Sökning: "deflation"

Visar resultat 11 - 15 av 17 avhandlingar innehållade ordet deflation.

  1. 11. Identification and tuning of algorithmic parameters in parallel matrix computations : Hessenberg reduction and tensor storage format conversion

    Författare :Mahmoud Eljammaly; Bo Kågström; Lars Karlsson; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : This thesis considers two problems in numerical linear algebra and high performance computing (HPC): (i) the parallelization of a new blocked Hessenberg reduction algorithm using Parallel Cache Assignment (PCA) and the tunability of its algorithm parameters, and (ii) storing and manipulating dense tensors on shared memory HPC systems.The Hessenberg reduction appears in the Aggressive Early Deflation (AED) process for identifying converged eigenvalues in the distributed multishift QR algorithm (state-of-the-art algorithm for computing all eigenvalues for dense square matrices). LÄS MER

  3. 12. Past environment and sediment dynamics in the Black Sea-Caspian Sea region from Southern Russian loess sequences

    Författare :Chiara Amalia Költringer; Thomas Stevens; Bjarne Almqvist; Ian Snowball; Kathryn Fitzsimmons; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Loess deposits are excellent past climate and environment archives and contain records of aeolian mineral dust accumulation. Loess deposits stretch across Eurasia and sequences along the Lower Volga in the Northern Caspian lowland in the South East European Plain represent a key link between European and Asian loess. LÄS MER

  4. 13. Regional wages and labour market integration in Sweden, 1732-2009

    Författare :Kristoffer Collin; Göteborgs universitet; []
    Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Löner; Arbetsmarknad; Wages; Labor market; Sverige;

    Sammanfattning : This dissertation consists of an introduction, four research papers and two papers that describe the data collected. Three county-specific data sets were constructed: one wage data set for the manufacturing sector, one wage data set for the agricultural sector, and one cost-of-living data set. LÄS MER

  5. 14. Eigenfrequency Analysis FE-Adaptivity and a Nonlinear Eigenproblem Algorithm

    Författare :Patrik Hager; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; nonlinear eigenvalue; finite element; adaptivity; superconvergent patch recovery; rational krylov;

    Sammanfattning : Engineering often pose the problem of computing the frequencies with which a system oscillates and the corresponding displacement patterns the system forms, and in case damping is present then the rates of which the amplitudes of the displacement patterns decay are also required. It is necessary to compute these quantities within a prescribed accuracy and the effort required for the computations should be minimised. LÄS MER

  7. 15. Parallel Algorithms and Library Software for the Generalized Eigenvalue Problem on Distributed Memory Computer Systems

    Författare :Björn Adlerborn; Bo Kågström; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; computer and systems sciences; data- och systemvetenskap;

    Sammanfattning : We present and discuss algorithms and library software for solving the generalized non-symmetric eigenvalue problem (GNEP) on high performance computing (HPC) platforms with distributed memory. Such problems occur frequently in computational science and engineering, and our contributions make it possible to solve GNEPs fast and accurate in parallel using state-of-the-art HPC systems. LÄS MER