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Method of Particles as a Universal Solver Witold Dzwinel AGH - Department of Computer Science Dzwinel W, Alda W, Kitowski J, Yuen DA, Molecular Simulation, 20/6, 361-384 2000 Dzwinel W, Future Generation Computer Systems, 12, 371-389, 1997 Dzwinel W, Yuen DA, Boryczko K, Chemical Engineering Sci., 61, 2169-2185, 2006.
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Universal solver = automata or a formalism having universal computational capabilities (equivalent to TM, or lambda calculus or 110 Wolfram rule) = paradigm, which can be a common platform of an offspring of algorithms designated for solving a broad class of seemingly unrelated problems from e.g. modeling and simulation (PM, CA, ANN, MA …) optimization (GA, SA, ANN, PM, MA …) learning theory and systems (ANN, GA …) etc.
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Method of particles – in simulation and modeling The algorithms employing moving and interacting particles as primitives. Taxonomy due to definition of particle (quark, atom, molecule, granule, cluster, chunk of something, item, many items, galaxies etc) definition of interactions (hard, soft: pair, manybody, multipole) moving scheme (deterministic, stochastic) granularity (?) of space and time continuous/continuous (MD, DPD, FPM, SC-DPD, SPH) continuous/discrete (hard spheres, DSMC) discrete/continuous (lattice dynamical systems) discrete/discrete (LG, LBG, percolation, DLA etc.) http://www.amara.com/papers/nbody.html#p3m
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Method of particles – in simulation and modeling Boryczko K, Dzwinel W, Yuen DA, J Mol. Modeling,8,33-45,2002
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Method of particles – in simulation and modeling Dzwinel W, Boryczko K, Yuen DA, Finely Dispersed Particles: Micro-, Nano-, and Atto-Engineering A.M. Spasic & J.P. Hsu eds., Taylor&Francis, CRC Press, 715-778, 2006
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Fluid Particles Flekkoy and Coveney, 1999 Serrano and Espanol, 2002
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Method of particles – in simulation and modeling Boryczko K, Dzwinel W, Yuen DA, J Mol. Modeling,9,16-33,2003 Dzwinel W, Boryczko K, Yuen DA, J Colloid Int Sci, 258/1, 163-173, 2003
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Method of particles – in graphics www.graphics.stanford.edu/.../vortex_particle-sig05/
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Method of particles – crowding Helbing D., Farkas I., Vicsek T., Nature, Vol. 407, pp. 487-490. 2000
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Method of particles – crowding
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Two groups of people running from opposite directions
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Optimization - L-J cluster http://www.uniovi.es/qcg/d-MolSym/LJ1/
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Global minimum search http://www.mat.univie.ac.at/~neum/glopt.html
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Global minimum search - particles
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GA vs. MD - global minimum of N-D function (N~10) Many interacting solutions (particles) the lowest can attract stronger the higher others Clustering around wells Bad derivatives approach (mimics annealing process)
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Bad derivative method
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GA vs. MD - global minimum of N-D function parents domain searched final cluster of particles in minimum well Jasińska-Suwada, A., Dzwinel, W., Rozmus, K., Sołtysiak, J., Computer Science, 2, 13-51, 2000
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… more dimensions?? More advanced version of coordinate decent scheme Problems when irregular and x i have very different domains Needs regularization and normalization procedures Additional difficulties with gradient calculations Best fit: is the sum of simple functions, like in MD, the total force acting on a single particle
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Multi-dimensional scaling – not a trivial example The MDS mapping from D-dimensional space to d- dimensional (D>>d) consists in minimization of the quadratic loss function, called “the stress function”: where C N and w ij are free parameters, which depend on the MDS goals. Smaller values of the “stress function“ mean better correspondence between source and target data structures.
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Multi-dimensional scaling – not a trivial example 1.Dzwinel W, Blasiak J, Future Generation Computers Systems, 15, 365-379, 1999
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Examples – periodic boundary conditions Arodz, Boryczko, Dzwinel, Kurdziel, Yuen: IEEE Visualization 2005: 90
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Examples - mammograms
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Examples - earthquakes Yuen, W. Dzwinel, Yehuda Ben-Zion, B.Kadlec, Encyclopedia of Complexity and System Science, Springer Verlag, 2007
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