From 29f28945a5de06d88b65865e932a0a53ada0ff2f Mon Sep 17 00:00:00 2001
From: Jaron Kent-Dobias <jaron@kent-dobias.com>
Date: Tue, 5 Jan 2021 11:41:24 +0100
Subject: Some helpful comments.

---
 langevin.cpp | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/langevin.cpp b/langevin.cpp
index 119a64b..1a0e104 100644
--- a/langevin.cpp
+++ b/langevin.cpp
@@ -23,21 +23,21 @@ using Tensor = Eigen::Tensor<Scalar, PSPIN_P>;
 
 using Rng = randutils::random_generator<pcg32>;
 
-Vector initializeVector(unsigned N, Rng& r) {
+Vector initializeVector(unsigned N, double a, Rng& r) {
   Vector z(N);
-  complex_normal_distribution<> dist(0, 1, 0);
+  complex_normal_distribution<> dist(0, a, 0);
 
   for (unsigned i = 0; i < N; i++) {
     z(i) = dist(r.engine());
   }
 
-  z *= sqrt(N) / sqrt(z.dot(z));
+  z *= sqrt(N) / sqrt(z.dot(z)); // Normalize.
 
   return z;
 }
 
 std::tuple<Scalar, Vector, Matrix> hamGradHess(const Tensor& J, const Vector& z) {
-  Matrix Jz = contractDown(J, z);
+  Matrix Jz = contractDown(J, z); // Contracts J into p - 2 copies of z.
   Vector Jzz = Jz * z;
 
   double f = factorial(p);
@@ -145,7 +145,7 @@ int main(int argc, char* argv[]) {
   complex_normal_distribution<> d(0, σ, κ);
 
   Tensor J = generateCouplings<Scalar, PSPIN_P>(N, d, r.engine());
-  Vector z = initializeVector(N, r);
+  Vector z = initializeVector(N, 100, r);
 
   std::function<bool(double, unsigned)> findSaddle = [δ](double W, unsigned) {
     std::cout << W << std::endl;
@@ -161,6 +161,5 @@ int main(int argc, char* argv[]) {
 
   Vector constraint = dH - ((double)p * H / (double)N) * zm;
 
-  std::cout << std::endl << zm.dot(zm) << std::endl;
-  std::cout << constraint.cwiseAbs2().sum() << std::endl;
+  std::cout << H / (double)N << std::endl;
 }
-- 
cgit v1.2.3-70-g09d2