From 199b129c08242be6a2726aae3c9918ca2f2484f7 Mon Sep 17 00:00:00 2001
From: Jaron Kent-Dobias <jaron@kent-dobias.com>
Date: Fri, 15 Jan 2021 16:29:59 +0100
Subject: More changes.

---
 dynamics.hpp | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

(limited to 'dynamics.hpp')

diff --git a/dynamics.hpp b/dynamics.hpp
index 85eef71..b373659 100644
--- a/dynamics.hpp
+++ b/dynamics.hpp
@@ -92,26 +92,26 @@ Vector<Scalar> randomVector(unsigned N, Distribution d, Generator& r) {
 }
 
 template <class Scalar, int p, class Distribution, class Generator>
-std::tuple<double, Vector<Scalar>> langevin(const Tensor<Scalar, p>& J, const Vector<Scalar>& z0, double T, double γ, unsigned N, Distribution d, Generator& r) {
+std::tuple<double, Vector<Scalar>> metropolis(const Tensor<Scalar, p>& J, const Vector<Scalar>& z0,
+    std::function<double(const Tensor<Scalar, p>&, const Vector<Scalar>&)>& energy,
+    double T, double γ, unsigned N, Distribution d, Generator& r) {
   Vector<Scalar> z = z0;
 
-  double W;
-  std::tie(W, std::ignore) = WdW(J, z);
+  double E = energy(J, z);
 
   std::uniform_real_distribution<double> D(0, 1);
 
   for (unsigned i = 0; i < N; i++) {
-    Vector<Scalar> zNewTmp = z + randomVector<Scalar>(z.size(), d, r);
+    Vector<Scalar> zNewTmp = z + γ * randomVector<Scalar>(z.size(), d, r);
     Vector<Scalar> zNew = normalize(zNewTmp);
 
-    double WNew;
-    std::tie(WNew, std::ignore) = WdW(J, zNew);
+    double ENew = energy(J, zNew);
 
-    if (exp((W - WNew) / T) > D(r)) {
+    if (E - ENew > T * log(D(r))) {
       z = zNew;
-      W = WNew;
+      E = ENew;
     }
   }
 
-  return {W, z};
+  return {E, z};
 }
-- 
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