From 50c52079f8a4e42698200251578ca532cf6510a9 Mon Sep 17 00:00:00 2001
From: marecabo <23156476+marecabo@users.noreply.github.com>
Date: Sat, 8 Jun 2024 13:24:55 +0200
Subject: [PATCH] Only parallelize getting activityEndTimes

---
 .../dynagent/run/DynActivityEngine.java       | 53 ++++++++++---------
 1 file changed, 27 insertions(+), 26 deletions(-)

diff --git a/contribs/dvrp/src/main/java/org/matsim/contrib/dynagent/run/DynActivityEngine.java b/contribs/dvrp/src/main/java/org/matsim/contrib/dynagent/run/DynActivityEngine.java
index cfb0958c0c8..1872d6ff35c 100644
--- a/contribs/dvrp/src/main/java/org/matsim/contrib/dynagent/run/DynActivityEngine.java
+++ b/contribs/dvrp/src/main/java/org/matsim/contrib/dynagent/run/DynActivityEngine.java
@@ -20,11 +20,13 @@
 package org.matsim.contrib.dynagent.run;
 
 import java.util.ArrayList;
+import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
-import java.util.Objects;
+import java.util.Map;
 
 import org.matsim.api.core.v01.Id;
+import org.matsim.api.core.v01.IdCollectors;
 import org.matsim.api.core.v01.network.Link;
 import org.matsim.api.core.v01.population.Person;
 import org.matsim.contrib.dynagent.DynAgent;
@@ -56,31 +58,30 @@ public void doSimStep(double time) {
 		dynAgents.addAll(newDynAgents);
 		newDynAgents.clear();
 
-		List<DynAgent> agentsToRemove = dynAgents.parallelStream()
-				.map(agent -> {
-
-					Preconditions.checkState(agent.getState() == State.ACTIVITY);
-					agent.doSimStep(time);
-					// ask agents about the current activity end time;
-					double currentEndTime = agent.getActivityEndTime();
-
-					if (currentEndTime == Double.POSITIVE_INFINITY) { // agent says: stop simulating me
-						unregisterAgentAtActivityLocation(agent);
-						internalInterface.getMobsim().getAgentCounter().decLiving();
-						return agent;
-					} else if (currentEndTime <= time) { // the agent wants to end the activity NOW
-						unregisterAgentAtActivityLocation(agent);
-						agent.endActivityAndComputeNextState(time);
-						internalInterface.arrangeNextAgentState(agent);
-						return agent;
-					}
-
-					return null;
-				})
-				.filter(Objects::nonNull)
-				.toList();
-
-		dynAgents.removeAll(agentsToRemove);
+		// computing end times is the heaviest part here and can be parallelized
+		// Todo: use forkJoinPool and respect globalThreads property
+		Map<Id<Person>, Double> activityEndTimes = dynAgents.parallelStream()
+				.collect(IdCollectors.toIdMap(Person.class, MobsimAgent::getId, MobsimAgent::getActivityEndTime));
+
+		Iterator<DynAgent> dynAgentIter = dynAgents.iterator();
+		while (dynAgentIter.hasNext()) {
+			DynAgent agent = dynAgentIter.next();
+			Preconditions.checkState(agent.getState() == State.ACTIVITY);
+			agent.doSimStep(time);
+			// ask agents about the current activity end time;
+			double currentEndTime = activityEndTimes.get(agent.getId());
+
+			if (currentEndTime == Double.POSITIVE_INFINITY) { // agent says: stop simulating me
+				unregisterAgentAtActivityLocation(agent);
+				internalInterface.getMobsim().getAgentCounter().decLiving();
+				dynAgentIter.remove();
+			} else if (currentEndTime <= time) { // the agent wants to end the activity NOW
+				unregisterAgentAtActivityLocation(agent);
+				agent.endActivityAndComputeNextState(time);
+				internalInterface.arrangeNextAgentState(agent);
+				dynAgentIter.remove();
+			}
+		}
 	}
 
 	@Override