NHSE Software Catalog

Global Arrays

description

http://www.emsl.pnl.gov:2080/docs/global/ga.html
The Global Array (GA) toolkit provides an efficient and portable
"shared-memory" programming interface for distributed-memory computers.
Each process in a MIMD parallel program can asynchronously access logical
blocks of physically distributed matrices, without need for explicit cooperation
by other processes. Unlike other shared-memory environments, the GA model
exposes to the programmer the Non-Uniform Memory Access (NUMA)
characteristics of the High Performance Computers and acknowledges that
access to remote data is slower than to local data. Very efficient access to the
local data is supported.

The package is targeted to a class of
applications in computational chemistry (specifically, computation of the
electronic structure crystalline chemical systems). GA applications may be
written in C or Fortran 77.

The package includes a tool for trace-based animation and visualization
of accesses to distributed arrays.

keywords

virtual shared memory; MIMD machine; nonuniform memory access;
distributed array; execution trace visualization; parallel programming library

environment

PROGRAMMING INTERFACE:

Fortran 77, C; only Fortran (1-based) array indexing is supported

COMMUNICATION HARNESS:

Interrupt-driven communication system on distributed memory
message-passing machines
TCGMSG (using a data-sever model) on networked workstations

PLATFORMS SUPPORTED:

Intel Gamma, Delta, Paragon; SP-1; KSR-1; SGI, SUN Workstation clusters

application

Computational chemistry - electronic structure computation of small or
crystalline structures