SCHEDULE: NOV 10-16, 2012
When viewing the Technical Program schedule, on the far righthand side is a column labeled "PLANNER." Use this planner to build your own schedule. Once you select an event and want to add it to your personal schedule, just click on the calendar icon of your choice (outlook calendar, ical calendar or google calendar) and that event will be stored there. As you select events in this manner, you will have your own schedule to guide you through the week.
A Parallel Two-Level Preconditioner for Cosmic Microwave Background Map-Making
SESSION: Numerical Algorithms
EVENT TYPE: Papers
TIME: 1:30PM - 2:00PM
SESSION CHAIR: Costas Bekas
AUTHOR(S):Laura Grigori, Radek Stompor, Mikolaj Szydlarski
In this work we study performance of two-level preconditioners in the context of iterative solvers of the generalized least square systems, where the weights are assumed to be described by a block-diagonal matrix with Toeplitz blocks. Such cases are physically well motivated and arise whenever the instrumental noise displays a piece-wise stationary behavior. Our iterative algorithm is based on a conjugate gradient method with a parallel two-level preconditioner (2lvl-PCG) for which we construct its coarse space from a limited number of sparse vectors estimated solely from coefficients of the initial linear system. Our prototypical application is the map-making problem in the Cosmic Microwave Background observations. We show experimentally that our parallel implementation of 2lvl-PCG outperforms by as much as a factor of 5 the standard one-level PCG in terms of both the convergence rate and the time to solution.
Costas Bekas (Chair) - IBM Research - Zurich
Laura Grigori - INRIA
Radek Stompor - Paris Diderot University
Mikolaj Szydlarski - INRIA