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Published byΜάρκος Μαρής Modified over 6 years ago
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Plan Introduction to multilevel heuristics Rich partitioning problems
New coarsening algorithm and applications Minipart partitioner Partitioning with general-purpose solvers
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Graph partitioning
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Graph partitioning Allocate nodes to bins Minimize # edges cut
Capacity constraints Model in High Performance Computing Electronic design …
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Multilevel algorithms
Uncoarsening + local search Local search + coarsening
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Coarsening Heavy-edge matching
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Coarsening Heavy-edge matching
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Coarsening Avoid huge nodes Handle "stars"
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Local search Move one node at a time Steepest descent
Incremental gain computation Fiduccia-Mattheyses algorithm
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A rich problem: task allocation
Bins Graph Task1 CPU Mem Task2 Communication Task3 CPU Mem Task4 … …
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A rich problem: task allocation
Bins Graph Task1 CPU Mem Task2 Multiple resources Task3 CPU Mem Task4 … …
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A rich problem: task allocation
Bins Graph Require Task1 CPU Dynlib1 Mem Task2 Task3 Dynlib2 CPU Mem Task4 … … Facility opening effect
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A rich problem: task allocation
Bins Graph Task1 Communication Resource usage CPU Mem Task2 Task3 CPU Mem Task4 … …
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A rich problem: task allocation
Mem CPU Mem CPU Distance matters 2 links Mem CPU
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A rich problem: task allocation
Mem CPU Latency Vs Throughput) Mem CPU Mem CPU
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A rich problem: task allocation
Mem CPU Mem CPU Direction matters Mem CPU
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Limitations of the coarsening approach
Assumes a well connected landscape Trivial feasibility Simple moves from solution to solution Assumes the graph structure is known Not possible for general-purpose solvers Misses other problem-specific structures
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But general-purpose solvers are stuck
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Search-driven coarsening
Coarsen without looking at the problem at all! Not specific to a problem type No need to know the graph Perfect for general-purpose solvers
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Search-driven coarsening
n solutions Node Solution #1 Solution #2 Solution #3 #1 2 #2 1 #3 #4 #5 #6 Merged
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Application: Minipart
Open-source partitioning tool Uses search-driven coarsening Quality similar to best Hmetis results
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Challenge: partitioning with a solver
No information on the problem type No special datastructure
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Application: partitioning with LocalSolver
Python script using LocalSolver 7.5 Multiple runs of LocalSolver generate solutions + Search-driven coarsening add new constraints
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Not stuck anymore!
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Beyond benchmarks Partitioning with node replication
Typical problem in electronics Ad-hoc algorithms labor-intensive 100 lines model + script
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Conclusion New method Simple to implement Any solver
Any partitioning problem Future work Computing overhead Local search could be faster
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Questions
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Links Minipart: Partitioning script: Minipart posts:
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