From 9c2a77d4cc668a9d5fc25d7bd15ad8a34ac90d34 Mon Sep 17 00:00:00 2001
From: Jaron Kent-Dobias <jaron@kent-dobias.com>
Date: Mon, 10 Oct 2022 18:01:31 +0200
Subject: Changed weight structure to a stack.

---
 uniform.cpp | 37 ++++++++++++++++++-------------------
 1 file changed, 18 insertions(+), 19 deletions(-)

(limited to 'uniform.cpp')

diff --git a/uniform.cpp b/uniform.cpp
index c7d6367..53fd60b 100644
--- a/uniform.cpp
+++ b/uniform.cpp
@@ -1,7 +1,6 @@
 #include <functional>
 #include <iostream>
-#include <list>
-#include <ranges>
+#include <stack>
 
 #include "randutils/randutils.hpp"
 #include "pcg-cpp/include/pcg_random.hpp"
@@ -10,7 +9,7 @@ using Rng = randutils::random_generator<pcg32>;
 using Real = long double;
 
 typedef struct Edge {
-  std::list<Real> weights;
+  std::stack<Real> weights;
   Real probability = 0;
 } Edge;
 
@@ -41,27 +40,27 @@ public:
   void computeWeights() {
     for (std::vector<Face>& faces : lattices) {
       for (Face& f : faces) {
-        Real w = f[0].get().weights.back();
-        Real x = f[1].get().weights.back();
-        Real y = f[2].get().weights.back();
-        Real z = f[3].get().weights.back();
+        Real w = f[0].get().weights.top();
+        Real x = f[1].get().weights.top();
+        Real y = f[2].get().weights.top();
+        Real z = f[3].get().weights.top();
 
         Real cellFactor = w * z + x * y;
 
-        f[0].get().weights.push_back(z / cellFactor);
-        f[1].get().weights.push_back(y / cellFactor);
-        f[2].get().weights.push_back(x / cellFactor);
-        f[3].get().weights.push_back(w / cellFactor);
+        f[0].get().weights.push(z / cellFactor);
+        f[1].get().weights.push(y / cellFactor);
+        f[2].get().weights.push(x / cellFactor);
+        f[3].get().weights.push(w / cellFactor);
       }
     }
 
     // This process computes one extra weight per edge.
     for (Edge& e : edges) {
-      e.weights.pop_back();
+      e.weights.pop();
     }
   }
 
-  void computeProbabilities() {
+  void computeProbabilities() { // destroys *all* weights
     for (auto it = lattices.rbegin(); it != lattices.rend(); it++) {
       for (Face& f : *it) {
         Real p = f[0].get().probability;
@@ -69,10 +68,10 @@ public:
         Real r = f[2].get().probability;
         Real s = f[3].get().probability;
 
-        Real w = f[0].get().weights.back();
-        Real x = f[1].get().weights.back();
-        Real y = f[2].get().weights.back();
-        Real z = f[3].get().weights.back();
+        Real w = f[0].get().weights.top();
+        Real x = f[1].get().weights.top();
+        Real y = f[2].get().weights.top();
+        Real z = f[3].get().weights.top();
 
         Real cellFactor = w * z + x * y;
         Real deficit = 1 - p - q - r - s;
@@ -83,7 +82,7 @@ public:
         f[3].get().probability = p + deficit * w * z / cellFactor;
 
         for (Edge& e : f) {
-          e.weights.pop_back();
+          e.weights.pop();
         }
       }
     }
@@ -120,7 +119,7 @@ int main(int argc, char* argv[]) {
 
   for (unsigned i = 0; i < m; i++) {
     for (Edge& e : a.edges) {
-      e.weights = {exp(- r.variate<Real, std::exponential_distribution>(1) / T)};
+      e.weights.push(exp(- r.variate<Real, std::exponential_distribution>(1) / T));
       e.probability = 0;
     }
     a.computeWeights();
-- 
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