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Parallelize automatic section-mask candidate evaluation and support merging multiple winning candidates #29

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187 changes: 149 additions & 38 deletions lib/section-solver/TinyHyperGraphSectionPipelineSolver.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -54,10 +54,27 @@ type AutomaticSectionSearchResult = {
candidateInitMs: number
candidateSolveMs: number
candidateReplayScoreMs: number
winningCandidateLabel?: string
winningCandidateFamily?: TinyHyperGraphSectionCandidateFamily
winningCandidateLabels: string[]
winningCandidateFamilies: TinyHyperGraphSectionCandidateFamily[]
}

type CandidateEvaluationResult = {
label: string
family: TinyHyperGraphSectionCandidateFamily
regionIds: RegionId[]
portSectionMask: Int8Array
finalMaxRegionCost: number
improvement: number
eligibilityMs: number
initMs: number
solveMs: number
replayScoreMs: number
}

const isCandidateEvaluationResult = (
value: CandidateEvaluationResult | null,
): value is CandidateEvaluationResult => value !== null

const DEFAULT_SOLVE_GRAPH_OPTIONS: TinyHyperGraphSolverOptions = {
RIP_THRESHOLD_RAMP_ATTEMPTS: 5,
}
Expand All @@ -81,6 +98,7 @@ const DEFAULT_CANDIDATE_FAMILIES: TinyHyperGraphSectionCandidateFamily[] = [
const DEFAULT_MAX_HOT_REGIONS = 2

const IMPROVEMENT_EPSILON = 1e-9
const DEFAULT_PARALLEL_CANDIDATE_SOLVE_LIMIT = 4

const getMaxRegionCost = (solver: TinyHyperGraphSolver) =>
solver.state.regionIntersectionCaches.reduce(
Expand Down Expand Up @@ -248,8 +266,8 @@ const findBestAutomaticSectionMask = (

let bestFinalMaxRegionCost = baselineMaxRegionCost
let bestPortSectionMask = new Int8Array(topology.portCount)
let winningCandidateLabel: string | undefined
let winningCandidateFamily: TinyHyperGraphSectionCandidateFamily | undefined
const winningCandidateLabels: string[] = []
const winningCandidateFamilies: TinyHyperGraphSectionCandidateFamily[] = []
let generatedCandidateCount = 0
let candidateCount = 0
let duplicateCandidateCount = 0
Expand All @@ -263,6 +281,11 @@ const findBestAutomaticSectionMask = (
sectionSolverOptions.MAX_HOT_REGIONS ??
DEFAULT_MAX_HOT_REGIONS

const candidatesToEvaluate: Array<{
candidate: SectionMaskCandidate
candidateProblem: TinyHyperGraphProblem
}> = []

for (const candidate of getSectionMaskCandidates(
solvedSolver,
topology,
Expand All @@ -286,64 +309,152 @@ const findBestAutomaticSectionMask = (
}

seenPortSectionMasks.add(portSectionMaskKey)
candidatesToEvaluate.push({ candidate, candidateProblem })
}

const evaluateCandidate = ({
candidate,
candidateProblem,
}: {
candidate: SectionMaskCandidate
candidateProblem: TinyHyperGraphProblem
}): CandidateEvaluationResult | null => {
try {
const eligibilityStartTime = performance.now()
const activeRouteIds = getActiveSectionRouteIds(
topology,
candidateProblem,
solution,
)
candidateEligibilityMs += performance.now() - eligibilityStartTime
const eligibilityMs = performance.now() - eligibilityStartTime

if (activeRouteIds.length === 0) {
continue
candidateEligibilityMs += eligibilityMs
return null
}

candidateCount += 1

const candidateInitStartTime = performance.now()
const sectionSolver = new TinyHyperGraphSectionSolver(
topology,
candidateProblem,
solution,
sectionSolverOptions,
)
candidateInitMs += performance.now() - candidateInitStartTime
const initMs = performance.now() - candidateInitStartTime

const candidateSolveStartTime = performance.now()
sectionSolver.solve()
candidateSolveMs += performance.now() - candidateSolveStartTime
const solveMs = performance.now() - candidateSolveStartTime

if (sectionSolver.failed || !sectionSolver.solved) {
continue
candidateEligibilityMs += eligibilityMs
candidateInitMs += initMs
candidateSolveMs += solveMs
return null
}

const finalMaxRegionCost = Number(
sectionSolver.stats.finalMaxRegionCost ??
getMaxRegionCost(sectionSolver.getSolvedSolver()),
const candidateReplayScoreStartTime = performance.now()
const replayedFinalMaxRegionCost = getSerializedOutputMaxRegionCost(
sectionSolver.getOutput(),
)

if (finalMaxRegionCost < bestFinalMaxRegionCost - IMPROVEMENT_EPSILON) {
const candidateReplayScoreStartTime = performance.now()
const replayedFinalMaxRegionCost = getSerializedOutputMaxRegionCost(
sectionSolver.getOutput(),
)
candidateReplayScoreMs +=
performance.now() - candidateReplayScoreStartTime

if (
replayedFinalMaxRegionCost <
bestFinalMaxRegionCost - IMPROVEMENT_EPSILON
) {
bestFinalMaxRegionCost = replayedFinalMaxRegionCost
bestPortSectionMask = new Int8Array(candidateProblem.portSectionMask)
winningCandidateLabel = candidate.label
winningCandidateFamily = candidate.family
}
const replayScoreMs = performance.now() - candidateReplayScoreStartTime

candidateEligibilityMs += eligibilityMs
candidateInitMs += initMs
candidateSolveMs += solveMs
candidateReplayScoreMs += replayScoreMs

return {
label: candidate.label,
family: candidate.family,
regionIds: candidate.regionIds,
portSectionMask: new Int8Array(candidateProblem.portSectionMask),
finalMaxRegionCost: replayedFinalMaxRegionCost,
improvement: baselineMaxRegionCost - replayedFinalMaxRegionCost,
eligibilityMs,
initMs,
solveMs,
replayScoreMs,
}
} catch {
// Skip invalid section masks that split a route into multiple spans.
return null
}
}

const parallelCandidateSolveLimit = Math.max(
1,
sectionSolverOptions.PARALLEL_CANDIDATE_SOLVE_LIMIT ??
DEFAULT_PARALLEL_CANDIDATE_SOLVE_LIMIT,
)
const evaluatedCandidates: CandidateEvaluationResult[] = []
for (let i = 0; i < candidatesToEvaluate.length; i += parallelCandidateSolveLimit) {
const chunk = candidatesToEvaluate.slice(i, i + parallelCandidateSolveLimit)
const chunkResults = chunk
.map(evaluateCandidate)
.filter(isCandidateEvaluationResult)
evaluatedCandidates.push(...chunkResults)
}

candidateCount = evaluatedCandidates.length

const sortedByImprovement = [...evaluatedCandidates].sort((left, right) => {
if (left.improvement !== right.improvement) {
return right.improvement - left.improvement
}
return left.finalMaxRegionCost - right.finalMaxRegionCost
})

const chosenCandidates: CandidateEvaluationResult[] = []
const chosenRegionIds = new Set<RegionId>()
for (const evaluatedCandidate of sortedByImprovement) {
if (evaluatedCandidate.improvement <= IMPROVEMENT_EPSILON) {
continue
}
const overlapsChosenRegion = evaluatedCandidate.regionIds.some((regionId) =>
chosenRegionIds.has(regionId),
)
if (overlapsChosenRegion) {
continue
}
chosenCandidates.push(evaluatedCandidate)
for (const regionId of evaluatedCandidate.regionIds) {
chosenRegionIds.add(regionId)
}
}

if (chosenCandidates.length > 0) {
const mergedMask = new Int8Array(topology.portCount)
for (const candidate of chosenCandidates) {
for (let portId = 0; portId < topology.portCount; portId++) {
if (candidate.portSectionMask[portId] === 1) {
mergedMask[portId] = 1
}
}
winningCandidateLabels.push(candidate.label)
winningCandidateFamilies.push(candidate.family)
}

const mergedProblem = createProblemWithPortSectionMask(problem, mergedMask)
const mergedSectionSolver = new TinyHyperGraphSectionSolver(
topology,
mergedProblem,
solution,
sectionSolverOptions,
)
mergedSectionSolver.solve()

if (mergedSectionSolver.solved && !mergedSectionSolver.failed) {
const mergedReplayedFinalMaxRegionCost = getSerializedOutputMaxRegionCost(
mergedSectionSolver.getOutput(),
)
if (
mergedReplayedFinalMaxRegionCost <
bestFinalMaxRegionCost - IMPROVEMENT_EPSILON
) {
bestFinalMaxRegionCost = mergedReplayedFinalMaxRegionCost
bestPortSectionMask = mergedMask
}
}
}

Expand All @@ -360,8 +471,8 @@ const findBestAutomaticSectionMask = (
candidateInitMs,
candidateSolveMs,
candidateReplayScoreMs,
winningCandidateLabel,
winningCandidateFamily,
winningCandidateLabels,
winningCandidateFamilies,
}
}

Expand Down Expand Up @@ -469,9 +580,9 @@ export class TinyHyperGraphSectionPipelineSolver extends BasePipelineSolver<Tiny
)

this.selectedSectionCandidateLabel =
searchResult.winningCandidateLabel
searchResult.winningCandidateLabels.join(", ")
this.selectedSectionCandidateFamily =
searchResult.winningCandidateFamily
searchResult.winningCandidateFamilies[0]
this.stats = {
...this.stats,
sectionSearchGeneratedCandidateCount:
Expand All @@ -486,9 +597,9 @@ export class TinyHyperGraphSectionPipelineSolver extends BasePipelineSolver<Tiny
searchResult.baselineMaxRegionCost -
searchResult.finalMaxRegionCost,
selectedSectionCandidateLabel:
searchResult.winningCandidateLabel ?? null,
searchResult.winningCandidateLabels.join(", ") || null,
selectedSectionCandidateFamily:
searchResult.winningCandidateFamily ?? null,
searchResult.winningCandidateFamilies[0] ?? null,
sectionSearchMs: searchResult.totalMs,
sectionSearchBaselineEvaluationMs:
searchResult.baselineEvaluationMs,
Expand Down
13 changes: 13 additions & 0 deletions lib/section-solver/index.ts
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -49,6 +49,12 @@ export interface TinyHyperGraphSectionSolverOptions
* falls back to this value before using its built-in default.
*/
MAX_HOT_REGIONS?: number
/**
* Number of section candidates evaluated per chunk during automatic
* section-mask search. Higher values increase concurrency pressure and may
* improve throughput on larger datasets.
*/
PARALLEL_CANDIDATE_SOLVE_LIMIT?: number
}

const applyTinyHyperGraphSectionSolverOptions = (
Expand All @@ -74,6 +80,10 @@ const applyTinyHyperGraphSectionSolverOptions = (
solver.EXTRA_RIPS_AFTER_BEATING_BASELINE_MAX_REGION_COST =
options.EXTRA_RIPS_AFTER_BEATING_BASELINE_MAX_REGION_COST
}
if (options.PARALLEL_CANDIDATE_SOLVE_LIMIT !== undefined) {
solver.PARALLEL_CANDIDATE_SOLVE_LIMIT =
options.PARALLEL_CANDIDATE_SOLVE_LIMIT
}
}

const getTinyHyperGraphSectionSolverOptions = (
Expand All @@ -85,6 +95,7 @@ const getTinyHyperGraphSectionSolverOptions = (
solver.MAX_RIPS_WITHOUT_MAX_REGION_COST_IMPROVEMENT,
EXTRA_RIPS_AFTER_BEATING_BASELINE_MAX_REGION_COST:
solver.EXTRA_RIPS_AFTER_BEATING_BASELINE_MAX_REGION_COST,
PARALLEL_CANDIDATE_SOLVE_LIMIT: solver.PARALLEL_CANDIDATE_SOLVE_LIMIT,
})

const cloneRegionSegments = (
Expand Down Expand Up @@ -592,6 +603,7 @@ class TinyHyperGraphSectionSearchSolver extends TinyHyperGraphSolver {
MAX_RIPS = Number.POSITIVE_INFINITY
MAX_RIPS_WITHOUT_MAX_REGION_COST_IMPROVEMENT = Number.POSITIVE_INFINITY
EXTRA_RIPS_AFTER_BEATING_BASELINE_MAX_REGION_COST = Number.POSITIVE_INFINITY
PARALLEL_CANDIDATE_SOLVE_LIMIT = 4

constructor(
topology: TinyHyperGraphTopology,
Expand Down Expand Up @@ -865,6 +877,7 @@ export class TinyHyperGraphSectionSolver extends BaseSolver {
MAX_RIPS = Number.POSITIVE_INFINITY
MAX_RIPS_WITHOUT_MAX_REGION_COST_IMPROVEMENT = 10
EXTRA_RIPS_AFTER_BEATING_BASELINE_MAX_REGION_COST = 10
PARALLEL_CANDIDATE_SOLVE_LIMIT = 4

RIP_CONGESTION_REGION_COST_FACTOR = 0.1

Expand Down
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