What is Sci DAC Scientific Discovery through Advanced

What is Sci. DAC? “Scientific Discovery through Advanced Computing” • New DOE program started in October 2001 • Total budget ~ $70 M/year • Duration ~ 5 years Three types of activities • Science Applications – Global Climate – Accelerator Technology, Fusion, Astrophysics • Integrated Software Infrastructure Centers (ISICs) – Performance, Adaptive grids, … • National Collaboratories and Networking – Earth System Grid, …

Sci. DAC Global Climate Projects

Sci. DAC CCSM Collaborative Development Cooperative initiative on CCSM development • 6 DOE labs (ANL, LBNL, LLNL, ORNL, PNNL), NASA/DAO, and NCAR • DOE PIs: Bob Malone (LANL) and John Drake (ORNL) • Coordinate with SSC, WGs, CCSM team, NASA ESMF Focus is on • Model extensibility, component interchangeability • Portability – Across range of current architectures – Adaptable to foreseeable future directions • Performance • Dynamical cores – Spatial gradients imply interprocessor communications

Examples of Generic Development Activities Software engineering • Requirements and design documents for each component model • Rigorous review of code and proposed changes (CRBs) • Suite of tests to be applied before changes are incorporated • Conform to CCSM software development guidelines Documentation • Keep design document and user documentation up to date Maintain compatibility with • CCSM plans, SSC guidelines, WG objectives • NASA HPCC Earth System Modeling Framework (ESMF) • Common Component Architecture (CCA) Issues • Object-oriented approach? • Can it be done in Fortran 90? • If prefer C++, must solve language interoperability problem

Examples of Model Development Activities Atmospheric model • Continues work of CHAMMPions and ACPI Avant Garde • Improved parallelism, cache utilization, data structures, modularity • Higher resolution (T 85, T 170) • Add atmospheric chemistry, sub-grid precipitation parameterization Coupler • Model Coupling Toolkit (MCT) • Supports both synchronous and asynchronous coupling modes • Designed for compatibility with ESMF and CCA Ocean model • Improved parallelism, cache utilization, data structures, modularity • Hybrid z-isopycnal vertical coordinate with ALE remapping (HYPOP) • Monotone incremental remapping horizontal advection/transport • Add biogeochemistry Sea ice model • Monotone incremental remapping horizontal advection/transport

Mechanisms for Coordinating Activities Weekly teleconference calls (each Monday) • Pick topic(s) in advance • Currently announced only to institutional PIs Monthly Access Grid meetings • Pick topic(s) in advance • Currently announced only to institutional PIs • Can easily enlarge audience Detailed task lists • Who is doing what when? • Currently primarily limited to Sci. DAC activities • Need to integrate Sci. DAC and NCAR activities Active Sci. DAC participation in CCSM Working Groups