PROGRAM SUMMARY
Title of program:
Foam++, version 2.05
Catalogue identifier:
ADRG
Ref. in CPC:
152(2003)55
Distribution format: tar gzip file
Operating system: UNIX (Linux 6.x)
High speed store required:
50MK words
Number of lines in distributed program, including test data, etc:
9435
Keywords:
Monte Carlo (MC) simulation and generation, Particle physics,
Phase space, Computational methods, Utility.
Programming language used: C++
Computer:
PC 550 MHZ Intel chip .
Other versions of this program:
Cat. Id. Title Ref. in CPC ADMC Foam, version 1.01 130(2000)244 ADRL FoamF77, version 2.05 152(2003)55
Nature of physical problem:
Monte Carlo simulation or generation of unweighted (weight equal 1)
events is a standard problem in many areas of research. It is highly
desirable to have in the program library a general-purpose numerical
tool (program) with a MC generation algorithm featuring built-in
capability of adjusting automatically the generation procedure to an
arbitrary pattern of singularities in the probability distribution. Our
primary goal is simulation of the differential distribution in the
multiparticle Lorentz invariant phase space for the purpose of
comparison between Quantum Field Theory prediction and experiments in
the high energy experiments.
Method of solution:
In the algorithm, a grid (foam) of cells is built in the process of the
binary split of the cells. The resulting foam is adapted automatically
to the shape of the integrand in such a way that the resulting ration of
average weight to maximum weight or variance to average weight is
arbitrarily good. The above algorithm, is a substantial improvement on
the previous version in Ref. [1]. The divisionof the cell is improved
and, in addition to cells of a simplical shape of Ref. [1],
hyperrectangular cells are also used.
Restrictions:
The program is memory-hungry and therefore limited, at present, to
relatively small dimensions <= 16. (In Foam 1.x of Ref. [1] the
dimension was limited to n<=6.)
Typical running time:
The CPU time necessary to build up a foam of cells depends strongly on
the number of dimensions and the requested size of the grid. On the PC
with a 550 MHz Intel chip, it takes about 30 seconds to build a
hyperrectangular grid of 10000 cells for a simple 3-dimensional
distribution.
References:
[1] S. Jadach, Comput. Phys. Commun. 130, 244 (2000).