Scientific Computing Seminar

Date:

Friday, March 25, 2005

Time:

1:00pm-2:00pm

Location:

50A-5132

Seminar Speaker:

Damian Rouson
Navy Technology Center for Safety and Survivability
Naval Research Laboratory

Title:

Design Metrics in Quantum Turbulence Simulations: How Physics Influences Software Architecture

Abstract:

The information hiding philosophy of object-oriented programming encourages localizing data structures within objects rather than sharing data globally across different classes of objects. This emphasis on local data leads naturally to fine-grained data abstractions, particularly in scientific simulations involving large collections of small, discrete physical or mathematical objects. This talk will focus on a subset of such simulations where dynamically reconfigurable links bind the objects together. It will be demonstrated that fine-grained data structures reduce the complexity of local operations on the data at the potential expense of increased global operation complexity. Two metrics will be used to describe data structures: granularity is the number of instantiations required to represent the problem state space, whereas extent is the continuously traversable length of the data along a given dimension. These definitions will be applied to two abstractions for simulating the turbulent motion of quantum vortices in superfluid liquid helium. Several local and global operations on a fine-grained linked list will be compared with those on a coarse-grained array. It will be demonstrated that fine-grained data structures recover the simplicity of more coarse-grained structures if maximal extent is maintained as the granularity increases. Associated issues of memory management, efficiency and design robustness will be discussed along with a general strategy for componentization using the Common Component Architecture (CCA).

Sponsor of Seminar:

Tony Drummond

Scientific Computing

Contact Esmond G. Ng EGNg@lbl.gov