CRPC-TR98766						February 1998

Title: PCE-QUAL-ICM: A Parallel Water Quality Model Based on CE-QUAL-ICM

Authors: S. Chippada, C. Dawson, V.J. Parr, M.F. Wheeler, C. Cerco, B. 
Bunch, and M. Noel

Submitted September 1998; Available as CEWES MSRC Technical Report 98-10

Abstract:
CE-QUAL-ICM is a three-dimensional eutrophication model developed at the
U.S. Army Corps of Engineers Waterways Experiment Station (CEWES),
Vicksburg, MS. This water quality model is semi-explicit in time, and is
based on an unstructured cell-centered finite volume numerical method. The
hydrodynamics data such as velocities and turbulent diffusion are read in
externally, and the model computes the advection-diffusion-reaction of a
number of physical and state variables such as temperature, salinity,
sediments, oxygen, algae, etc.  This sequential FORTRAN 77 code was
parallelized using data/domain decomposition strategy and a single
program, multiple data (SPMD) paradigm. WQMPP, a pre/post processor for
the water quality model which splits the global domain into a specified
number of smaller subdomains and sets up the local data files and message
passing tables, has been developed. WQMPP, when run in post-processor mode
also combines the local subdomain output to produce global output in a
format similar to that produced by the original CE-QUAL-ICM code.
PCE-QUAL-ICM, the parallel water quality model enhances CE-QUAL-ICM with
message passing. Inter-processor communication is done using MPI
communication libraries and the parallel code has been ported onto the
CRAY-T3E, IBM-SP2 and SGI O2000. This paper explains the domain
decomposition and parallelization strategy employed in WQMPP and
PCE-QUAL-ICM.

------------------------------------------------------------------------------
S. Chippada			C. Dawson
chippada@ticam.utexas.edu	clint@ticam.utexas.edu
V.J. Parr			M.F. Wheeler
				mfw@ticam.utexas.edu
Texas Institute for Computational and Applied Mathematics
University of Texas at Austin

C. Cerco		B. Bunch		M. Noel
cerco@wes.army.mil	bunchb@wes.army.mil
Waterways Experiment Station
Vicksburg, MS