Elsevier Science Home
Computer Physics Communications Program Library
Full text online from Science Direct
Programs in Physics & Physical Chemistry
CPC Home

[Licence| Download | New Version Template] adaz_v1_1.tar.gz(131 Kbytes)
Manuscript Title: FARM_2DRMP: a version of FARM for use with 2DRMP
Authors: V.M. Burke, C.J. Noble, V. Faro-Maza, A. Maniopoulou, N.S. Scott
Program title: FARM_2DRMP
Catalogue identifier: ADAZ_v1_1
Distribution format: tar.gz
Journal reference: Comput. Phys. Commun. 180(2009)2450
Programming language: Fortran 95 and MPI.
Computer: Tested on CRAY XT4 [1]; IBM eServer 575 [2]; Itanium II cluster [3].
Operating system: Tested on UNICOS/lc [1]; IBM AIX [2]; Red Hat Linux Enterprise AS [3].
Has the code been vectorised or parallelized?: Yes. 16 cores were used for the small test run.
Keywords: atomic collision processes, electron impact excitation, electron impact ionization, intermediate energies, IERM, R-matrix, RMPS, two-dimensional R-matrix propagation.
PACS: 34.80.Dp.
Classification: 2.4.

External routines: BLAS, LAPACK

Does the new version supersede the previous version?: No

Nature of problem:
The program solves the scattering problem in the asymptotic region of R-matrix theory where exchange is negligible.

Solution method:
A radius is determined at which the wave function, calculated as a Gailitis expansion [4] with accelerated summing [5] over terms, converges. The R-matrix is propagated from the boundary of the internal region to this radius and the K-matrix calculated. Collision strengths or cross sections may be calculated.

Reasons for new version:
To complete the 2DRMP package [6] an asymptotic program, such as FARM [7], is needed. The original version of FARM is designed to construct the physical R-matrix, R, from surface amplitudes contained in the H-file. However, in 2DRMP, R, has already been constructed for each scattering energy during propagation and each R is stored in one of the RmatT files described in Fig. 8 of [6]. Therefore, this modified version of FARM, known as as FARM_2DRMP, has been developed solely for use with 2DRMP. Instructions on its use and corresponding test data is provided with 2DRMP [6].

Summary of revisions:
FARM_2DRMP contains two codes, farm.f and farm_par.f90. The former is a serial code while the latter is a parallel F95 code that employs an MPI harness to enable the nenergy energies to be computed simultaneously across ncore cores, with each core processing either ⌊ nenergy / ncore ⌋ or ⌈ nenergy / ncore ⌉ energies. The input files, input.d and H, and the output file farm.out are as described in [7]. Both codes read R directly from RmatT.

FARM_2DRMP is for use solely with 2DRMP and for a specified L,S and ∏ combination. The energy range specified in input.d must match that specified in energies.data.

Running time:
The wall clock running time for the small test run using 16 cores and performed on [3] is 9 secs.

[1] HECToR, CRAY XT4 running UNICOS/lc, http://www.hector.ac.uk/ (visited 22 July, 2009).
[2] HPCx, IBM eServer 575 running IBM AIX , http://www.hpcx.ac.uk/ (visited 22 July, 2009)
[3] HP Cluster,Itanium II cluster running Red Hat Linux Enterprise AS, Queen s University Belfast, http://www.qub.ac.uk/directorates/InformationServices/ Research/HighPerformanceComputing/Services/Hardware/HPResearch/(visited (22 July, 2009).
[4] M. Gailitis, J. Phys. B 9(1976)843.
[5] C.J. Noble and R.K. Nesbet, Comput. Phys. Commun. 33(1984)399.
[6] N.S. Scott, M.P. Scott, P.G. Burke, T. Stitt, V. Faro-Maza, C. Denis and A. Maniopoulou, Comput. Phys. Commun. this issue.
[7] V.M. Burke and C.J. Noble, Comput. Phys. Commun. 85(1995)471.