RSL Papers and Software
(see bottom of this page for software download information)

RSL: A Parallel Runtime System Library for Regional Atmospheric Models with Nesting

John Michalakes


RSL is a parallel runtime system library developed at Argonne National Laboratory that is tailored to regular-grid atmospheric models with mesh refinement in the form of two-way interacting nested grids. RSL provides high-level stencil and interdomain communication, irregular domain decomposition, automatic local/global index translation, distributed I/O, and dynamic load balancing. RSL was used with Fortran90 to parallelize a well-known and widely used regional weather model, the Penn State/NCAR Mesoscale Model.

To appear in proceedings of the IMA workshop "Structured Adaptive Mesh Refinement Grid Methods", eds. S. Baden, N. Chrisochoides, D. Gannon, and M. Norman Minneapolis, March 12-13, 1997. Springer-Verlag. Also preprint ANL/MCS-P663-0597.

Download ANL/MCS-P663-0597
(16 pages; 98 KB, Gzipped PostScript)

A Runtime System Library for Parallel Finite Difference Models with Nesting

John Michalakes


RSL is a parallel run-time system library for implementing regular-grid models with nesting on distributed memory parallel computers. RSL provides support for automatically decomposing multiple model domains and for redistributing work between processors at run time for dynamic load balancing. A unique feature of RSL is that processor subdomains need not be rectangular patches; rather, grid points are independently allocated to processors, allowing more precisely balanced allocation of work to processors. Communication mechanisms are tailored to the application: RSL provides an efficient high-level stencil exchange operation for updating subdomain ghost areas and interdomain communication to support two-way interaction between nest levels. RSL also provides run-time support for local iteration over subdomains, global-local index translation, and distributed I/O from ordinary Fortran record-blocked data sets. The interface to RSL supports Fortran77 and Fortran90. RSL has been used to parallelize the NCAR/Penn State Mesoscale Model (MM5).

Download ANL/MCS-TM-197
(39 pages; 103KB, Gzipped PostScript)

Download RSL and on-line example Fortran code from technical memorandum
ANL/MCS-TM-197 here (gzipped tar file; 175KB).

Reference Manual for RSL

John Michalakes

Download Draft ANL/MCS-TM-224
(62 pages; 84KB, Gzipped PostScript)


RSL is copyrighted software (see notice). It is distributed free for public use
as part of the PSU/NCAR Mesoscale Model (MM5) distribution from NCAR.

RSL is also available in stand-alone form here (gzipped tar file; 175KB).
Please see the README file for additional information.

This page last modified Oct. 2, 1998.