From af4d8acc6efbade15f60ea93736c7e9cba7fe58d Mon Sep 17 00:00:00 2001
From: ShiboSoftwareDev <shibosoftwaredev@gmail.com>
Date: Sun, 2 Aug 2026 23:58:18 +0200
Subject: [PATCH 1/2] experiment: refresh directed guidance for occupied ports

---
 lib/core.ts                         | 14 ++++++++++++++
 lib/directed-route-hop-heuristic.ts |  7 +++++++
 2 files changed, 21 insertions(+)

diff --git a/lib/core.ts b/lib/core.ts
index 748d6d6..47e158f 100644
--- a/lib/core.ts
+++ b/lib/core.ts
@@ -578,6 +578,20 @@ export class TinyHyperGraphSolver extends BaseSolver {
 
       this.resetCandidateBestCosts()
       const startingPortId = problem.routeStartPort[state.currentRouteId!]
+      const endingPortId = problem.routeEndPort[state.currentRouteId!]
+
+      if (topology.portZ[startingPortId] !== topology.portZ[endingPortId]) {
+        this.problemSetup.directedHopCountToEndByRoute[state.currentRouteId!] =
+          createDirectedRouteHopHeuristic({
+            topology,
+            problem,
+            portEndpointReservationNetId:
+              this.problemSetup.portEndpointReservationNetId,
+            portAssignment: state.portAssignment,
+            routeId: state.currentRouteId!,
+          })
+      }
+
       state.candidateQueue.clear()
       const startingNextRegionId = this.getStartingNextRegionId(
         state.currentRouteId!,
diff --git a/lib/directed-route-hop-heuristic.ts b/lib/directed-route-hop-heuristic.ts
index aa7a97d..fe02f1b 100644
--- a/lib/directed-route-hop-heuristic.ts
+++ b/lib/directed-route-hop-heuristic.ts
@@ -7,6 +7,7 @@ interface CreateDirectedRouteHopHeuristicContext {
   topology: TinyHyperGraphTopology
   problem: TinyHyperGraphProblem
   portEndpointReservationNetId: Int32Array
+  portAssignment?: Int32Array
   routeId: RouteId
 }
 
@@ -33,11 +34,15 @@ const isRegionAvailableToNet = (
 const isPortAvailableToNet = (
   problem: TinyHyperGraphProblem,
   portEndpointReservationNetId: Int32Array,
+  portAssignment: Int32Array | undefined,
   routeNetId: NetId,
   portId: PortId,
 ) => {
   if (problem.portSectionMask[portId] === 0) return false
 
+  const assignedNetId = portAssignment?.[portId] ?? -1
+  if (assignedNetId !== -1 && assignedNetId !== routeNetId) return false
+
   const reservedNetId = portEndpointReservationNetId[portId] ?? -1
   return reservedNetId === -1 || reservedNetId === routeNetId
 }
@@ -51,6 +56,7 @@ export const createDirectedRouteHopHeuristic = ({
   topology,
   problem,
   portEndpointReservationNetId,
+  portAssignment,
   routeId,
 }: CreateDirectedRouteHopHeuristicContext): Int32Array => {
   const hopCountToGoal = new Int32Array(topology.portCount * 2).fill(
@@ -96,6 +102,7 @@ export const createDirectedRouteHopHeuristic = ({
       !isPortAvailableToNet(
         problem,
         portEndpointReservationNetId,
+        portAssignment,
         routeNetId,
         exitPortId,
       )

From bb702a8446b256ec979fb8a49ba3cfbf7ab7603e Mon Sep 17 00:00:00 2001
From: ShiboSoftwareDev <shibosoftwaredev@gmail.com>
Date: Mon, 3 Aug 2026 00:00:35 +0200
Subject: [PATCH 2/2] experiment: reject unreachable directed states

---
 lib/core.ts | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/core.ts b/lib/core.ts
index 47e158f..383427a 100644
--- a/lib/core.ts
+++ b/lib/core.ts
@@ -683,6 +683,7 @@ export class TinyHyperGraphSolver extends BaseSolver {
       }
 
       const h = this.computeH(neighborPortId, nextRegionId)
+      if (!Number.isFinite(h)) continue
 
       const newCandidate = {
         prevRegionId: currentCandidate.nextRegionId,