From 1da9ba0af64dd1ff07c9fda6226689b4e8701e43 Mon Sep 17 00:00:00 2001
From: Jaron Kent-Dobias <jaron@kent-dobias.com>
Date: Tue, 25 Feb 2020 15:23:41 -0500
Subject: Minor refactoring of sphere commands and animation class, and
 introduction of Dimers

---
 spheres.hpp | 112 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 112 insertions(+)
 create mode 100644 spheres.hpp

(limited to 'spheres.hpp')

diff --git a/spheres.hpp b/spheres.hpp
new file mode 100644
index 0000000..040313c
--- /dev/null
+++ b/spheres.hpp
@@ -0,0 +1,112 @@
+
+#include "space_wolff.hpp"
+
+template <int D>
+std::function<double(const Spin<double, D, Radius>&, const Spin<double, D, Radius>&)>
+zSpheres(double a, double k) {
+  return [a, k](const Spin<double, D, Radius>& s1, const Spin<double, D, Radius>& s2) -> double {
+    Vector<double, D> d = s1.x - s2.x;
+
+    double σ = s1.s + s2.s;
+    double δ = σ - sqrt(d.transpose() * d);
+
+    if (δ > -a * σ) {
+      return 0.5 * k * (2 * pow(a * σ, 2) - pow(δ, 2));
+    } else if (δ > -2 * a * σ) {
+      return 0.5 * k * pow(δ + 2 * a * σ, 2);
+    } else {
+      return 0;
+    }
+  };
+}
+
+template <int D, class S> std::function<double(Spin<double, D, S>)> bCenter(double H) {
+  return [H](Spin<double, D, S> s) -> double { return H * s.x.norm(); };
+}
+
+template <int D> Euclidean<double, D> flipAround(double θ, Vector<double, D>& t₀) {
+  Matrix<double, D> m;
+
+  m(0, 0) = -cos(2 * θ);
+  m(1, 1) = cos(2 * θ);
+  m(0, 1) = -2 * cos(θ) * sin(θ);
+  m(1, 0) = -2 * cos(θ) * sin(θ);
+
+  return Euclidean<double, D>(t₀ - m * t₀, m);
+}
+
+template <int D, class S> Gen<double, D, Euclidean<double, D>, S> nudgeGen(double ε) {
+  return [ε](Model<double, D, Euclidean<double, D>, S>& M,
+             Rng& rng) -> Transformation<double, D, Euclidean<double, D>, S>* {
+    double θ = rng.uniform((double)0.0, 2 * M_PI);
+
+    Spin<double, D, S>* s = rng.pick(M.s);
+    Vector<double, D> t = s->x;
+    for (unsigned j = 0; j < D; j++) {
+      t(j) += rng.variate<double, std::normal_distribution>(0.0, ε);
+    }
+
+    return new SpinFlip<double, D, Euclidean<double, D>, S>(M, flipAround(θ, t), s);
+  };
+}
+
+template <int D, class S> Gen<double, D, Euclidean<double, D>, S> swapGen(double ε) {
+  return [ε](Model<double, D, Euclidean<double, D>, S>& M,
+             Rng& rng) -> Transformation<double, D, Euclidean<double, D>, S>* {
+    Spin<double, D, S>* s1 = rng.pick(M.s);
+    Spin<double, D, S>* s2 = rng.pick(M.s);
+
+    while (s1 == s2) {
+      s2 = rng.pick(M.s);
+    }
+
+    Vector<double, D> t1 = s1->x;
+    Vector<double, D> t2 = s2->x;
+    Vector<double, D> t12 = t1 - t2;
+    Vector<double, D> t = (t1 + t2) / 2;
+
+    double θ =
+        atan2(t12(1), t12(0)) + rng.variate<double, std::normal_distribution>(0.0, ε) / t12.norm();
+
+    return new PairFlip<double, D, Euclidean<double, D>, S>(M, flipAround(θ, t), s1, s2);
+  };
+}
+
+template <int D, class S> Gen<double, D, Euclidean<double, D>, S> accrossGen(double ε) {
+  return [ε](Model<double, D, Euclidean<double, D>, S>& M,
+             Rng& rng) -> Transformation<double, D, Euclidean<double, D>, S>* {
+    Spin<double, D, S>* s1 = rng.pick(M.s);
+    Spin<double, D, S>* s2 = rng.pick(M.s);
+
+    while (s1 == s2) {
+      s2 = rng.pick(M.s);
+    }
+
+    Vector<double, D> t1 = s1->x;
+    Vector<double, D> t2 = s2->x;
+    Vector<double, D> t12 = t1 - t2;
+    Vector<double, D> t = t2;
+
+    double θ =
+        atan2(t12(1), t12(0)) + rng.variate<double, std::normal_distribution>(0.0, ε) / t12.norm();
+
+    return new SpinFlip<double, D, Euclidean<double, D>, S>(M, flipAround(θ, t), s1);
+  };
+}
+
+template <int D, class S> Gen<double, D, Euclidean<double, D>, S> centerGen(double ε) {
+  return [ε](Model<double, D, Euclidean<double, D>, S>& M,
+             Rng& rng) -> Transformation<double, D, Euclidean<double, D>, S>* {
+    double θ = rng.uniform((double)0.0, 2 * M_PI);
+
+    Vector<double, D> t = M.s0.t;
+    for (unsigned j = 0; j < D; j++) {
+      t(j) += rng.variate<double, std::normal_distribution>(0.0, ε);
+    }
+
+    Spin<double, D, S>* s = rng.pick(M.s);
+
+    return new SpinFlip<double, D, Euclidean<double, D>, S>(M, flipAround(θ, t), s);
+  };
+}
+
-- 
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