Tags: UIUC

Online Presentations (41-60 of 459)

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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

  16. High Dimensional Uncertainty Quantification via Multilevel Monte Carlo

    04 Feb 2016 | Online Presentations | Contributor(s): Hillary Fairbanks

    Multilevel Monte Carlo (MLMC) has been shown to be a cost effective way to compute moments of desired quantities of interest in stochastic partial differential equations when the uncertainty in...

    http://nanohub.org/resources/23522

  17. Stable Discretizations and Robust Block Preconditioners for Fluid-Structure Interaction Systems

    04 Feb 2016 | Online Presentations | Contributor(s): Kai Yang

    In our work we develop a family of preconditioners for the linear algebraic systems arising from the arbitrary Lagrangian-Eulerian discretization of some fluid-structure interaction models. After...

    http://nanohub.org/resources/23524

  18. [Illinois] Nanotechnology meets Biology in the Cancer Cell: Applications in Medicine, Drug Delivery, and Determining Drug Efficacy

    04 Feb 2016 | Online Presentations | Contributor(s): Mostafa El-Sayed

    Dr. Mostafa El-Sayed received his B.Sc. from Ain Shams University in Cairo; and Ph.D. from Florida State University. He was Postdoctoral Fellow at Yale University, Harvard University and the...

    http://nanohub.org/resources/23526

  19. [Illinois] Rare Events with Large-Impact: Bioengineering & Clinical Applications of Circulating Tumor Cells

    04 Feb 2016 | Online Presentations | Contributor(s): Mehmet Toner

    Dr. Mehmet Toner is the Helen Andrus Benedict Professor of Biomedical Engineering at the Massachusetts General Hospital (MGH), Harvard Medical School (HMS), and is the co-founding director of the...

    http://nanohub.org/resources/23528

  20. [Illinois] Signal Processing at Light Speed: Ultrashort Optical Pulse Generation with Arbitrary Waveforms

    29 Jan 2016 | Online Presentations | Contributor(s): Claire Mcghee

    We aim to further improve early detection of cancer biomarkers, including metal ion and small molecules, using functional DNA as the selective component for photonic crystal surface enhanced Raman...

    http://nanohub.org/resources/23462