A study on Time-Varying Partially Connected Topologies for the Particle Swarm


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Article presented at CEC 2013 by Fernandes, Merelo, Laredo, Cotta and Rosa.

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  • Imagen de fondo de Simon Strandgaard en http://www.flickr.com/photos/12739382@N04/2411501455/
  • This slide is taken from http://www.slideshare.net/many87/pso-apiems2009ppt and reproduced using the free license of that presentation.
  • Problem with gbest is that it usually get stuck, but it's very fast, lbest is slower, but it is usually able to find the solution.
  • A study on Time-Varying Partially Connected Topologies for the Particle Swarm

    1. 1. A Study on Time-varying PartiallyA Study on Time-varying PartiallyConnectedConnectedTopologies for the Particle SwarmTopologies for the Particle SwarmFernandes, Merelo, Laredo, Cotta, RosaUGR+UMA+UNILU+IST
    2. 2. PSO: Fernandes et al. 2Particle Swarm optimizationParticle Swarm optimization
    3. 3. PSO: Fernandes et al. 3No formula here, get a move onNo formula here, get a move on● Movement combines inertia term with followingthe best.● The best is a term that depends on populationtopology.● You only follow the best if you know about it.● Different population structures are defined.
    4. 4. PSO: Fernandes et al. 4Act local, think globalAct local, think globalLBestGBest
    5. 5. PSO: Fernandes et al. 5A bit ofA bit ofthis andthis andthatthatVon Neumann
    6. 6. PSO: Fernandes et al. 6A dynamic, partially connected,A dynamic, partially connected,population structurepopulation structure● Nodes move every timestep to one of thenodes in their Moore Neighborhood, if theresone available.
    7. 7. PSO: Fernandes et al. 7Testing the new populatonTesting the new populatonstructurestructure● Using the usual Sphere, Rosenbrock, Rastrigin,Griewank and Schaffer functions.● Best fitness at the origin.● Multimodal.●Usually difficult for gbest
    8. 8. PSO: Fernandes et al. 8Comparison with static vN: best fitnessComparison with static vN: best fitness
    9. 9. PSO: Fernandes et al. 9Comparison with static vN: iterationsComparison with static vN: iterations
    10. 10. PSO: Fernandes et al. 10Comparison with l/gbestComparison with l/gbest
    11. 11. PSO: Fernandes et al. 11Comparison with l/gbest:Comparison with l/gbest:iterationsiterations
    12. 12. PSO: Fernandes et al. 12Iterations to solution inIterations to solution insuccessful runssuccessful runsVN faster than lbest, sometimes also faster than gbest
    13. 13. PSO: Fernandes et al. 13vN vNR lB gB01020304050successRank by success rateRank by success rate
    14. 14. PSO: Fernandes et al. 140.5 1 1.5 2 2.5 3 3.5 4 4.5 5vNRvNlBgBrankRank by overall performanceRank by overall performance
    15. 15. PSO: Fernandes et al. 151 2 3 4 50481216207x7 8x89x9 10x10Connectivity histogram.
    16. 16. PSO: Fernandes et al. 1615911717523329134940746552358163969775581387192998705101520253035k=1 k=2 k=3 k=4 k=5iterations, tnumberofparticlesEvolution of connectivity
    17. 17. PSO: Fernandes et al. 17ConclusionsConclusions● Dynamic and partially connected structuresoffer the best of both worlds.● Size of the grid is not critical, but as a rule ofthumb: 2 x number of particles.● Dynamic structures are better than static.
    18. 18. PSO: Fernandes et al. 18Thats allThats allAny questions?Any questions?Check us out atCheck us out at@geneura@geneura@canubeproject@canubeprojectANYSELFAnyselfProject@AnyselfProject