RSICC CODE PACKAGE CCC‑707

 

 

1.   NAME AND TITLE

PARTISN 4.00: Time-Dependent, Parallel Neutral Particle Transport Code System.

 

2.   CONTRIBUTOR

Los Alamos National Laboratory, Los Alamos, New Mexico.

 

3.   CODING LANGUAGE AND COMPUTER

Fortran 90 and C; IBM, SGI, Alpha, Cray and PC - Linux and Windows (C00707MNYCP01).

 

4.   NATURE OF PROBLEM SOLVED

PARTISN (PARallel, TIme-Dependent SN) is the evolutionary successor to CCC-547/DANTSYS. User input and cross section formats are very similar to that of DANTSYS. The linear Boltzmann transport equation is solved for neutral particles using the deterministic (SN) method. Both the static (fixed source or eigenvalue) and time-dependent forms of the transport equation are solved in forward or adjoint mode. Vacuum, reflective, periodic, white, or inhomogeneous boundary conditions are solved. General anisotropic scattering and inhomogeneous sources are permitted. PARTISN solves the transport equation on orthogonal (single level or block-structured AMR) grids in 1-D (slab, two-angle slab, cylindrical, or spherical), 2-D (X-Y, R-Z, or R-T) and 3-D (X-Y-Z or R-Z-T) geometries.

 

5.   MTHOD OF SOLUTION

PARTISN numerically solves the multigroup form of the neutral-particle Boltzmann transport equation. The discrete-ordinates form of approximation is used for treating the angular variation of the particle distribution. For curvilinear geometries, diamond differencing is used for angular discretization. The spatial discretizations may be either low-order (diamond difference or Adaptive Weighted Diamond Difference (AWDD)) or higher-order (linear discontinuous or exponential discontinuous). Negative fluxes are eliminated by a local set-to-zero-and-correct algorithm for the diamond case (DD/STZ). Time differencing is Crank-Nicholson (diamond), also with a set-to-zero fixup scheme. Both inner and outer iterations can be accelerated using the diffusion synthetic acceleration method, or transport synthetic acceleration can be used to accelerate the inner iterations. The diffusion solver uses either the conjugate gradient or multigrid method. Chebyshev acceleration of the fission source is used. The angular source terms may be treated either via standard PN expansions or Galerkin scattering. An option is provided for strictly positive scattering sources. Parallelization is performed via a 2-D spatial decomposition, which retains the ability to invert the source iteration equation in a single sweep. First-collision source treatment options are provided for the elimination of primary ray effects in fixed-source calculations. Automatic mesh coarsening is also provided for efficient solutions.

 

6.       RESTRICTIONS OR LIMITATIONS

The code is thoroughly variably dimensioned, with memory requirements determined from the input parameters. Out-of-core (i.e., disk) storage capability options are provided for the flux moments and time-dependent angular fluxes.

 

 

7.   TYPICAL RUNNING TIME


Running time on a single processor is directly related to problem size and to central processor and data transfer speeds. On a SGI R10000, a four-group eigenvalue calculation of an X-Y-Z model of the Fast Test Reactor (FTR) took 9 seconds. The calculation used transport corrected P0 cross sections, an S8 angular quadrature, DD/STZ spatial differencing, and a 14x14x30 spatial mesh. Running time on parallel platforms is sensitive to the latency and topology of the interconnect, as well as the single processor performance.

 

8.   COMPUTER HARDWARE REQUIREMENTS

The current release is designed for UNIX, Linux or Windows systems. It has been implemented on Linux PC, Windows PC, SGI, IBM RS/6000, and Compaq Alpha workstations. The workstation versions use double precision arithmetic. The program has been run in parallel on clusters of SGI workstations, IBM SP2, Compaq Alphas, and PC Linux. MPI libraries and INCLUDE files are required to build parallel executables. The virtual machine memory must be large enough for the problem being executed. On many architectures, stack size limits must be large enough to allow the placement of temporary arrays on the stack.

 

9.   COMPUTER SOFTWARE REQUIREMENTS

The program is written in ANSI standard F90 with a few C language routines used to interface to the operating system. No executables are included in the package, so compilers are required on all systems. PARTISN stresses most f90 compilers, so please ensure that the compiler version you are using is at least as recent as the one listed below on which the LANL developers ran the code system.

·         Lahey‑Fujitsu LF95 Fortran Compiler Version 6.20 on Intel PC running Linux

·         Absoft 8.2 on Redhat Enterprise WS 3.0

·         IBM XLF Fortran Compiler Version 7.1.0.3 on IBM RS/6000

·         MIPSpro Fortran Compiler Version 7.3.1.3m on SGI

·         Compaq Fortran Compiler V5.5.0‑1 on Compaq Alpha under Digital Unix

·         Cray J90 and T90 with CF90 Version 3.0.2.1

·         Lahey-Fujitsu Fortran Compiler version 7.1 under Windows in a Cygwin environment

RSICC tested this release in serial mode on IBM RS/6000 under AIX 5.1 with XL Fortran 08.01.0000.0003 and on a Pentium IV running WindowsXP SP2 with Lahey/Fujitsu Fortran 95 Compiler Release 7.10.02 and in parallel and serial modes on AMD Athlon with Lahey/Fujitsu Fortran 95 L6.10a under Red Hat Linux 7.3.

Parallelization is performed using MPI. Where available, POSIX routines are used to obtain the machine name, cross section path, and access rights. Otherwise, system-specific routines must be used. In addition to Fortran and C compilers, program building requires GNUmake (Version 3.74 or later), GNU awk (Version 3.0 or later), and cpp. A Readme file in the top program directory contains build instructions.

PARTISN is modularly structured in a form that separates the input and output (edit) functions from the main calculational (solver) section of the code. The code makes use of binary, sequential data files, called interface files, to transfer data between modules. Standard interface files whose specifications have been defined by the Reactor Physics Committee on Computer Code Coordination are accepted, used, and created by the code. A free-field card-image input capability is provided for the user. The code provides the user with considerable flexibility in using both card-image or sequential file input and in controlling the execution of modules.

 

10. REFERENCES


a: included in documentation:

R. E. Alcouffe, R. S. Baker, J. A. Dahl, S.A. Turner, and Robert Ward, gPARTISN: A Time-Dependent, Parallel Neutral Particle Transport Code System,h LA-UR-05-3925 (May 2005).

b: background information:

R. E. Alcouffe, R. S. Baker, F. W. Brinkley, D. R. Marr, R. D. OfDell, and W. F. Walters, gDANTSYS: A Diffusion Accelerated Neutral Particle Code System,h LA-12969-M (1995). 

 

11. CONTENTS OF CODE PACKAGE

Included are the referenced document in 10.a and a tar file which contains PARTISN source files, installation procedures, and a test case.

 

12. DATE OF ABSTRACT

January 2003, revised October 2005.

 

KEYWORDS:   ADJOINT; DISCRETE ORDINATES; GAMMA‑RAY; MULTIGROUP; NEUTRON; SPHERICAL GEOMETRY; SLAB; CYLINDRICAL GEOMETRY; WORKSTATION; COMPLEX GEOMETRY