j = 0; j < n; j++) {
+        outFile << simulation.M(i, j) << " ";
+      }
+    }
+    outFile << std::endl;
+    outFile.close();
+    energyMeasurement.Eavg.reset();
+    β += Δβ;
+    simulation.β = β;
+  }
+
+  return 0;
+}
+