Dissertations / Theses: 'Metodo parallelo'

1

Synn, Sang-Youp. "Practical domain decomposition approaches for parallel finite element analysis." Diss., Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/17032.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Su, (Philip) Shin-Chen. "Parallel subdomain method for massively parallel computers." Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/17376.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Pippig, Michael. "Massively Parallel, Fast Fourier Transforms and Particle-Mesh Methods: Massiv parallele schnelle Fourier-Transformationen und Teilchen-Gitter-Methoden." Doctoral thesis, Universitätsverlag der Technischen Universität Chemnitz, 2015. https://monarch.qucosa.de/id/qucosa%3A20398.

Full text

Abstract:

The present thesis provides a modularized view on the structure of fast numerical methods for computing Coulomb interactions between charged particles in three-dimensional space. Thereby, the common structure is given in terms of three self-contained algorithmic frameworks that are built on top of each other, namely fast Fourier transform (FFT), nonequispaced fast Fourier transform (NFFT) and NFFT based particle-mesh methods (P²NFFT). For each of these frameworks algorithmic enhancement and parallel implementations are presented with special emphasis on scalability up to hundreds of thousands of parallel processes. In the context of FFT massively parallel algorithms are composed from hardware adaptive low level modules provided by the FFTW software library. The new algorithmic NFFT concepts include pruned NFFT, interlacing, analytic differentiation, and optimized deconvolution in Fourier space with respect to a mean square aliasing error. Enabled by these generalized concepts it is shown that NFFT provides a unified access to particle-mesh methods. Especially, mixed-periodic boundary conditions are handled in a consistent way and interlacing can be incorporated more efficiently. Heuristic approaches for parameter tuning are presented on the basis of thorough error estimates.
Die vorliegende Dissertation beschreibt einen modularisierten Blick auf die Struktur schneller numerischer Methoden für die Berechnung der Coulomb-Wechselwirkungen zwischen Ladungen im dreidimensionalen Raum. Die gemeinsame Struktur ist geprägt durch drei selbstständige und auf einander aufbauenden Algorithmen, nämlich der schnellen Fourier-Transformation (FFT), der nicht äquidistanten schnellen Fourier-Transformation (NFFT) und der NFFT-basierten Teilchen-Gitter-Methode (P²NFFT). Für jeden dieser Algorithmen werden Verbesserungen und parallele Implementierungen vorgestellt mit besonderem Augenmerk auf massiv paralleler Skalierbarkeit. Im Kontext der FFT werden parallele Algorithmen aus den Hardware adaptiven Modulen der FFTW Softwarebibliothek zusammengesetzt. Die neuen NFFT-Konzepte beinhalten abgeschnittene NFFT, Versatz, analytische Differentiation und optimierte Entfaltung im Fourier-Raum bezüglich des mittleren quadratischen Aliasfehlers. Mit Hilfe dieser Verallgemeinerungen bietet die NFFT einen vereinheitlichten Zugang zu Teilchen-Gitter-Methoden. Insbesondere gemischt periodische Randbedingungen werden einheitlich behandelt und Versatz wird effizienter umgesetzt. Heuristiken für die Parameterwahl werden auf Basis sorgfältiger Fehlerabschätzungen angegeben.

APA, Harvard, Vancouver, ISO, and other styles

4

Baladron, Pezoa Javier. "Exploring the neural codes using parallel hardware." Phd thesis, Université Nice Sophia Antipolis, 2013. http://tel.archives-ouvertes.fr/tel-00847333.

Full text

Abstract:

The aim of this thesis is to understand the dynamics of large interconnected populations of neurons. The method we use to reach this objective is a mixture of mesoscopic modeling and high performance computing. The rst allows us to reduce the complexity of the network and the second to perform large scale simulations. In the rst part of this thesis a new mean eld approach for conductance based neurons is used to study numerically the eects of noise on extremely large ensembles of neurons. Also, the same approach is used to create a model of one hypercolumn from the primary visual cortex where the basic computational units are large populations of neurons instead of simple cells. All of these simulations are done by solving a set of partial dierential equations that describe the evolution of the probability density function of the network. In the second part of this thesis a numerical study of two neural eld models of the primary visual cortex is presented. The main focus in both cases is to determine how edge selection and continuation can be computed in the primary visual cortex. The dierence between the two models is in how they represent the orientation preference of neurons, in one this is a feature of the equations and the connectivity depends on it, while in the other there is an underlying map which denes an input function. All the simulations are performed on a Graphic Processing Unit cluster. Thethesis proposes a set of techniques to simulate the models fast enough on this kind of hardware. The speedup obtained is equivalent to that of a huge standard cluster.

APA, Harvard, Vancouver, ISO, and other styles

5

Ademoyero, Oreoluwa Oyinlade. "A parallel Galerkin boundary element method." Thesis, University of Hertfordshire, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.410144.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Jackson, Benjamin Grant. "Parallel methods for short read assembly." [Ames, Iowa : Iowa State University], 2009.

Find full text

APA, Harvard, Vancouver, ISO, and other styles

7

Kazemi, Noj. "Circuit analysis of a parallel plate waveguide." Thesis, KTH, Elektroteknisk teori och konstruktion, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-222617.

Full text

Abstract:

The aim of this work was to model a four-port waveguide as a simple circuit,by first starting with a two-port then a three-port waveguide. Duethat the work was based on Nathan Marcuvitz book Waveguide handbook,an analytical solution for the circuit parameters was desired. In order toobtain an analytical solution three methods were studied; the Variationalmethod, the Integral equation method and the Static method. Out of thesethree methods the latter was chosen, because its strength of simplifying theboundary conditions. The goal to model a four-port and a three-portedwaveguide was too complicated. This led to that the goal was changed totrying to get a higher accuracy on the existing circuit model for a two-portwaveguide, by solving an extension to the circuit parameter. This was donebecause Marcuvitz only treated the first two modes correctly and it was notclear if the circuit model was stable for the higher orders of Taylor series. Inthe end a circuit model for a waveguide with an iris that treats the first 16modes correctly was solved. By looking at the dispersive properties of thecircuit a comparison with simulation software CST Microwave Studio couldbe done, which resulted in that the circuit model gave good results up to2b/ < 1. It was also showed that the accuracy was about the same as thecircuit model found in Waveguide handbook, but it can be mentioned thatthe accuracy is minimally better for the circuit model that was developed inthis work. Something that was discovered in this work is that the restrictionmentioned in Waveguide handbook for the case when the window is centeredis unreliable, it should be 2b/ < 1. It also appeared that the circuit modelremained stable for higher orders of the Taylor series, in this case up to the16:th order.
M°alet med detta arbete var att modellera en fyr-portars v°agledare somen simpel elektrisk krets, genom att f¨orst b¨orja med en tv°a-portars sedantre-portars -v°agledare. Detta arbete var baserat p°a Nathan Marcuvitz bokWaveguide handbook, d¨arav s¨oktes det en analytisk l¨osning f¨or kretsparametrarna.F¨or att kunna f°a en analytisk l¨osning, studerades tre metoder;Variationsmetoden, Integralsekvationsmetoden samt den Statiskametoden.Av dessa tre metoder valdes den sistn¨amnda, p°a grund av dess styrka medatt f¨orenkla randvillkoren. M°alet att modellera en fyr-portars samt en treportarsv°agledare var alldeles f¨or komplicerat. Detta ledde till att m°alet¨andrades till att f¨ors¨oka f°a en h¨ogre precision p°a den befintliga kretsmodellenf¨or en tv°a portars v°agledare, genom att l¨osa ut flera termer till kretsparametern.Detta gjordes d°a Marcuvitz endast hanterade de tv°a f¨orstamoderna korrekt, samt att det inte framgick ifall kretsmodellen ¨ar stabil f¨orh¨ogre ordningar av Taylor serier. I slut¨andan l¨ostes en kretsmodel f¨or env°agledare med en iris som hanterar de f¨orsta 16 moderna korrekt. Genomatt kolla p°a de dispersiva egenskaperna f¨or kretsen, kunde en j¨amf¨orelse medsimuleringsprogrammet CST Microwave Studio ske, d¨ar slutsatsen blev attkretsmodellen gav goda resultat upp till 2b/ < 1. Det visade ¨aven sig attprecisionen var ungef¨ar densamma som den kretsmodell som°aterfinns i Waveguidehandbook, men det kan n¨amnas att precisionen ¨ar minimalt b¨attref¨or den kretsmodell som togs fram i detta arbete. En sak som uppt¨acktes underdetta arbete var att restriktionen som n¨amns i Waveguide handbook f¨orfallet n¨ar gapet f¨or irisen ¨ar centrerad st¨ammer inte, den b¨or vara 2b/ < 1.Dessutom visade det sig att kretsmodellen fortfarande var stabil f¨or h¨ogreordningar av Taylorserier, i detta fall upp till den 16:e ordningen.

APA, Harvard, Vancouver, ISO, and other styles

8

Driver, Maria Sosonkina Jr. "Parallel Sparse Linear Algebra for Homotopy Methods." Diss., Virginia Tech, 1997. http://hdl.handle.net/10919/30718.

Full text

Abstract:

Globally convergent homotopy methods are used to solve difficult nonlinear systems of equations by tracking the zero curve of a homotopy map. Homotopy curve tracking involves solving a sequence of linear systems, which often vary greatly in difficulty. In this research, a popular iterative solution tool, GMRES(k), is adapted to deal with the sequence of such systems. The proposed adaptive strategy of GMRES(k) allows tuning of the restart parameter k based on the GMRES convergence rate for the given problem. Adaptive GMRES(k) is shown to be superior to several other iterative techniques on analog circuit simulation problems and on postbuckling structural analysis problems. Developing parallel techniques for robust but expensive sequential computations, such as globally convergent homotopy methods, is important. The design of these techniques encompasses the functionality of the iterative method (adaptive GMRES(k)) implemented sequentially and is based on the results of a parallel performance analysis of several implementations. An implementation of adaptive GMRES(k) with Householder reflections in its orthogonalization phase is developed. It is shown that the efficiency of linear system solution by the adaptive GMRES(k) algorithm depends on the change in problem difficulty when the problem is scaled. In contrast, a standard GMRES(k) implementation using Householder reflections maintains a constant efficiency with increase in problem size and number of processors, as concluded analytically and experimentally. The supporting numerical results are obtained on three distributed memory homogeneous parallel architectures: CRAY T3E, Intel Paragon, and IBM SP2.
Ph. D.

APA, Harvard, Vancouver, ISO, and other styles

9

Lecomber, David. "Methods of BSP programming." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299799.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Müller, Björn. "Parallel Finite Element Method with FEAP 8.2." Darmstadt TU, Fachgebiet Numerische Berechnungsverfahren im Maschinenbau, 2009. http://tuprints.ulb.tu-darmstadt.de/1336/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Ou, Rongfu. "Parallel numerical integration methods for nonlinear dynamics." Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/18181.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Wood, Kenneth Robert. "Parallel logic simulation and applied formal methods." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315774.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Potgieter, Andrew. "A Parallel Multidimensional Weighted Histogram Analysis Method." Thesis, University of Cape Town, 2014. http://pubs.cs.uct.ac.za/archive/00000986/.

Full text

Abstract:

The Weighted Histogram Analysis Method (WHAM) is a technique used to calculate free energy from molecular simulation data. WHAM recombines biased distributions of samples from multiple Umbrella Sampling simulations to yield an estimate of the global unbiased distribution. The WHAM algorithm iterates two coupled, non-linear, equations, until convergence at an acceptable level of accuracy. The equations have quadratic time complexity for a single reaction coordinate. However, this increases exponentially with the number of reaction coordinates under investigation, which makes multidimensional WHAM a computationally expensive procedure. There is potential to use general purpose graphics processing units (GPGPU) to accelerate the execution of the algorithm. Here we develop and evaluate a multidimensional GPGPU WHAM implementation to investigate the potential speed-up attained over its CPU counterpart. In addition, to avoid the cost of multiple Molecular Dynamics simulations and for validation of the implementations we develop a test system to generate samples analogous to Umbrella Sampling simulations. We observe a maximum problem size dependent speed-up of approximately 19 for the GPGPU optimized WHAM implementation over our single threaded CPU optimized version. We find that the WHAM algorithm is amenable to GPU acceleration, which provides the means to study ever more complex molecular systems in reduced time periods.

APA, Harvard, Vancouver, ISO, and other styles

14

Klene, Michael. "Parallel implementation of the MC-SCF method." Thesis, King's College London (University of London), 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.397278.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Davidson, David Bruce. "Parallel algorithms for electromagnetic moment method formulations." Thesis, Stellenbosch : Stellenbosch University, 1991. http://hdl.handle.net/10019.1/69369.

Full text

Abstract:

Thesis (PhD) -- Stellenbosch University, 1991.
ENGLISH ABSTRACT: This dissertation investigates the moment method solution of electromagnetic radiation and scattering problems using parallel computers. In particular, electromagnetically large problems with arbitrary geometries are considered. Such problems require a large number of unknowns to obtain adequate approximate solutions, and make great computational demands. This dissertation considers in detail the efficient exploitation of the potential offered by parallel computers for solving such problems, and in particular the class of local memory Multiple Instruction, Multiple Data systems. A brief history of parallel computing is presented. Methods for quantifying the efficiency of parallel algorithms are reviewed. The use of pseudo-code for documenting algorithms is discussed and a pseudo-code notation is defined that is used in later chapters. A new parallel conjugate gradient algorithm, suitable for the solution of general systems of linear equations with complex values, is presented. A method is described to handle efficiently the Hermitian transpose of the matrix required by the algorithm. Careful attention is paid to the theoretical analysis of the algorithm's parallel properties (in particular, speed-up and efficiency). Pseudo-code is presented for the algorithms. Timing results for a moment method code, running on a transputer array and using this conjugate gradient solver, are presented and compared to the theoretical predictions. A parallel LU algorithm is described and documented in pseudo-code. A new graphical description of the algorithm is presented that simplifies the identification of the parallelism and the analysis of the algorithm. The use of formal methods for extracting parallelism via the use of invariants is presented and new examples given. The speed-up and efficiency of the algorithm are analyzed theoretically, using new methods that are simpler than those described in the literature. Techniques for optimizing the efficiency of parallel algorithms are introduced, and illustrated with pseudo-code. New parallel forward and backward substitution algorithms using the data distribution required for the parallel LV algorithm are described, and documented with pseudo-code. Results obtained with a Occam 2 moment method code running on a transputer array using these parallel LU solver and substitution algorithms are presented and compared with the theoretical predictions. PARNEC, a new Occam 2 implementation of the thin-wire core of NEC2, is discussed. The basic 'theory of NEC2 is reviewed. Problems with early attempts at combining Occam and FORTRAN are reported. Methodologies for re-coding an old code written in an unstructured language in a. modern structured language are discussed. Methods of parallelizing the matrix generation are discussed. The accuracy of large moment method formulations is investigated, as is the effect of machine precision on the solutions. The use of the biconjugate gradient method to accelerate convergence is briefly considered and rejected. The increased size of problem that can be handled by PARNEC, running on a transputer array, is demonstrated. Conclusions are dra.wn regarding the contributions of this dissertation to the development of efficient parallel electromagnetic moment method algorithms.
AFRIKAANSE OPSOMMING: Hierdie proefskrif ondersoek die momentmetode oplossing van elektromagnetiese straling- en strooiingprobleme d.m.v. multiverwerkers. In besonder, elektromagneties groot probleme met arbitrere geometriee word beskou. Sulke probleme vereis 'n groot aantal onbekendes om 'n voldoende benaderde oplossing te kry, en stel groot berekenings vereistes. Hierdie proefskrif beskou in detail die doeltreffende benutting van die potensiaal wat multiverwerkers vir sulke problem hied, in besonder die klas van lokale geheue Veelvoudige Instruksie, Veelvoudige Data stelsels. 'n Kort geskiedenis van multiverwerkers word gegee. Metodes vir die kwantifisering van die effektiwiteit van multiverwerkers word hersien. Die . gebruik van pseudokode vir die dokumentering van algoritmes word bespreek en 'n pseudokode notasie word gedefinieer wat gebruik word in latere hoofstukke. 'n Nuwe parallelle toegevoegde helling-algoritme wat geskik is vir die oplossing van algemene stelsels van lineere vergelykings word aangebied. 'n Metode word beskryf om op 'n doeltreffende wyse die Hermitiese transponent van die matriks, wat deur die algoritme benodig word, te hanteer. Sorgvuldige aandag word aan die teoretiese analise van die paralleleienskappe van die algoritme gegee (in die besonder, versnelling en doeltreffendheid). Pseudokode word aangebied vir die algoritmes. Resultate vir die looptyd van 'n momentmetode program, wat op 'n transputerskikking loop, word gegee en vergelyk met die teoretiese voorspellings. 'n Parallelle L U algoritme word beskryf en gedokumenteer in pseudokode. 'n Nuwe grafiese beskrywing van die algoritme, wat die identifikasie van parallelisme en die analise van die algoritme vergemaklik, word gegee. Die gebruik van formele metodes vir die onttrekking van parallelisme d.m.v. invariante word getoon en nuwe voorbeelde word gegee. Die versnelling en doeltreffendheid van die algoritme word teoreties geanaliseer, d.m.v. nuwe metodes wat eenvoudiger is as die wat in die literatuur beskryf word. Tegnieke vir die optimering van die doeltreffendheid van parallelle algoritmes word ingevoer, en gelllustreer met pseudokode. Nuwe parallelle voor- en truwaarts-substitusie algoritmes wat die data verspreiding van die parallelle LU algoritme gebruik word beskryf, en gedokumenteer met pseudokode. Resultate verkry met 'n Occam 2 momentmetode program wat op 'n transputerskikking loop en die parallelle L U en substit'usie algoritmes gebruik, word gegee en vergelyk met teoretiese voorspellings. PARNEC, 'n nuwe Occam 2 implementering van die dun-draad kern van NEC2, word bespreek. Die basiese teorie van NEC2 word opgesom. Verslag word gedoen oor probleme met vroee pogings orh Occam en FORTRAN te kombineer. Metodes om 'n ou program, geskryf in 'n ongestruktureerde taal, in 'n moderne gestruktureerde taal te herskryf word bespreek. Metodes om die matriksopwekking te paralleliseer word bespreek. Die akkuraatheid van groot momentmetode formulerings word ondersoek, asook die effek van masjienpresisie op die oplossings. Die gebruik van die dubbeltoegevoegde helling-metode om konvergensie te versnel word kortliks beskou en verwerp. Die vergrote probleemgrootte, wat met PARNEC op- 'n transputerskikking uitgevoer kan word, word gedemonstreer. Gevolgtrekkings word gemaak rakende die bydraes van hierdie proefskrif tot die ontwikkeling van doeltreffende parallelle elektromagnetiese momentmetode algoritmes.

APA, Harvard, Vancouver, ISO, and other styles

16

Tofts, Chris. "Proof methods and pragmatics for parallel programming." Thesis, University of Edinburgh, 1990. http://hdl.handle.net/1842/14544.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Wu, Fei. "Parallel computational methods for constrained mechanical systems." Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/282561.

Full text

Abstract:

Two methods suitable for parallel computation in the study of mechanical systems with holonomic and nonholonomic constraints are presented: one is an explicit solution based on generalized inverse algebra; the second solves problems of this class through the direct application of Gauss' principle of least constraint and genetic algorithms. Algorithms for both methods are presented for sequential and parallel implementations. The method using generalized inverses is able to solve problems that involve redundant, degenerate and intermittent constraints, and can identify inconsistent constraint sets. It also allows a single program to perform pure kinematic and dynamic analyses. Its computational cost is among the lowest in comparison with other methods. In addition, constraint violation control methods are investigated to improve integration accuracy and further reduce computational cost. Constrained dynamics problems are also solved using optimization methods by applying Gauss' principle directly. An objective function that incorporates constraints is derived using a symmetric scheme, which is implemented using genetic algorithms in a parallel computing environment. It is shown that this method is capable of solving the same cases of constraints as the former method. Examples and numerical experiments demonstrating the applications of the two methods to constrained multiparticle and multibody systems are presented.

APA, Harvard, Vancouver, ISO, and other styles

18

Coomer, Rob. "Parallel iterative methods in semiconductor device modelling." Thesis, University of Bath, 1994. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359852.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Linardakis, Leonidas. "A Parallel Two Dimensional Delaunay Decoupling Method." W&M ScholarWorks, 2003. https://scholarworks.wm.edu/etd/1539626828.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Johnson, Anne. "Parallelising implicit methods on unstructured grids." Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320231.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Sellami, Hatem. "Parallel simulation of marked graphs." Diss., Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/13045.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Chen, Y. "Formal methods for global synchrony." Thesis, University of Oxford, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365295.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Kopek, Christopher Vincent. "Parallel intrusion detection systems for high speed networks using the divided data parallel method." Electronic thesis, 2007. http://dspace.zsr.wfu.edu/jspui/handle/10339/191.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Chuang, Shih-Chang. "Parallel methods for high-performance finite element methods based on sparsity." Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/18177.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Pieskä, J. (Jali). "Domain decomposition methods for continuous casting problem." Doctoral thesis, University of Oulu, 2004. http://urn.fi/urn:isbn:9514274679.

Full text

Abstract:

Abstract Several numerical methods and algorithms, for solving the mathematical model of a continuous casting process, are presented, and theoretically studied, in this work. The numerical algorithms can be divided in to three different groups: the Schwarz type overlapping methods, the nonoverlapping Splitting iterative methods, and the Predictor-Corrector type nonoverlapping methods. These algorithms are all so-called parallel algorithms i.e., they are highly suitable for parallel computers. Multiplicative, additive Schwarz alternating method and two asynchronous domain decomposition methods, which appear to be a two-stage Schwarz alternating algorithms, are theoretically and numerically studied. Unique solvability of the fully implicit and semi-implicit finite difference schemes as well as monotone dependence of the solution on the right-hand side are proved. Geometric rate of convergence for the iterative methods is investigated. Splitting iterative methods for the sum of maximal monotone and single-valued monotone operators in a finite-dimensional space are studied. Convergence, rate of convergence and optimal iterative parameters are derived. A two-stage iterative method with inner iterations is analyzed in the case when both operators are linear, self-adjoint and positive definite. Several new finite-difference schemes for a nonlinear convection-diffusion problem are constructed and numerically studied. These schemes are constructed on the basis of non-overlapping domain decomposition and predictor-corrector approach. Different non-overlapping decompositions of a domain, with cross-points and angles, schemes with grid refinement in time in some subdomains, are used. All proposed algorithms are extensively numerically tested and are founded stable and accurate under natural assumptions for time and space grid steps. The advantages and disadvantages of the numerical methods are clearly seen in the numerical examples. All of the algorithms presented are quite easy and straight forward, from an implementation point of view. The speedups show that splitting iterative method can be parallelized better than multiplicative or additive Schwarz alternating method. The numerical examples show that the multidecomposition method is a very effective numerical method for solving the continuous casting problem. The idea of dividing the subdomains to smaller subdomains seems to be very beneficial and profitable. The advantages of multidecomposition methods over other methods is obvious. Multidecomposition methods are extremely quick, while being just as accurate as other methods. The numerical results for one processor seem to be very promising.

APA, Harvard, Vancouver, ISO, and other styles

26

Ibraev, Suiunbek. "A new parallel method for verified global optimization." [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=963452304.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Fleissner, Florian. "Parallel object oriented simulation with Lagrangian particle methods." Aachen Shaker, 2009. http://d-nb.info/1000976742/04.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Saltvik, Ingar. "Parallel Methods for Real-Time Visualization of Snow." Thesis, Norwegian University of Science and Technology, Department of Computer and Information Science, 2006. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-10097.

Full text

Abstract:

Using computer generated imaging is becoming more and more popular in areas such as computer gaming, movie industry and simulation. A familiar scene in the winter months for most us in the Nordic countries is snow. This thesis discusses some of the complex numerical algorithms behind snow simulations. Previous methods for snow simulation have either covered only a very limited aspect of snow, or have been unsuitable for real-time performance. In this thesis, some of these methods are combined into a model for real-time snow simulation that handles both snowflake motion through the air, wind simulation, and accumulation of snow on objects and the ground. With a goal towards achieving real-time performance with more than 25 frames per second, some new parallel methods for the snow model are introduced. Focus is set on efficient parallelization on new SMP and multi-core computer systems. The algorithms are first parallelized in a pure data-parallel manner by dividing the data structures among threads. This scheme is then improved by overlapping inherently sequential algorithms with computations for the following frame, to eliminate processor idle time. A speedup of 1.9 on modern dual CPU workstations is achieved, while displaying a visually satisfying result in real-time. By utilizing Hyper-Threading enabled dual CPU systems, the speedup is further improved to 2.0.

APA, Harvard, Vancouver, ISO, and other styles

29

Chelliah, Joel Eelaraj. "Parallel Methods for Projection on Strongly Curved Surfaces." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for datateknikk og informasjonsvitenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-14979.

Full text

Abstract:

Using the parallel architecture of the graphics processing unit for general purpose programming has become increasingly common in the recent years. The process of creating a mathematically correct transformation of a scene for curved stereoscopic projection is a very expensive task, which would greatly benefit from a massively parallel solution implemented on the GPU.In this thesis, we first investigate two different methods for obtaining a mathematically correct transformation of images intended for stereoscopic projection on strongly curved surfaces. One method revolves around transforming a pre-rendered image, pixel by pixel, while the other method applies the transformation to the projection of the vertices in the scene before they are rendered as an image. We then develop massively parallel solutions for both these methods on the GPU, striving to a reach a real-time rate for the stereoscopic projection of the transformed images.We test both methods for different problem areas, and compare the results to map their strengths and weaknesses. From the obtained results, we conclude that they are both useful in different areas. The vertex transformation performs poorly when the number of vertices in the scene is very high, but for a moderate number of vertices it achieves excellent results, even for exceptionally large image resolutions. The pixel transformation is far less affected by the number of vertices in the scene; however its performance declines rapidly as we increase the size of the image. Both methods were able to execute in real-time for relevant problem sizes.

APA, Harvard, Vancouver, ISO, and other styles

30

Mehdi, Malika. "PARALLEL HYBRID OPTIMIZATION METHODS FOR PERMUTATION BASED PROBLEMS." Phd thesis, Université des Sciences et Technologie de Lille - Lille I, 2011. http://tel.archives-ouvertes.fr/tel-00841962.

Full text

Abstract:

La résolution efficace de problèmes d'optimisation a permutation de grande taille nécessite le développement de méthodes hybrides complexes combinant différentes classes d'algorithmes d'optimisation. L'hybridation des metaheuristiques avec les méthodes exactes arborescentes, tel que l'algorithme du branch-and-bound (B&B), engendre une nouvelle classe d'algorithmes plus efficace que ces deux classes de méthodes utilisées séparément. Le défi principal dans le développement de telles méthodes consiste a trouver des liens ou connections entre les stratégies de recherches divergentes utilisées dans les deux classes de méthodes. Les Algorithmes Genetiques (AGs) sont des metaheuristiques, a base de population, tr'es populaires bas'es sur des op'erateurs stochastiques inspirés de la théorie de l'évolution. Contrairement aux AGs et aux m'etaheuristiques généralement, les algorithmes de B&B sont basées sur l'énumération implicite de l'espace de recherche représente par le moyen d'un arbre, dit arbre de recherche. Notre approche d'hybridation consiste a définir un codage commun des solutions et de l'espace de recherche ainsi que des opérateurs de recherche ad'equats afin de permettre un couplage efficace de bas niveau entre les deux classes de méthodes AGs et B&B. La représentation de l'espace de recherche par le moyen d'arbres est traditionnellement utilis'ee dans les algorithmes de B&B. Dans cette thèse, cette représentation a été adaptée aux metaheuristiques. L'encodage des permutations au moyen de nombres naturels faisant référence a l'ordre d'énumération lexicographique des permutations dans l'arbre du B&B, est proposé comme une nouvelle manière de représenter l'espace de recherche des problèmes 'a permutations dans les metaheuristiques. Cette méthode de codage est basée sur les propriétés mathématiques des permutations, 'a savoir les codes de Lehmer et les tables d'inversions ainsi que les système d'énumération factoriels. Des fonctions de transformation permettant le passage entre les deux représentations (permutations et nombres) ainsi que des opérateurs de recherche adaptes au codage, sont définis pour les problèmes 'a permutations généralisés. Cette représentation, désormais commune aux metaheuristiques et aux algorithmes de B&B, nous a permis de concevoir des stratégies d'hybridation et de collaboration efficaces entre les AGs et le B&B. En effet, deux approches d'hybridation entre les AGs et les algorithmes de B&B (HGABB et COBBIGA) bas'es sur cette représentation commune ont été proposées dans cette thèse. Pour validation, une implémentation a été réalisée pour le problème d'affectation quadratique 'a trois dimension (Q3AP). Afin de résoudre de larges instances de ce problème, nous avons aussi propose une parallélisation pour les deux algorithme hybrides, basée sur des techniques de décomposition d'espace (décomposition par intervalle) utilisées auparavant pour la parallélisation des algorithmes de B&B. Du point de vue implémentation, afin de faciliter de futurs conceptions et implémentations de méthodes hybrides combinant metaheuristiques et méthodes exacte arborescentes, nous avons développe une plateforme d'hybridation intégrée au logiciel pour metaheuristiques, ParadisEO. La nouvelle plateforme a été utilisée pour réaliser des expérimentations intensives sur la grille de calcul Grid'5000.

APA, Harvard, Vancouver, ISO, and other styles

31

Andersen, Johannes Harder. "Linear programming methods for fine grain parallel computers." Thesis, Brunel University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241255.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

朱展強 and Chin-keung Chu. "Parallel computation for time domain boundary element method." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1999. http://hub.hku.hk/bib/B31220678.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Azizian, Kaveh. "Optimum-synthesis methods for cable-driven parallel mechanisms." Thesis, Université Laval, 2012. http://www.theses.ulaval.ca/2012/29255/29255.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Takeda, Kenji. "Parallel discrete vortex methods for viscous flow simulation." Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287340.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Duller, A. W. G. "Parallel computation applied to the finite element method." Thesis, University of Bristol, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376605.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Archibald, Thomas Welsh. "Parallel iterative solution methods for Markov decision processes." Thesis, University of Edinburgh, 1992. http://hdl.handle.net/1842/14792.

Full text

Abstract:

Markov decision processes form an important class of dynamic programming problems because they are widely applicable. However solving real applications of Markov decision processes on serial computers is often impractical due to constraints on memory and processing time. Parallel processing has long been considered a potential solution to the computational intractability of these problems on serial machines, but prior to this work no detailed theoretical or practical studies in this area had been carried out. This thesis examines several successful serial iterative solution methods for infinite horizon, time invariant, discounted Markov decision processes and develops efficient analogous parallel algorithms. Particular consideration is given to the two classes of iterative solution methods known as value iteration methods and reward revision, but the techniques developed and the conclusions drawn are applicable to other iterative methods for Markov decision processes (for example policy iteration methods) and also to iterative methods in general. Iterative methods are applied to many other problem areas including dynamic programming and the solution of linear and differential equations. The main thrust of this thesis is concerned with the optimisation of the performance of the parallel algorithms developed. A detailed analysis of the implementation of several parallel iterative solution methods on a distributed memory, multiple instruction, multiple data, parallel processor reveals the key issues involved in optimising performance. Timing models are developed for processor communication time, processor calculation time and overall run time. These models guide the choice of the connection topology, the communication protocols and the degree of overlapping of communication and calculation. This leads to the development of a phased pipeline algorithm which yields 60 fold speed-ups when a ring of 121 transputers is used to solve problems with 60,000 states and sparse transition structures.

APA, Harvard, Vancouver, ISO, and other styles

37

Navarro, Guerrero Cristóbal Alejandro. "Parallel methods for classical and disordered Spin models." Tesis, Universidad de Chile, 2015. http://repositorio.uchile.cl/handle/2250/136491.

Full text

Abstract:

Doctor en Ciencias, Mención Computación
En las últimas décadas han crecido la cantidad de trabajos que buscan encontrar metodos eficientes que describan el comportamiento macroscópico de los sistemas de spin, a partir de una definición microscópica. Los resultados que se obtienen de estos sistemas no solo sirven a la comunidad fı́sica, sino también a otras áreas como dinámica molecular, redes sociales o problemas de optimización, entre otros. El hecho de que los sistemas de spin puedan explicar fenómenos de otras áreas ha generado un interés global en el tema. El problema es, sin embargo, que el costo computacional de los métodos involucrados llega a ser muy alto para fines prácticos. Por esto, es de gran interés estudiar como la computación paralela, combinada con nuevas estrategias algorı́tmicas, puede generar una mejora en velocidad y eficiencia sobre los metodos actuales. En esta tesis se presentan dos contribuciones; (1) un algoritmo exacto multi-core distribuido de tipo transfer matrix y (2) un método Monte Carlo multi-GPU para la sim- ulación del modelo 3D Random Field Ising Model (RFIM). La primera contribución toma ventaja de las relaciones jerárquicas encontradas en el espacio de configuraciones del problema para agruparlas en árboles de familias que se solucionan en paralelo. La segunda contribución extiende el método Exchange Monte Carlo como un algoritmo paralelo multi-GPU que in- cluye una fase de adaptación de temperaturas para mejorar la calidad de la simulación en las zonas de temperatura mas complejas de manera dinámica. Los resultados muestran que el nuevo algoritmo de transfer matrix reduce el espacio de configuraciones desde O(4^m ) a O(3^m ) y logra un fixed-size speedup casi lineal con aproxi- madamente 90% de eficiencia al solucionar los problemas de mayor tamaño. Para el método multi-GPU Monte Carlo, se proponen dos niveles de paralelismo; local, que escala con GPUs mas rápidas y global, que escala con múltiples GPUs. El método logra una aceleración de entre uno y dos ordenes de magnitud respecto a una implementación de referencia en CPU, y su paralelismo escala con aproximadamente 99% de eficiencia. La estrategia adaptativa de distribución de temperaturas incrementa la taza de intercambio en las zonas que estaban mas comprometidas sin aumentar la taza en el resto de las zonas, generando una simulación mas rápida aun y de mejor calidad a que si se usara una distribución uniforme de temperaturas. Las contribuciones logradas han permitido obtener nuevos resultados para el área de la fı́sica, como el calculo de la matriz transferencia para el kagome lattice en m = 9 y la simulación del modelo 3D Random Field Ising Model en L = {32, 64}.

APA, Harvard, Vancouver, ISO, and other styles

38

CULLEY, ROBERT J. "FDTD METHODS USING PARALLEL COMPUTATIONS AND HARDWARE OPTIMIZATION." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1182524209.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Watkins, Rees Collyer. "Algorithmic skeletons as a method of parallel programming." Thesis, Rhodes University, 1993. http://hdl.handle.net/10962/d1004889.

Full text

Abstract:

A new style of abstraction for program development, based on the concept of algorithmic skeletons, has been proposed in the literature. The programmer is offered a variety of independent algorithmic skeletons each of which describe the structure of a particular style of algorithm. The appropriate skeleton is used by the system to mould the solution. Parallel programs are particularly appropriate for this technique because of their complexity. This thesis investigates algorithmic skeletons as a method of hiding the complexities of parallel programming from the user, and for guiding them towards efficient solutions. To explore this approach, this thesis describes the implementation and benchmarking of the divide and conquer and task queue paradigms as skeletons. All but one category of problem, as implemented in this thesis, scale well over eight processors. The rate of speed up tails off when there are significant communication requirements. The results show that, with some user knowledge, efficient parallel programs can be developed using this method. The evaluation explores methods for fine tuning some skeleton programs to achieve increased efficiency.

APA, Harvard, Vancouver, ISO, and other styles

40

McElfish, Erin Marie. "Methods for parallel amplification of single DNA molecules." Diss., [La Jolla] : University of California, San Diego, 2009. http://wwwlib.umi.com/cr/ucsd/fullcit?p1467961.

Full text

Abstract:

Thesis (M.S.)--University of California, San Diego, 2009.
Title from first page of PDF file (viewed September 17, 2009). Available via ProQuest Digital Dissertations. Includes bibliographical references (p.76-77).

APA, Harvard, Vancouver, ISO, and other styles

41

Chu, Chin-keung. "Parallel computation for time domain boundary element method /." Hong Kong : University of Hong Kong, 1999. http://sunzi.lib.hku.hk/hkuto/record.jsp?B20565574.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Li, Jueyou. "Distributed and parallel methods for structural convex optimization." Thesis, Federation University Australia, 2014. http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/81614.

Full text

Abstract:

There has been considerable recent interest in optimization methods associated with a multi-agent network. The goal is to optimize a global objective function which is a sum of local objective functions only known by the agents through the network. The focus of this dissertation is the development of optimization algorithms for the special class when the optimization problem of interest has an additive or separable structure. Specifically, we are concerned with two classes of convex optimization problems. The first one is called as multi-agent convex problems and they arise in many network applications, including in-network estimation, machine learning and signal processing. The second one is termed as separable convex problems and they arise in diverse applications, including network resource allocation, and distributed model prediction and control. Due to the structure of problems and privacy of local objective functions, special optimization methods are always desirable, especially for large-scale structured problems. For the multi-agent convex problems with simple constraints, we develop gradient-free distributed methods based on the incremental and consensus strategies. The convergence analysis and convergence rates of proposed methods are provided. By comparison, existing distributed algorithms require first-order information of objective functions, but our methods only involve the estimates of objective function value. Therefore, the proposed methods are suitable to solve more general problems even when the first-order information of problems is unavailable or costly to compute. In practical applications a wide variety of problems are formulated as multi-agent optimization problems subject to equality and (or) inequality constraints. Methods available for solving this type of problems are still limited in the literature. Most of them are based on the Lagrangian duality, and there is no estimates on the convergence rate. In the thesis, we develop a distributed proximal-gradient method to solve multi-agent convex problems under global inequality constraints. Moreover, we provide the convergence analysis of the proposed method and obtain the explicit estimates of convergence rate. Our method relies on the exact penalty function method and multi-consensus averaging, not involving the Lagrangian multipliers. For the separable convex problems with linear constraints, on the framework of Lagrangian dual decomposition, we develop fast gradient-based optimization methods, including a fast dual gradient-projection method and a fast dual gradient method. In addition to parallel implementation of the algorithm, our focus is that the algorithm has faster convergence rate, since existing dual subgradient-based algorithms suffer from a slow convergence rate. Our proposed algorithms are based Nesterov’s smoothing technique and several fast gradient schemes. The explicit convergence rates of the proposed algorithms are obtained, which are superior to those obtained by subgradient-based algorithms. The proposed algorithms are applied to a real-pricing problem in smart grid and a network utility maximum problem. Dual decomposition methods often involve in finding the exact solution of an inner subproblem at each iteration. However, from a practical point of view, the subproblem is never solved exactly. Hence, we extend the proposed fast dual gradient-projection method to the inexact setting. Although the inner subproblem is solved only up to certain precision, we provide a complete analysis of computational complexity on the generated approximate solutions. Thus, our inexact version has the attractive computational advantage that the subproblem only needs to be solved with certain accuracy while still maintaining the same iteration complexity as the exact counterpart.
Doctor of Philosophy

APA, Harvard, Vancouver, ISO, and other styles

43

Mahawar, Hemant. "Parallel algorithms for inductance extraction." Texas A&M University, 2003. http://hdl.handle.net/1969.1/5930.

Full text

Abstract:

In VLSI circuits, signal delays play an important role in design, timing verification and signal integrity checks. These delays are attributed to the presence of parasitic resistance, capacitance and inductance. With increasing clock speed and reducing feature sizes, these delays will be dominated by parasitic inductance. In the next generation VLSI circuits, with more than millions of components and interconnect segments, fast and accurate inductance estimation becomes a crucial step. A generalized approach for inductance extraction requires the solution of a large, dense, complex linear system that models mutual inductive effects among circuit elements. Iterative methods are used to solve the system without explicit computation of the system matrix itself. Fast hierarchical techniques are used to compute approximate matrix-vector products with the dense system matrix in a matrix-free way. Due to unavailability of system matrix, constructing a preconditioner to accelerate the convergence of the iterative method becomes a challenging task. This work presents a class of parallel algorithms for fast and accurate inductance extraction of VLSI circuits. We use the solenoidal basis approach that converts the linear system into a reduced system. The reduced system of equations is solved by a preconditioned iterative solver that uses fast hierarchical methods to compute products with the dense coefficient matrix. A GreenÃÂ¢ÃÂÃÂs function based preconditioner is proposed that achieves near-optimal convergence rates in several cases. By formulating the preconditioner as a dense matrix similar to the coefficient matrix, we are able to use fast hierarchical methods for the preconditioning step as well. Experiments on a number of benchmark problems highlight the efficient preconditioning scheme and its advantages over FastHenry. To further reduce the solution time of the software, we have developed a parallel implementation. The parallel software package is capable of analyzing interconnects con- figurations involving several conductors within reasonable time. A two-tier parallelization scheme enables mixed mode parallelization, which uses both OpenMP and MPI directives. The parallel performance of the software is demonstrated through experiments on the IBM p690 and AMD Linux clusters. These experiments highlight the portability and efficiency of the software on multiprocessors with shared, distributed, and distributed-shared memory architectures.

APA, Harvard, Vancouver, ISO, and other styles

44

Ellingworth, H. R. P. "Parallel algorithms for the force-field method in molecular modelling." Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.236102.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Goehlich, Ralph Dietmar. "Design of finite element systems for parallel computers." Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/16817.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Gecgel, Murat. "Parallel, Navier." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/12604807/index.pdf.

Full text

Abstract:

The aim of this study is to extend a parallel Fortran90 code to compute three&ndash
dimensional laminar and turbulent flowfields over rotary wing configurations. The code employs finite volume discretization and the compact, four step Runge-Kutta type time integration technique to solve unsteady, thin&ndash
layer Navier&ndash
Stokes equations. Zero&ndash
order Baldwin&ndash
Lomax turbulence model is utilized to model the turbulence for the computation of turbulent flowfields. A fine, viscous, H type structured grid is employed in the computations. To reduce the computational time and memory requirements parallel processing with distributed memory is used. The data communication among the processors is executed by using the MPI ( Message Passing Interface ) communication libraries. Laminar and turbulent solutions around a two bladed UH &ndash
1 helicopter rotor and turbulent solution around a flat plate is obtained. For the rotary wing configurations, nonlifting and lifting rotor cases are handled seperately for subsonic and transonic blade tip speeds. The results are, generally, in good agreement with the experimental data.

APA, Harvard, Vancouver, ISO, and other styles

47

Thompson, R. T. "Fast sequential and parallel methods for solving multistage stochastic linear programmes." Thesis, University of Essex, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387829.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Chiang, K. (Kuoning). "Parallel processing approach for crash dynamic analysis." Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/17917.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Scheiderer, Stephan. "Effiziente parallele Lattice-Boltzmann-Simulation für turbulente Strömungen." [S.l. : s.n.], 2006. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-28269.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Haider, Shahid Abbas. "Systolic arrays for the matrix iterative methods." Thesis, Loughborough University, 1993. https://dspace.lboro.ac.uk/2134/28173.

Full text

Abstract:

The systolic array research was pioneered by H. T. Kung and C. E. Leiserson. Systolic arrays are special purpose synchronous architectures consisting of simple, regular and modular processors which are regularly interconnected to form an array. Systolic arrays are well suited for computational bound problems in Linear Algebra. In this thesis, the numerical problems, especially iterative algorithms are chosen and implemented on the linear systolic array. same.

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Metodo parallelo'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles