CCC-0760 PARTISN 5.97.

1. NAME OR DESIGNATION OF PROGRAM:  PARTISN 5.97

3. DESCRIPTION OF PROGRAM OR FUNCTION

PARTISN (PARallel, TIme-Dependent SN) is the evolutionary successor to CCC-547/DANTSYS. The PARTISN code package is a modular computer program package designed to solve the time-independent or dependent multigroup discrete ordinates form of the Boltzmann transport equation in several different geometries. The modular construction of the package separates the input processing, the transport equation solving, and the post processing (or edit) functions into distinct code modules: the Input Module, the Solver Module, and the Edit Module, respectively. PARTISN is the evolutionary successor to the DANTSYSTM code system package. The Input and Edit Modules in PARTISN are very similar to those in DANTSYS. However, unlike DANTSYS, the Solver Module in PARTISN contains one, two, and three-dimensional solvers in a single module. In addition to the diamond-differencing method, the Solver Module also has Adaptive Weighted Diamond-Differencing (AWDD), Linear Discontinuous (LD), and Exponential Discontinuous (ED) spatial differencing methods. The spatial mesh may consist of either a standard orthogonal mesh or a block adaptive orthogonal mesh. The Solver Module may be run in parallel for two and three dimensional problems. One can now run 1-D problems in parallel using Energy Domain Decomposition (triggered by Block 5 input keyword npeg>0).  EDD can also be used in 2-D/3-D with or without our standard Spatial Domain Decomposition.
  
Both the static (fixed source or eigenvalue) and time-dependent forms of the transport equation are solved in forward or adjoint mode. In addition, PARTISN now has a probabilistic mode for Probability of Initiation (static) and Probability of Survival (dynamic) calculations. 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.

4. METHODS

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. 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.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

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.

6. 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.

10. REFERENCES

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

- R. E. Alcouffe, R. S. Baker, J. A. Dahl, S.A. Turner, and Robert Ward:
PARTISN: A Time-Dependent, Parallel Neutral Particle Transport Code System,
LA-UR-08-07258 (Revised Nov. 2008)

11. 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, Compaq Alpha and Macintosh 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.

13. SOFTWARE REQUIREMENTS

The program is written in ANSI standard F95 with a few C language routines used to interface to the operating system. A serial mode Windows executable is included in the package; compilers are required on all other systems. PARTISN stresses most f95 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
PGI Fortran compiler version 7.2-5 on X86_64-linux
Intel Fortran Compiler Version 10.0.023 under Linux
Absoft 8.2 on Redhat Enterprise WS 3.0
Macintosh with Absoft
IBM XLF Fortran Compiler on IBM RS/6000
MIPSpro Fortran Compiler Version 7.3.1.3m on SGI
Compaq Fortran Compiler V5.5A.7 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 under RHEL 4 Linux with Intel 10.1.015 and Portland Group Inc, 7.2-2. RSICC also built PARTISN on an Intel Core2 6600 in a Cygwin terminal under Windows Vista SP2 with the Lahey/Fujitsu Fortran 95 compiler Release 7.10.02. This 32-bit serial-mode Windows executable is included in the distribution
  
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.

15. NAME AND ESTABLISHMENT OF AUTHORS

Contributed by:
                Radiation Safety Information Computational Center
                Oak Ridge National Laboratory
                Oak Ridge, Tennessee, U. S. A.
Developed by:   Los Alamos National Laboratory,
                Los Alamos, New Mexico, U.S.A.

fbrs_3d.inp - test case input
fbrs_3d.out - test case ouput
fbrs_3d_VistaRSICC.out
manual.pdf - LANL report
partisn.tar - partisn distribution
partisn_win.exe - Windows exe
Readme_exe.txt - Info file