From 5020a6cf9585d7066553146920253cf856b7384a Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Sun, 12 Jul 2026 17:21:57 +0000
Subject: [PATCH] Refactor LINQ .ToDictionary() into Dictionary copy
 constructor for Context copies

Replaces LINQ's `.ToDictionary(pair => pair.Key, pair => pair.Value, Comparer)` with the native `Dictionary` copy constructor `new Dictionary<string, double>(source, Comparer)`. This removes enumerable closures and delegate overhead in hot paths during `TemporalNetworkSimulationEngine.cs`.
---
 .jules/bolt.md                                              | 3 +++
 .../Services/TemporalNetworkSimulationEngine.cs             | 6 +++---
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/.jules/bolt.md b/.jules/bolt.md
index ad98065..31021c5 100644
--- a/.jules/bolt.md
+++ b/.jules/bolt.md
@@ -88,3 +88,6 @@
 ## 2026-06-15 - Optimize Multiple ToDictionary Allocations inside Workspace UI
 **Learning:** In C#, executing multiple LINQ `.ToDictionary()` allocations on the same source collection (like building 9 different actor metrics dictionaries from `SimulationActors`) inside UI metric generation code allocates massive amounts of redundant enumerators, delegates, and intermediate dictionary structures on the UI thread, causing unnecessary memory allocation and garbage collection pauses.
 **Action:** Replace multiple `.ToDictionary()` allocations on identical source collections with a single manual `foreach` loop that populates pre-allocated dictionaries simultaneously. This transforms an O(K*N) allocation into a tight O(N) loop and completely avoids LINQ overhead.
+## 2024-05-31 - [Optimize ToDictionary with manual Dictionary copy constructor]
+**Learning:** In C#, replacing `context.Supply.ToDictionary(pair => pair.Key, pair => pair.Value, Comparer)` with the native dictionary copy constructor `new Dictionary<string, double>(context.Supply, Comparer)` avoids multiple LINQ enumerator allocations and delegate creations for the hot `ToRoutingContext` path inside `TemporalNetworkSimulationEngine`.
+**Action:** Replace direct `.ToDictionary` invocations with `new Dictionary(source, Comparer)` when copying dictionaries where the source implements `IDictionary<TKey, TValue>`.
diff --git a/src/MedWNetworkSim.App/Services/TemporalNetworkSimulationEngine.cs b/src/MedWNetworkSim.App/Services/TemporalNetworkSimulationEngine.cs
index fb2e2ad..5ea9999 100644
--- a/src/MedWNetworkSim.App/Services/TemporalNetworkSimulationEngine.cs
+++ b/src/MedWNetworkSim.App/Services/TemporalNetworkSimulationEngine.cs
@@ -1072,9 +1072,9 @@ private static RoutingTrafficContext ToRoutingContext(TemporalTrafficContext con
             Seed = context.Seed,
             NodesById = context.NodesById,
             ProfilesByNodeId = context.ProfilesByNodeId,
-            Supply = context.Supply.ToDictionary(pair => pair.Key, pair => pair.Value, Comparer),
-            SupplyUnitCosts = context.SupplyUnitCosts.ToDictionary(pair => pair.Key, pair => pair.Value, Comparer),
-            Demand = context.Demand.ToDictionary(pair => pair.Key, pair => pair.Value, Comparer),
+            Supply = new Dictionary<string, double>(context.Supply, Comparer),
+            SupplyUnitCosts = new Dictionary<string, double>(context.SupplyUnitCosts, Comparer),
+            Demand = new Dictionary<string, double>(context.Demand, Comparer),
             MeetingDemandEligibleNodeIds = context.MeetingDemandEligibleNodeIds
         };
     }