Rewrite

- rewritten all the sim code in a way to make easier to read and collect stats
2025-01-17 12:29:47 +01:00
parent f0b6cbfba3
commit 0d541f7737
5 changed files with 302 additions and 1 deletions
--- a/src/main/java/net/berack/upo/valpre/NetSimulation.java
+++ b/src/main/java/net/berack/upo/valpre/NetSimulation.java
@@ -0,0 +1,123 @@
+package net.berack.upo.valpre;
+
+import java.util.ArrayDeque;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.PriorityQueue;
+import net.berack.upo.valpre.rand.Rng;
+
+public class NetSimulation {
+    public final long seed;
+    private final Rng rng;
+    private final Map<String, ServerNode> servers = new HashMap<>();
+
+    public NetSimulation(long seed) {
+        this.seed = seed;
+        this.rng = new Rng(seed);
+    }
+
+    public void addNode(ServerNode node) {
+        this.servers.put(node.name, node);
+    }
+
+    public Map<String, Statistics> run(long total, String untilDepartureNode) {
+        // Initialization
+        var timeNow = 0.0d;
+        var stats = new HashMap<String, Statistics>();
+        var fel = new PriorityQueue<Event>();
+        for (var node : this.servers.values()) {
+            var s = new Statistics(this.rng);
+            s.addArrivalIf(node.isSource, node, timeNow, fel);
+            stats.put(node.name, s);
+        }
+
+        // Main Simulation Loop
+        var nodeStop = stats.get(untilDepartureNode);
+        while (nodeStop.numDepartures < total) {
+            var event = fel.poll();
+            if (event == null) {
+                break;
+            }
+
+            timeNow = event.time;
+            var statsNode = stats.get(event.node.name);
+            switch (event.type) {
+                case ARRIVAL -> statsNode.processArrival(event, timeNow, fel);
+                case DEPARTURE -> statsNode.processDeparture(event, timeNow, fel);
+            }
+        }
+        return stats;
+    }
+
+    public static class Statistics {
+        public int numArrivals = 0;
+        public int numDepartures = 0;
+        public int maxQueueLength = 0;
+        public double busyTime = 0.0;
+        public double responseTime = 0.0;
+        public double lastEventTime = 0.0;
+
+        private int numServerBusy = 0;
+        private ArrayDeque<Double> queue = new ArrayDeque<>();
+        private final Rng rng;
+
+        public Statistics(Rng rng) {
+            this.rng = rng;
+        }
+
+        public void reset() {
+            this.numArrivals = 0;
+            this.numDepartures = 0;
+            this.numServerBusy = 0;
+            this.busyTime = 0.0;
+            this.responseTime = 0.0;
+            this.queue.clear();
+        }
+
+        private void processArrival(Event event, double timeNow, PriorityQueue<Event> fel) {
+            this.numArrivals++;
+            this.queue.add(event.time);
+            this.maxQueueLength = Math.max(this.maxQueueLength, this.queue.size());
+
+            if (event.node.maxServers > this.numServerBusy) {
+                this.numServerBusy++;
+                var time = event.node.distribution.sample(this.rng);
+                var departure = Event.newDeparture(event.node, timeNow + time);
+                fel.add(departure);
+            } else {
+                this.busyTime += timeNow - this.lastEventTime;
+            }
+            this.lastEventTime = timeNow;
+
+            this.addArrivalIf(event.node.isSource, event.node, timeNow, fel);
+        }
+
+        private void processDeparture(Event event, double timeNow, PriorityQueue<Event> fel) {
+            var startService = this.queue.poll();
+            var response = timeNow - startService;
+
+            if (this.queue.size() < this.numServerBusy) {
+                this.numServerBusy--;
+            } else {
+                var time = event.node.distribution.sample(this.rng);
+                var departure = Event.newDeparture(event.node, timeNow + time);
+                fel.add(departure);
+            }
+
+            this.numDepartures++;
+            this.responseTime += response;
+            this.busyTime += timeNow - this.lastEventTime;
+            this.lastEventTime = timeNow;
+
+            var next = event.node.getChild(rng);
+            this.addArrivalIf(!event.node.isSink, next, timeNow, fel);
+        }
+
+        private void addArrivalIf(boolean condition, ServerNode node, double timeNow, PriorityQueue<Event> fel) {
+            if (condition && node != null) {
+                var delay = node.distribution.sample(this.rng);
+                fel.add(Event.newArrival(node, timeNow + delay));
+            }
+        }
+    }
+}