Browsing by Author "Malas, T."
Now showing items 1-7 of 7
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Accelerating the multilevel fast multipole algorithm with the sparse-approximate-inverse (SAI) preconditioning
Malas, T.; Gürel, Levent (Society for Industrial and Applied Mathematics, 2009)With the help of the multilevel fast multipole algorithm, integral-equation methods can be used to solve real-life electromagnetics problems both accurately and efficiently. Increasing problem dimensions, on the other hand, ... -
Analysis of dielectric photonic-crystal problems with MLFMA and Schur-complement preconditioners
Ergül, Özgür; Malas, T.; Gürel, Levent (IEEE, 2011-01-13)We present rigorous solutions of electromagnetics problems involving 3-D dielectric photonic crystals (PhCs). Problems are formulated with recently developed surface integral equations and solved iteratively using the ... -
Fast and accurate analysis of large metamaterial structures using the multilevel fast multipole algorithm
Gürel, Levent; Ergül, Özgür; Ünal, A.; Malas, T. (2009)We report fast and accurate simulations of metamaterial structures constructed with large numbers of unit cells containing split-ring resonators and thin wires. Scattering problems involving various metamaterial walls are ... -
Incomplete LU preconditioning with the multilevel fast multipole algorithm for electromagnetic scattering
Malas, T.; Gürel, Levent (Society for Industrial and Applied Mathematics, 2007)Iterative solution of large-scale scattering problems in computational electromagnetics with the multilevel fast multipole algorithm (MLFMA) requires strong preconditioners, especially for the electric-field integral ... -
Iterative near-field preconditioner for the multilevel fast multipole algorithm
Gürel, Levent; Malas, T. (Society for Industrial and Applied Mathematics, 2010-07-06)For iterative solutions of large and difficult integral-equation problems in computational electromagnetics using the multilevel fast multipole algorithm (MLFMA), preconditioners are usually built from the available sparse ... -
Parallel image restoration using surrogate constraint methods
Uçar, B.; Aykanat, Cevdet; Pınar, M. Ç.; Malas, T. (Academic Press, 2007)When formulated as a system of linear inequalities, the image restoration problem yields huge, unstructured, sparse matrices even for images of small size. To solve the image restoration problem, we use the surrogate ... -
Solutions of large-scale electromagnetics problems using an iterative inner-outer scheme with ordinary and approximate multilevel fast multipole algorithms
Ergül, A.; Malas, T.; Gürel, Levent (2010)We present an iterative inner-outer scheme for the efficient solution of large-scale electromagnetics problems involving perfectly-conducting objects formulated with surface integral equations. Problems are solved by ...