Tags: NanoBio Node

Resources (61-80 of 717)

  1. A Multigrid Method for the Self-Adjoint Angular Flux Form of the Radiation-Transport Equation Based on Cellwise Block Jacobi Iteration

    04 Feb 2016 | Online Presentations | Contributor(s): Jeffrey Densmore

    Cellwise block Jacobi iteration is a technique for radiation-transport calculations in which the angular flux for all directions is solved for simultaneously within a spatial cell with the angular...

    http://nanohub.org/resources/23481

  2. Understanding the Propagation of Silent Data Corruption in Algebraic Multigrid

    04 Feb 2016 | Online Presentations | Contributor(s): Jon Calhoun

    Sparse linear solvers from a fundamental kernel in high performance computing (HPC). Exascale systems are expected to be more complex than systems of today being composed of thousands of...

    http://nanohub.org/resources/23483

  3. A Performance Comparison of Algebraic Multigrid Preconditioners on GPUs and MIC

    04 Feb 2016 | Online Presentations | Contributor(s): Karl Rupp

    Algebraic multigrid (AMG) preconditioners for accelerators such as graphics processing units (GPUs) and Intel's many-integrated core (MIC) architecture typically require a careful,...

    http://nanohub.org/resources/23485

  4. Monolithic Multigrid Methods for Coupled Multi-Physics Problems

    04 Feb 2016 | Online Presentations | Contributor(s): Scott Maclachlan

    While block-diagonal and approximate block-factorization preconditioners are often considered for coupled problems, monolithic approaches can offer improved performance, particularly when the...

    http://nanohub.org/resources/23487

  5. Application of Multigrid Techniques to Magnetic and Electromagnetic Systems

    04 Feb 2016 | Online Presentations | Contributor(s): Benjamin Cowan

    We discuss the use of multigrid techniques for several novel systems related to electromagnetics. One of these is the magnetostatic problem, in which systems can involve highly anisotropic and...

    http://nanohub.org/resources/23489

  6. Geometric Multigrid for MHD Simulations with Nedelec Finite Elements on Tetrahedral Grids

    04 Feb 2016 | Online Presentations | Contributor(s): Chris Hansen

    The Magneto-HydroDynamic (MHD) model is used extensively to simulate macroscopic plasma dynamics in Magnetic Confinement Fusion (MCF) devices. In these simulations, the span of time scales from...

    http://nanohub.org/resources/23491

  7. Parallel Multigrid Preconditioner Based on Automatic 3D Tetradedric Meshes

    04 Feb 2016 | Online Presentations | Contributor(s): Frederic Vi

    Multigrid methods are efficient for solving large sparse linear systems. Geometric (GMG) and Algebraic Multigrid (AMG) have both their own benefits and limitations. Combining the simplicity of AMG...

    http://nanohub.org/resources/23493

  8. HPGMG: Benchmarking Computers Using Multigrid

    04 Feb 2016 | Online Presentations | Contributor(s): Jed Brown

    HPGMG (https://hpgmg.org) is a geometric multigrid benchmark designed to measure the performance and versatility of computers. For a benchmark to be representative of applications, good...

    http://nanohub.org/resources/23495

  9. A Scalable Algorithm for Inverse Medium Problems with Multiple Sources

    04 Feb 2016 | Online Presentations | Contributor(s): Keith Kelly

    We consider the problem of acoustic scattering as described by the free-space, time-harmonic scalar wave equation given...

    http://nanohub.org/resources/23498

  10. Support Graph Smoothing Techniques

    04 Feb 2016 | Online Presentations | Contributor(s): Alyson Fox

    Many tasks in large-scale network analysis and simulation require efficient approximation of the solution to the linear system $ Lx=b$, where $ L$ is a graph Laplacian. However, due to the large...

    http://nanohub.org/resources/23500

  11. Task-Graph and Functional Programming Models: The New Paradigm

    04 Feb 2016 | Online Presentations | Contributor(s): Ben Bergen

    The Message Passing Interface (MPI) is an example of a distributed-memory communication model that has served us well through the CISC processor era. However, because of MPI's low-level...

    http://nanohub.org/resources/23502

  12. A Fast Multigrid Approach for Solving the Helmholtz Equation with a Point Source

    04 Feb 2016 | Online Presentations | Contributor(s): Eran Treister

    Solving the discretized Helmholtz equations with high wave numbers in large dimensions is a challenging task. However, in many scenarios, the solution of these equations is required for a point...

    http://nanohub.org/resources/23504

  13. Compatible Relaxation Based Geometric-Algebraic Multigrid

    04 Feb 2016 | Online Presentations | Contributor(s): Fei Cao

    We develop compatible relaxation algorithms for smoothed aggregation-based multigrid coarsening. In the proposed method, we use the geometry of the given discrete problem on the finest level to...

    http://nanohub.org/resources/23506

  14. Hub Snub: Removing Vertices with High Degree from Coarse-grid Correction

    04 Feb 2016 | Online Presentations | Contributor(s): Geoffry Sanders

    Network scientists often employ numerical solutions to linear systems as subroutines of data mining algorithms. Due to the ill-conditioned nature of the systems, obtaining solutions with standard...

    http://nanohub.org/resources/23508

  15. On the Preconditioning of a High-Order RDG-based All-Speed Navier-Stokes Solver

    04 Feb 2016 | Online Presentations | Contributor(s): Brian Weston

    We investigate the preconditioning of an all-speed Navier-Stokes solver, based on the orthogonal-basis Reconstructed Discontinuous Galerkin (RDG) space discretization, and integrated using a...

    http://nanohub.org/resources/23510

  16. Is the Ideal Approximation Operator Always "Ideal" for a Particular C/F Splitting?

    04 Feb 2016 | Online Presentations | Contributor(s): Erin Molloy

    Given a coarse grid, the ideal prolongation operator is defined by , where the weight matrix,  , interpolates a set of fine grid variable (-points) from a set of coarse grid...

    http://nanohub.org/resources/23512

  17. Reducing Communication Costs for Sparse Matrix Multiplication within Algebraic Multigrid

    04 Feb 2016 | Online Presentations | Contributor(s): Grey Ballard

    We consider the sequence of sparse matrix-matrix multiplications performed during the setup phase of algebraic multigrid. In particular, we show that the most commonly used parallel algorithm is...

    http://nanohub.org/resources/23514

  18. Space-time constrained FOSLS with AMGe upscaling

    04 Feb 2016 | Online Presentations | Contributor(s): Panayot Vassilevski

    We consider time-dependent PDEs discretized in combined space-time domains. We first reduce the PDE to a first order system. Very often in practice, one of the equations of the reduced system...

    http://nanohub.org/resources/23516

  19. Multilevel Markov Chain Monte Carlo for Uncertainty Quantification in Subsurface Flow

    04 Feb 2016 | Online Presentations | Contributor(s): Christian Ketelsen

    The multilevel Monte Carlo method has been shown to be an effective variance reduction technique for quantifying uncertainty in subsurface flow simulations when the random conductivity field can...

    http://nanohub.org/resources/23518

  20. Discretization of Elliptic Differential Equations Using Sparse Grids and Prewavelets

    04 Feb 2016 | Online Presentations | Contributor(s): Christoph Pflaum

    Sparse grids can be used to discretize second order elliptic differential equations on a d-dimensional cube. Using Galerkin discretization, we obtain a linear equation system...

    http://nanohub.org/resources/23520