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
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
PSO: Fernandes et al. 2Particle Swarm optimizationParticle Swarm optimization
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.
PSO: Fernandes et al. 5A bit ofA bit ofthis andthis andthatthatVon Neumann
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.
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
PSO: Fernandes et al. 8Comparison with static vN: best fitnessComparison with static vN: best fitness
PSO: Fernandes et al. 9Comparison with static vN: iterationsComparison with static vN: iterations
PSO: Fernandes et al. 10Comparison with l/gbestComparison with l/gbest
PSO: Fernandes et al. 11Comparison with l/gbest:Comparison with l/gbest:iterationsiterations
PSO: Fernandes et al. 12Iterations to solution inIterations to solution insuccessful runssuccessful runsVN faster than lbest, sometimes also faster than gbest
PSO: Fernandes et al. 13vN vNR lB gB01020304050successRank by success rateRank by success rate
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
PSO: Fernandes et al. 1615911717523329134940746552358163969775581387192998705101520253035k=1 k=2 k=3 k=4 k=5iterations, tnumberofparticlesEvolution of connectivity
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.
PSO: Fernandes et al. 18Thats allThats allAny questions?Any questions?Check us out atCheck us out at@geneura@geneura@canubeproject@canubeprojectANYSELFAnyselfProject@AnyselfProject
A particular slide catching your eye?
Clipping is a handy way to collect important slides you want to go back to later.