| Paper |
Title |
Other Keywords |
Page |
| MOM1MP01 |
Massive Tracking on Heterogeneous Platforms
|
simulation, controls, collider, hadron |
13 |
| |
- E. McIntosh, F. Schmidt
CERN, Geneva
- F. de Dinechin
ENS LYON, Lyon
| |
The LHC@home project uses public resource computing to simulate circulating protons in the future Large Hadron Collider (LHC). As the physics simulated may become chaotic, checking the integrity of the computation distributed over a heterogeneous network requires perfectly identical (or homogeneous) floating-point behaviour, regardless of the model of computer used. This article defines an acceptable homogeneous behaviour based on existing standards, and explains how to obtain it. This involves processor, operating system, programming language and compiler issues. In the LHC@home project, imposing this homogeneous behaviour entailed less than 10% performance degradation per processor, and almost doubled the number of processors which could be usefully exploited.
|
|
|
Slides
|
|
|
|
| WEPPP08 |
Computation of transfer maps from magnetic field data in large aspect-ratio apertures
|
wiggler, damping, emittance, linear-collider |
198 |
| |
- C. E. Mitchell, A. Dragt
University of Maryland, College Park, Maryland
| |
Simulations indicate that the dynamic aperture of the proposed ILC Damping Rings is dictated primarily by the nonlinear properties of their wiggler transfer maps. Wiggler transfer maps in turn depend sensitively on fringe-field and high-multipole effects. Therefore it is important to have a detailed and realistic model of the interior magnetic field, including knowledge of high spatial derivatives. Modeling of these derivatives is made difficult by the presence of numerical noise. We describe how such information can be extracted reliably from 3-dimensional field data on a grid as provided, for example, by various 3-dimensional finite element field codes (OPERA-3d) available from Vector Fields. The key ingredients are the use of surface data and the smoothing property of the inverse Laplacian operator. We describe the advantages of fitting on an elliptic cylindrical surface surrounding the beam, as well as extensions to more general domain geometries useful for magnetic elements with large saggitta.
|
|
|
|