Dissertations / Theses on the topic 'Multigrid methods (Numerical analysis)'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Multigrid methods (Numerical analysis).'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
Au, Wing-hoi. "Numerical generation of body-fitted coordinates by multigrid method /." [Hong Kong] : University of Hong Kong, 1990. http://sunzi.lib.hku.hk/hkuto/record.jsp?B1296637X.
Full text區榮海 and Wing-hoi Au. "Numerical generation of body-fitted coordinates by multigrid method." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1990. http://hub.hku.hk/bib/B31209555.
Full text吳朝安 and Chiu-on Ng. "Simulation of initial stage of water impact on 2-D members with multigridded volume of fluid method." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1990. http://hub.hku.hk/bib/B31209361.
Full textNg, Chiu-on. "Simulation of initial stage of water impact on 2-D members with multigridded volume of fluid method /." Hong Kong : University of Hong Kong, 1990. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12758073.
Full textLarson, Gregory J. "Performance of algebraic multigrid for parallelized finite element DNS/LES solvers /." Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1559.pdf.
Full textEaton, Frank Joseph. "A multigrid preconditioner for two-phase flow in porous media." Access restricted to users with UT Austin EID Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3036595.
Full textPeacock, Darren. "Parallelized multigrid applied to modeling molecular electronics." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=101160.
Full textOne of the difficulties of ab-initio calculations is that they can be extremely costly in terms of the computing time and memory that they require. For this reason, in addition to using appropriate approximations, sophisticated numerical analysis tech niques need to be used. One of the bottlenecks in the NEGF-DFT method is solving the Poisson equation on a large real space grid. For studying systems incorporating a gate voltage it is required to be able to solve this problem with nonperiodic boundary conditions. In order to do this a technique called multigrid is used. This thesis examines the multigrid technique and develops an efficient implementation for the purpose of use in the NEGF-DFT formalism. For large systems, where it is necessary to use especially large real space grids, it is desirable to run simulations on parallel computing clusters to handle the memory requirements and make the code run faster. For this reason a parallel implementation of multigrid is developed and tested for performance. The multigrid tool is incorporated into the NEGF-DFT formalism and tested to ensure that it is properly implemented. A few calculations are made on a benzenedithiol system with gold leads to show the effect of an applied gate voltage.
Chen, Yujia. "Geometric multigrid and closest point methods for surfaces and general domains." Thesis, University of Oxford, 2015. http://ora.ox.ac.uk/objects/uuid:56a3bf12-ff09-4ea5-b406-9d77054770e2.
Full textCarter, Paul M. "A multigrid method for determining the deflection of lithospheric plates." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/27854.
Full textScience, Faculty of
Mathematics, Department of
Graduate
Iwamura, Chihiro, and chihiro_iwamura@ybb ne jp. "A fast solver for large systems of linear equations for finite element analysis on unstructured meshes." Swinburne University of Technology, 2004. http://adt.lib.swin.edu.au./public/adt-VSWT20051020.091538.
Full textPadgett, James D. "Effectiveness of Additive Correction Multigrid in numerical heat transfer analysis when implemented on an Intel IPSC2." PDXScholar, 1992. https://pdxscholar.library.pdx.edu/open_access_etds/4429.
Full textNapov, Artem. "Algebraic analysis of V-cycle multigrid and aggregation-based two-grid methods." Doctoral thesis, Universite Libre de Bruxelles, 2010. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210175.
Full textChapter 2 considers more precisely the well-known V-cycle convergence theories: the approximation property based analyses by Hackbusch (see [Multi-Grid Methods and Applications, 1985, pp.164-167]) and by McCormick [SIAM J.Numer.Anal. vol.22(1985), pp.634-643] and the successive subspace correction theory, as presented in [SIAM Review, vol.34(1992), pp.581-613] by Xu and in [Acta Numerica, vol.2(1993), pp.285-326.] by Yserentant. Under the constraint that the resulting upper bound on the convergence rate must be expressed with respect to parameters involving two successive levels at a time, these theories are compared. Unlike [Acta Numerica, vol.2(1993), pp.285-326.], where the comparison is performed on the basis of underlying assumptions in a particular PDE context, we compare directly the upper bounds. We show that these analyses are equivalent from the qualitative point of view. From the quantitative point of view,
we show that the bound due to McCormick is always the best one.
When the upper bound on the V-cycle convergence factor involves only two successive levels at a time, it can further be compared with the two-level convergence factor. Such comparison is performed in Chapter 3, showing that a nice two-grid convergence (at every level) leads to an optimal McCormick's bound (the best bound from the previous chapter) if and only if a norm of a given projector is bounded on every level.
In Chapter 4 we consider the Fourier analysis setting for scalar PDEs and extend the comparison between two-grid and V-cycle multigrid methods to the smoothing factor. In particular, a two-sided bound involving the smoothing factor is obtained that defines an interval containing both the two-grid and V-cycle convergence rates. This interval is narrow when an additional parameter α is small enough, this latter being a simple function of Fourier components.
Chapter 5 provides a theoretical framework for coarsening by aggregation. An upper bound is presented that relates the two-grid convergence factor with local quantities, each being related to a particular aggregate. The bound is shown to be asymptotically sharp for a large class of elliptic boundary value problems, including problems with anisotropic and discontinuous coefficients.
In Chapter 6 we consider problems resulting from the discretization with edge finite elements of 3D curl-curl equation. The variables in such discretization are associated with edges. We investigate the performance of the Reitzinger and Schöberl algorithm [Num.Lin.Alg.Appl. vol.9(2002), pp.223-238], which uses aggregation techniques to construct the edge prolongation matrix. More precisely, we perform a Fourier analysis of the method in two-grid setting, showing its optimality. The analysis is supplemented with some numerical investigations.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
Balsubramanian, Ravishankar. "Error estimation and grid adaptation for functional outputs using discrete-adjoint sensitivity analysis." Master's thesis, Mississippi State : Mississippi State University, 2002. http://library.msstate.edu/etd/show.asp?etd=etd-10032002-113749.
Full textPattinson, John. "A cut-cell, agglomerated-multigrid accelerated, Cartesian mesh method for compressible and incompressible flow." Pretoria : [s.n.]m, 2006. http://upetd.up.ac.za/thesis/available/etd-07052007-103047.
Full textLao, Kun Leng. "Multigrid algorithm based on cyclic reduction for convection diffusion equations." Thesis, University of Macau, 2010. http://umaclib3.umac.mo/record=b2148274.
Full textHowe, Bill. "Gridfields: Model-Driven Data Transformation in the Physical Sciences." PDXScholar, 2006. https://pdxscholar.library.pdx.edu/open_access_etds/2676.
Full textSampath, Rahul Srinivasan. "A parallel geometric multigrid method for finite elements on octree meshes applied to elastic image registration." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29702.
Full textCommittee Chair: Vuduc, Richard; Committee Member: Biros, George; Committee Member: Davatzikos, Christos; Committee Member: Tannenbaum, Allen; Committee Member: Zhou, Hao Min. Part of the SMARTech Electronic Thesis and Dissertation Collection.
Marquez, Damian Jose Ignacio. "Multilevel acceleration of neutron transport calculations." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19731.
Full textCommittee Chair: Stacey, Weston M.; Committee Co-Chair: de Oliveira, Cassiano R.E.; Committee Member: Hertel, Nolan; Committee Member: van Rooijen, Wilfred F.G.
Ferraz, Paola Cunha 1988. "Implementação de um algoritmo multi-escala para sistemas de equações lineares de grande porte mal condicionados provenientes da discretização de problemas elípticos em dinâmica de fluidos em meios porosos." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/307022.
Full textDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matemática Estatística e Computação Científica
Made available in DSpace on 2018-08-26T22:28:13Z (GMT). No. of bitstreams: 1 Ferraz_PaolaCunha_M.pdf: 6535346 bytes, checksum: 5f9c9ba53cd3e63fc60c09c90ad2c625 (MD5) Previous issue date: 2015
Resumo: O foco deste trabalho é aproximação numérica de problemas envolvendo equações diferenciais parciais (EDPs), de natureza elíptica, no contexto de aplicações em dinâmica de fluidos em meios porosos. Especificamente, a dissertação pretende contribuir com uma implementação de um algoritmo multiescala e multigrid, recentemente introduzido na literatura, para resolução aproximada de sistemas de equações lineares de grande porte e mal condicionados, proveniente dessa classe de EDPs, tipicamente associada a problemas de Poisson de pressão-velocidade com condições de contornos típicas de fluxo em meios porosos. O problema concreto de Poisson discutido neste trabalho será desacoplado do sistema de transporte de EDPs de convecção-difusão, com convecção dominante, e linearizado por meio do emprego de uma técnica de decomposição de operadores. A metodologia para a discretização do problema elíptico de Poisson é elementos finitos mistos híbridos. A resolução numérica do sistema linear resultante deste procedimento será realizado via um método do tipo Gradientes Conjugados com Pré-condicionamento (PCG) multiescala e multigrid. Combinamos as metodologias multi-escala e multigrid de modo a capturar os distintos comprimentos de onda associados aos diferentes comprimentos de onda do operador diferencial auto-adjunto de Poisson, fortemente influenciado pela heterogeneidade das propriedades geológicas do meio poroso, em particular da permeabilidade absoluta, que pode exibir flutuações em várias ordens de grandeza. Experimentos computacionais em aplicações de problemas de dinâmica de fluidos em meios porosos são apresentados e discutidos para verificação dos resultados obtidos
Abstract: The focus of this work is the numerical approximation of differential problems involving partial differential equations (PDE's) of elliptic nature, in the context of modelling and simulation in fluid dynamics in porous media. The dissertation aims to contribute with an implementation of a multiscale multigrid algorithm, recently introduced in the literature, designed for solving ill-conditioned large linear systems of equations derived from those classes of PDE's, typically associated with Poisson problems of pressure-velocity with boundary conditions typical of flow in porous media. The Poisson problem discussed here is identified from the coupled convection-diffusion transport system counterpart of PDE's, with dominated convection, and by a linearization by means the use of an operator splitting approach. The methodology used for the discretization of the Poisson elliptic problem is by mixed hybrid finite elements. The numerical solution of the resulting linear system will be addressed by a multiscale multigrid preconditioned conjugate gradient (PCG) method. We combine both methodologies in order to capture the distinct wavelengths associated with the different wavelengths from the assosiated self-adjoint Poisson operator, strongly influenced by the heterogeneity of the geological properties of the porous media, in particular to the absolute permeability tensor, which in turn might exhibit very large fluctuations of orders of magnitude. Numerical experiments in applications of fluid dynamics problems in porous media are presented and discussed for a verification of the results obtained by direct numerical simulations with the multiscale multigrid algorithm under consideration
Mestrado
Matematica Aplicada
Mestra em Matemática Aplicada
Zhao, Kezhong. "A domain decomposition method for solving electrically large electromagnetic problems." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1189694496.
Full textBöhme, Christian, Anton Holmberg, and Lind Martin Nilsson. "Numerical Analysis of the Two Dimensional Wave Equation : Using Weighted Finite Differences for Homogeneous and Hetrogeneous Media." Thesis, Uppsala universitet, Avdelningen för beräkningsvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-412798.
Full textDai, Ruxin. "Richardson Extrapolation-Based High Accuracy High Efficiency Computation for Partial Differential Equations." UKnowledge, 2014. http://uknowledge.uky.edu/cs_etds/20.
Full textWabro, Markus. "Algebraic multigrid methods for the numerical solution of the incompressible Navier-Stokes equations /." Linz : Trauner, 2003. http://www.gbv.de/dms/goettingen/375396136.pdf.
Full textRittich, Hannah [Verfasser]. "Extending and Automating Fourier Analysis for Multigrid Methods / Hannah Rittich." Wuppertal : Universitätsbibliothek Wuppertal, 2017. http://d-nb.info/1151257028/34.
Full textAshi, Hala. "Numerical methods for stiff systems." Thesis, University of Nottingham, 2008. http://eprints.nottingham.ac.uk/10663/.
Full textSilva, Hugo Marcial Checo. "Models and methods for the direct simulation of rough and micropatterned surfaces." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/55/55134/tde-08072016-165025/.
Full textO atrito em mancais hidrodinâmicos é uma fonte importante de perdas em motores de combustão ([69]). As condições extremas de carga induzem contato entre as superfícies dos mancais. Em tais condições não somente a macro-geometria do mancal é relevante, mas também são as escalas menores da superfície as que determinam o desempenho do mancal. A possibilidade de fabricar superfícies com detalhes na escala do micrometro ([57]) deixou em aberto a questão de se o atrito pode ser reduzido por meio de micro-texturas, até agora com resultados mistos. Este trabalho centra-se no desenvolvimento de métodos numéricos eficientes para resolver problemas de lubrificação na escala da rugosidade das superfícies. Devido às altas velocidades e a forma convergente-divergente dos mancais hidrodinâmicos o fluido cavita. Para tratar o fenômeno de cavitação empregamos o modelo de Elrod-Adams, um modelo conservativo que tem demonstrado em cuidadosos testes numéricos ([12]) e experimentais ([119]) ser essencial para obter resultados físicos significativos. Outro aspecto revelante do modelado é que os efeitos inerciais do mancal são considerados, o que é necessário para simular corretamente texturas em movimento. Como aplicação, os efeitos de micro-texturizar a superfície móvel do mancal foram estudados. Valores realistas são assumidos nos parâmetros físicos que definem o problema. Foram realizados extensivos estudos no regime de lubrificação hidrodinâmica. Também foram executadas simulações convergidas em malha, levando em conta a topografia real de superfícies medidas, e as hipóteses de lubrificação para superfícies rugosas foram avaliadas.
Honková, Michaela. "Numerical Methods of Image Analysis in Astrometry." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-375536.
Full textErtem-Müller, Senem [Verfasser]. "Numerical Efficiency of Implicit and Explicit Methods with Multigrid for Large Eddy Simulation in Complex Geometries / Senem Ertem-Müller." Aachen : Shaker, 2003. http://d-nb.info/1181602696/34.
Full textPiqueras, García Miguel Ángel. "Numerical Methods for Multidisciplinary Free Boundary Problems: Numerical Analysis and Computing." Doctoral thesis, Universitat Politècnica de València, 2018. http://hdl.handle.net/10251/107948.
Full textMany problems in science and engineering are formulated as partial differential equations (PDEs). If the boundary of the domain where these equations are to be solved is not known a priori, we face "Free-boundary problems", which are characteristic of non-time dependent stationary systems; besides, we have "Moving-boundary problems" in temporal evolution processes, where the border changes over time. The solution to these problems is given by the expression of the dependent variable(s) of PDE(s), together with the function that determines the position of the boundary. Since the analytical solution of this type of problems is lacked in most cases, it is necessary to resort to numerical methods that allow an accurate enough solution to be obtained, and which also maintain the qualitative properties of the solution(s) of the continuous model. This work approaches the numerical study of some moving-boundary problems that arise in different disciplines. The applied methodology consists of two successive steps: firstly, the so-called Landau transformation, or "Front-fixing transformation", which is used in the PDE(s) model to maintain the boundary of the domain immobile; later, we proceed to its discretization with a finite difference scheme. Different numerical schemes are obtained and implemented through the MATLAB computational tool. Properties of the scheme and the numerical solution (positivity, stability, consistency, monotonicity, etc.) are studied by an exhaustive numerical analysis. The first chapter of this work reports the state of the art of the field under study, justifies the need to adapt numerical methods to this type of problem, and briefly describes the methodology used in our approach. Chapter 2 presents a problem in Mathematical Biology that consists in determining over time the evolution of an invasive species population that spreads in a habitat. This problem is modelled by a diffusion-reaction equation linked to a Stefan-type condition. The results of the numerical analysis confirm the existence of a spreading-vanishing dichotomy in the long-term evolution of the population density of the invasive species. In particular, it is possible to determine the value of the coefficient of the Stefan condition that separates the propagation behaviour from extinction. Chapters 3 and 4 focus on a problem of Concrete Chemistry with an interest in Civil Engineering: the carbonation of concrete, an evolutionary phenomenon that leads to the progressive degradation of the affected structure and its eventual ruin if preventive measures are not taken. Chapter 3 considers a system of two parabolic type PDEs with two unknowns. For its resolution, the initial and boundary conditions have to be considered together with the Stefan conditions on the carbonation front. The numerical analysis results agree with those obtained in a previous theoretical study. The dynamics of the concentrations and the moving boundary confirm the long-term behaviour of the evolution law for the moving boundary as a "square root of time". Chapter 4 considers a more general model than the previous one, which includes six chemical species, defined in both the carbonated and non-carbonated zones, whose concentrations have to be found. Chapter 5 addresses a heat transfer problem that appears in various industrial processes; in this case, the solidification of metals in casting processes, where the solid phase advances and liquid reduces until it is depleted. The moving boundary (the solidification front) separates both phases. Its position in each instant is the variable to be determined together with the temperature profiles in both phases. After suitable transformation, discretization is carried out to obtain a finite difference scheme to be implemented. The process was subdivided into three temporal stages to deal with the singularities associated with the moving boundary position in the initialisation and depletion stages.
Multitud de problemes en ciència i enginyeria es plantegen com a equacions en derivades parcials (EDPs). Si la frontera del recinte on eixes equacions han de satisfer-se es desconeix a priori, es parla de "Problemas de frontera lliure", propis de sistemes estacionaris no dependents del temps, o bé de "Problemas de frontera mòbil", associats a problemes d'evolució temporal, on la frontera canvia amb el temps. Atés que este tipus de problemes manca en la majoria dels casos de solució analítica coneguda, es fa precís recórrer a mètodes numèrics que permeten obtindre una solució prou aproximada a l'exacta, i que a més mantinga propietats qualitatives de la solució del model continu d'EDP(s). En aquest treball s'ha abordat l'estudi numèric d'alguns problemes de frontera mòbil provinents de diverses disciplines. La metodologia aplicada consta de dos passos successius: en primer lloc, s'aplica l'anomenada transformació de Landau o "Front-fixing transformation" al model en EDP(s) a fi de mantindre immòbil la frontera del domini; posteriorment, es procedix a la seva discretització a través d'un esquema en diferències finites. D'ací s'obtenen esquemes numèrics que s'implementen per mitjà de la ferramenta informàtica MATLAB. Per mitjà d'una exhaustiva anàlisi numèrica, s'estudien propietats de l'esquema i de la solució numèrica (positivitat, estabilitat, consistència, monotonia, etc.). En el primer capítol d'aquest treball es revisa l'estat de l'art del camp objecte d'estudi, es justifica la necessitat de disposar de mètodes numèrics adaptats a aquest tipus de problemes i es descriu breument la metodologia emprada en el nostre enfocament. El Capítol 2 es dedica a un problema pertanyent a la Biologia Matemàtica i que consistix a determinar l'evolució en el temps de la distribució de la població d'una espècie invasora que es propaga en un hàbitat. Este model consistix en una equació de difusió-reacció unida a una condició tipus Stefan, que relaciona les funcions solució i frontera mòbil a determinar. Els resultats de l'anàlisi numèrica confirmen l'existència d'una dicotomia propagació-extinció en l'evolució a llarg termini de la densitat de població de l'espècie invasora. En particular, s'ha pogut precisar el valor del coeficient de la condició de Stefan que separa el comportament de propagació del d'extinció. Els Capítols 3 i 4 se centren en un problema de Química del Formigó amb interés en Enginyeria Civil: el procés de carbonatació del formigó, fenomen evolutiu que comporta la degradació progressiva de l'estructura afectada i finalment la seua ruïna, si no es prenen mesures preventives. En el Capítol 3 es considera un sistema de dos EDPs de tipus parabòlic amb dos incògnites. Per a la seua resolució, cal considerar a més, les condicions inicials, les de contorn i les de tipus Stefan en la frontera. Els resultats de l'anàlisi numèrica s'ajusten als obtinguts en un estudi teòric previ. S'han dut a terme experiments numèrics, comprovant la tendència de la llei d'evolució de la frontera mòbil cap a una funció del tipus "arrel quadrada del temps". En el Capítol 4 es considera un model més general, en el que intervenen sis espècies químiques les concentracions de les quals cal trobar, i que es troben tant en la zona carbonatada com en la no carbonatada. En el Capítol 5 s'aborda un problema de transmissió de calor que apareix en diversos processos industrials; en aquest cas, en el refredament durant la bugada de metall fos, on la fase sòlida avança i la líquida es va extingint. La frontera mòbil (front de solidificació) separa ambdues fases, sent la seua posició en cada instant la variable a determinar, junt amb les temperatures en cada una de les dos fases. Després de l'adequada transformació i discretització, s'implementa un esquema en diferències finites, subdividint el procés en tres estadis temporals, per tal de tractar les singularitats asso
Piqueras García, MÁ. (2018). Numerical Methods for Multidisciplinary Free Boundary Problems: Numerical Analysis and Computing [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/107948
TESIS
Fu, Qi. "Numerical methods for pricing callable bonds." Thesis, University of Macau, 2011. http://umaclib3.umac.mo/record=b2493162.
Full textZahedi, Sara. "Numerical Methods for Fluid Interface Problems." Doctoral thesis, KTH, Numerisk analys, NA, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-33111.
Full textQC 20110503
Frankcombe, Terry James. "Numerical methods in reaction rate theory /." [St. Lucia, Qld.], 2002. http://adt.library.uq.edu.au/public/adt-QU20021128.175205/index.html.
Full textHarb, Ammar. "Discrete Stability of DPG Methods." PDXScholar, 2016. http://pdxscholar.library.pdx.edu/open_access_etds/2916.
Full textIguti, F. "On some numerical methods in nonlinear structural analysis." Thesis, Imperial College London, 1985. http://hdl.handle.net/10044/1/37732.
Full textYoutsos, Michael Spiro. "Numerical analysis of thermal enhanced oil recovery methods." Thesis, University of Cambridge, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648536.
Full textLiu, Dong Dong. "Analysis of numerical methods for some tensor equations." Thesis, University of Macau, 2018. http://umaclib3.umac.mo/record=b3952476.
Full textBray, Kasey. "On the Role of Ill-conditioning: Biharmonic Eigenvalue Problem and Multigrid Algorithms." UKnowledge, 2019. https://uknowledge.uky.edu/math_etds/62.
Full textFong, Wai Lam. "Numerical methods for classification and image restoration." HKBU Institutional Repository, 2013. http://repository.hkbu.edu.hk/etd_ra/1488.
Full textMaclean, John. "Numerical multiscale methods for ordinary differential equations." Thesis, The University of Sydney, 2014. http://hdl.handle.net/2123/12818.
Full textOu, Rongfu. "Parallel numerical integration methods for nonlinear dynamics." Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/18181.
Full textLee, Kai Yan. "Heating the Early Universe : Numerical Methods and Their Analysis." Doctoral thesis, Stockholms universitet, Institutionen för astronomi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-130436.
Full textAt the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Submitted. Paper 3: Submitted.
Eu, Christina Nguk Ling. "Numerical Analysis in Nonlinear Least Squares Methods and Applications." Thesis, Curtin University, 2017. http://hdl.handle.net/20.500.11937/70491.
Full textMazzotti, Matteo <1984>. "Numerical methods for the dispersion analysis of Guided Waves." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5951/1/Mazzotti_Matteo_tesi.pdf.
Full textMazzotti, Matteo <1984>. "Numerical methods for the dispersion analysis of Guided Waves." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5951/.
Full textAghabarati, Ali. "Multilevel and algebraic multigrid methods for the higher order finite element analysis of time harmonic Maxwell's equations." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=121485.
Full textLa méthode des éléments finis (FEM) appliquée à la dispersion des ondes et aux problèmes de champ de vecteurs quasi-statique dans le domaine fréquentiel mène à des systèmes d'équations linéaires rares, symétriques-complexes. Pour de grands problèmes ayant des géométries complexes, la plupart du temps et de la mémoire d'ordinateur utilisé par FEM va à la résolution de l'équation de la matrice. Les méthodes itératives de Krylov sont celles largement utilisées dans la résolution de grands systèmes creux. Elles dépendent fortement des préconditionnement qui accélèrent la convergence. Toutefois, l'application de préconditionnements conventionnels à l'opérateur "rot-rot" qui surgit en électromagnétisme vectoriel n'aboutit pas à des résultats satisfaisants et des techniques de préconditionnement spécialisés sont exigées.Cette thèse présente des techniques de préconditionnement efficaces multiniveau et multigrilles algébrique (AMG) pour l'analyse p-adaptative FEM. Dans la p-adaptation, des éléments finis de différents ordres polynomiaux sont présents dans le maillage et la matrice du système peut être structurée en blocs correspondant aux ordres des fonctions de base. Les nouveaux préconditionneurs sont basés sur un type d'inversion approximative à multiniveau p Schwarz (pMUS) du système structuré de bloc. Une correction à niveaux multiples en cycle V débute par l'application de Gauss-Seidel au niveau du bloc le plus élevé, suivi par le niveau inférieur, et ainsi de suite. De l'autre côté du V, des itérations de Gauss-Seidel sont appliquées en ordre inverse. Au bas du cycle se trouve le système d'ordre le plus bas, qui est habituellement résolu exactement avec un solveur direct. L'alternative proposée est d'utiliser l'espace auxiliaire de préconditionnement (ASP) au niveau le plus bas et de poursuivre le cycle en V vers le bas, d'abord en un ensemble d'auxiliaires, basé sur les espacements de nœuds, à travers une série de plus en plus petites de matrices générées par un multigrille algébrique (AMG). L'approche de grossissement algébrique est particulièrement utile aux problèmes ayant de fins détails géométriques, nécessitant une très grande maille dans laquelle la majeure partie des éléments restent à un niveau plus bas.En outre, pour des problèmes d'onde, la technique "décalé Laplace" est appliquée, dans laquelle une partie de l'algorithme ASP/AMG utilise une fréquence complexe perturbée. Une accélération de la convergence significative est atteinte. La performance des algorithmes de Krylov est davantage renforcée au cours du p-adaptation par l'incorporation d'une technique de déflation. Cette saillie fait dépasser hors du système préconditionné, les vecteurs propres correspondants aux plus petites valeurs propres. La construction du sous-espace de déflation est basée sur une estimation efficace des vecteurs propres à partir d'informations obtenues lors de la résolution du premier problème dans une séquence p-adaptatif. Des expériences numériques approfondies ont été effectuées et les résultats sont présentés à la fois aux problèmes d'onde et quasi-statiques. Les cas de test sont considérés comme compliqués à résoudre et les résultats numériques montrent la robustesse et l'efficacité des nouveaux préconditionnements. Les méthodes de Krylov de déflation préconditionnés par l'approche multiniveaux/ASP/AMG actuelle sont toujours considérablement plus rapides que les méthodes de référence et des accélérations allant jusqu'à 10 sont atteintes pour certains problèmes de test.
Bayliss, Martin. "The numerical modelling of elastomers." Thesis, Cranfield University, 2003. http://hdl.handle.net/1826/87.
Full textRasmussen, Bryan Michael. "Numerical Methods for the Continuation of Invariant Tori." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/5273.
Full textZhang, Zan. "Numerial development of an improved element-free Galerkin method for engineering analysis /." access full-text access abstract and table of contents, 2009. http://libweb.cityu.edu.hk/cgi-bin/ezdb/thesis.pl?phd-bc-b23750613f.pdf.
Full text"Submitted to the Department of Building and Construction in partial fulfillment of the requirements for the degree of Doctor of Philosophy." Includes bibliographical references (leaves [170]-184)
Li, Song. "Numerical methods for stable inversion of nonlinear systems." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/15028.
Full textHuang, Ning Ying. "Numerical methods for early-exercise option pricing via Fourier analysis." Thesis, University of Macau, 2010. http://umaclib3.umac.mo/record=b2148270.
Full text