Add tiny-hypergraph version with generated optimizations, automatically enable sparse storage

lib/core.ts

@@ -335,6 +335,18 @@ export const getTinyHyperGraphSolverOptions = (
 const compareCandidatesByF = (left: Candidate, right: Candidate) =>
   left.f - right.f
 
+export const DEFAULT_SPARSE_CANDIDATE_STORAGE_HOP_THRESHOLD = 200_000_000
+
+export const getCandidateStorageHopCount = (
+  topology: Pick<TinyHyperGraphTopology, "portCount" | "regionCount">,
+) => topology.portCount * topology.regionCount
+
+export const shouldUseSparseCandidateStorageForTopology = (
+  topology: Pick<TinyHyperGraphTopology, "portCount" | "regionCount">,
+) =>
+  getCandidateStorageHopCount(topology) >
+  DEFAULT_SPARSE_CANDIDATE_STORAGE_HOP_THRESHOLD
+
 interface SegmentGeometryScratch {
   lesserAngle: number
   greaterAngle: number
@@ -383,6 +395,20 @@ export class TinyHyperGraphSolver extends BaseSolver {
   ) {
     super()
     applyTinyHyperGraphSolverOptions(this, options)
+    const candidateStorageHopCount = getCandidateStorageHopCount(topology)
+    const shouldUseSparseCandidateStorage =
+      options?.USE_SPARSE_CANDIDATE_STORAGE ??
+      shouldUseSparseCandidateStorageForTopology(topology)
+    this.USE_SPARSE_CANDIDATE_STORAGE = shouldUseSparseCandidateStorage
+    if (shouldUseSparseCandidateStorage) {
+      this.stats = {
+        ...this.stats,
+        candidateStorageHopCount,
+        candidateStorageMode: "sparse",
+        autoSparseCandidateStorage:
+          options?.USE_SPARSE_CANDIDATE_STORAGE === undefined,
+      }
+    }
     this.state = {
       portAssignment: new Int32Array(topology.portCount).fill(-1),
       regionSegments: Array.from({ length: topology.regionCount }, () => []),

lib/section-solver/TinyHyperGraphSectionPipelineSolver.ts

@@ -48,7 +48,7 @@ const DEFAULT_SOLVE_GRAPH_OPTIONS: TinyHyperGraphSolverOptions = {
 }
 
 const DEFAULT_SECTION_SOLVER_MAX_ITERATIONS = 50_000
-const DEFAULT_SECTION_PIPELINE_MAX_ITERATIONS = 200_000
+const DEFAULT_SECTION_PIPELINE_MAX_ITERATIONS = 1_250_000
 
 const DEFAULT_SECTION_SOLVER_OPTIONS: TinyHyperGraphSectionSolverOptions = {
   DISTANCE_TO_COST: 0.05,

lib/section-solver/index.ts

@@ -593,6 +593,7 @@ class TinyHyperGraphSectionSearchSolver extends TinyHyperGraphSolver {
   baselineBeatRipCount?: number
   previousBestMaxRegionCost = Number.POSITIVE_INFINITY
   ripsSinceBestMaxRegionCostImprovement = 0
+  private prioritizeRouteIdForNextRip?: RouteId
 
   MAX_RIPS = Number.POSITIVE_INFINITY
   MAX_RIPS_WITHOUT_MAX_REGION_COST_IMPROVEMENT = Number.POSITIVE_INFINITY
@@ -672,6 +673,27 @@ class TinyHyperGraphSectionSearchSolver extends TinyHyperGraphSolver {
     this.state.goalPortId = -1
   }
 
+  getNextActiveRouteOrder(): RouteId[] {
+    const shuffledRouteIds = shuffle(
+      [...this.activeRouteIds],
+      this.state.ripCount,
+    )
+    const prioritizedRouteId = this.prioritizeRouteIdForNextRip
+    this.prioritizeRouteIdForNextRip = undefined
+
+    if (
+      prioritizedRouteId === undefined ||
+      !this.activeRouteIds.includes(prioritizedRouteId)
+    ) {
+      return shuffledRouteIds
+    }
+
+    return [
+      prioritizedRouteId,
+      ...shuffledRouteIds.filter((routeId) => routeId !== prioritizedRouteId),
+    ]
+  }
+
   override getStartingNextRegionId(
     routeId: RouteId,
     startingPortId: PortId,
@@ -687,21 +709,15 @@ class TinyHyperGraphSectionSearchSolver extends TinyHyperGraphSolver {
   override resetRoutingStateForRerip() {
     if (!this.fixedSnapshot) {
       super.resetRoutingStateForRerip()
-      this.state.unroutedRoutes = shuffle(
-        [...this.activeRouteIds],
-        this.state.ripCount,
-      )
+      this.state.unroutedRoutes = this.getNextActiveRouteOrder()
       this.applyFixedSegments()
       return
     }
 
     restoreSolvedStateSnapshot(this, this.fixedSnapshot)
     this.state.currentRouteId = undefined
     this.state.currentRouteNetId = undefined
-    this.state.unroutedRoutes = shuffle(
-      [...this.activeRouteIds],
-      this.state.ripCount,
-    )
+    this.state.unroutedRoutes = this.getNextActiveRouteOrder()
     this.state.candidateQueue.clear()
     this.resetCandidateBestCosts()
     this.state.goalPortId = -1
@@ -820,6 +836,26 @@ class TinyHyperGraphSectionSearchSolver extends TinyHyperGraphSolver {
 
   override onOutOfCandidates() {
     const { state } = this
+    const currentRouteId = state.currentRouteId
+    const failedOnFirstActiveRoute =
+      currentRouteId !== undefined &&
+      state.unroutedRoutes.length === this.activeRouteIds.length - 1
+
+    if (failedOnFirstActiveRoute) {
+      this.stats = {
+        ...this.stats,
+        activeRouteCount: this.activeRouteIds.length,
+        sectionSearchRejectedInfeasibleFirstRoute: true,
+        sectionSearchInfeasibleRouteId: currentRouteId,
+        ripCount: state.ripCount,
+      }
+      this.error = `Route ${currentRouteId} has no legal path through the section from the fixed routing state`
+      this.failed = true
+      return
+    }
+    if (currentRouteId !== undefined) {
+      this.prioritizeRouteIdForNextRip = currentRouteId
+    }
 
     for (const regionId of this.mutableRegionIds) {
       const regionCost =
@@ -1013,6 +1049,21 @@ export class TinyHyperGraphSectionSolver extends BaseSolver {
       return
     }
 
+    if (this.sectionSolver.stats.acceptedFixedSectionStateOnTimeout) {
+      this.optimizedSolver = this.baselineSolver
+      this.stats = {
+        ...this.stats,
+        initialMaxRegionCost: this.baselineSummary.maxRegionCost,
+        initialTotalRegionCost: this.baselineSummary.totalRegionCost,
+        finalMaxRegionCost: this.baselineSummary.maxRegionCost,
+        finalTotalRegionCost: this.baselineSummary.totalRegionCost,
+        optimized: false,
+        sectionSearchTimeoutFallbackToBaseline: true,
+      }
+      this.solved = true
+      return
+    }
+
     const candidateSolver = createSolvedSolverFromRegionSegments(
       this.topology,
       this.problem,

tests/solver/ddr5-dense-allocation-repro.test.ts

@@ -4,6 +4,10 @@ import {
   getSinglePortPointPathingSolverParams,
   type SerializedHyperGraphPortPointPathingSolverInput,
 } from "lib/compat/convertPortPointPathingSolverInputToSerializedHyperGraph"
+import {
+  DEFAULT_SPARSE_CANDIDATE_STORAGE_HOP_THRESHOLD,
+  TinyHyperGraphSolver,
+} from "lib/core"
 import { loadSerializedHyperGraph } from "lib/compat/loadSerializedHyperGraph"
 import { ddr5Pipeline7PortPointPathingInput } from "tiny-hypergraph-repros"
 
@@ -140,7 +144,7 @@ const addConnectionTerminalPorts = (
   }
 }
 
-test("repro: DDR5 pipeline7 port-point-pathing input implies multi-GB dense hop state", () => {
+test("repro: DDR5 pipeline7 port-point-pathing input uses sparse hop state", () => {
   const input = getSinglePortPointPathingSolverParams(
     ddr5Pipeline7PortPointPathingInput as SerializedHyperGraphPortPointPathingSolverInput,
   )
@@ -176,7 +180,18 @@ test("repro: DDR5 pipeline7 port-point-pathing input implies multi-GB dense hop
   expect(topology.regionCount).toBeGreaterThan(12_000)
   expect(topology.portCount).toBeGreaterThan(27_000)
   expect(denseHopBytes).toBeGreaterThan(4_000_000_000)
+  expect(denseHopCount).toBeGreaterThan(
+    DEFAULT_SPARSE_CANDIDATE_STORAGE_HOP_THRESHOLD,
+  )
 
-  // Do not construct TinyHyperGraphSolver in this repro: current construction
-  // attempts to allocate dense hop state at this size, which is the crash.
+  const solver = new TinyHyperGraphSolver(topology, problem)
+
+  expect(solver.USE_SPARSE_CANDIDATE_STORAGE).toBe(true)
+  expect(solver.state.candidateBestCostByHopId).toBeInstanceOf(Map)
+  expect(solver.state.candidateBestCostGenerationByHopId).toBeInstanceOf(Map)
+  expect(solver.stats).toMatchObject({
+    autoSparseCandidateStorage: true,
+    candidateStorageHopCount: denseHopCount,
+    candidateStorageMode: "sparse",
+  })
 })