PROGRAM SUMMARY
Title of program:
FDCD
Catalogue identifier:
ADQJ
Ref. in CPC:
148(2002)242
Distribution format: tar gzip file
Operating system: Windows 2000, FreeBSD
High speed store required:
2MK words
Number of bits in a word:
32
Number of lines in distributed program, including test data, etc:
1299
Keywords:
Conserved density, Finite difference equations, Computer algebra,
REDUCE.
Programming language used: Reduce 3.6, Rlisp
Computer:
PC/AT compatible machine.
Nature of physical problem:
The existence of conserved densities for difference-difference equations
is of interest for their classification and for understanding the
stability of their solutions.
Restrictions:
The program can handle explicit difference-difference equations and
nonlinear difference equations which can be transformed to polynomial
ones.
Typical running time:
It depends on the equation and the rank of the conserved density. It
increases exponentially with the rank of the conserved density. Table 1
shows the running times on the PC Pentium with operating systems Windows
2000 (Pentium III, 600MHz) and FreeBSD (Pentium 4, 2GHz). Timings are
given in milliseconds.
Table 1. Performance on Windows (FreeBSD)
------------------------------------------------------------------------
| rank
example |---------------------------------------------------------------
| 1 | 2 | 3 | 4 | >=5
--------|--------|---------|--------------|-----------------|-----------
1 | 10 (1) | 20 (2) | 80 (27) | 1715655 (**) | ** (**)
| | | | |
2 | 10 (1) | 20 (5) | 2033 (3630) | ** (**) | ** (**)
| | | | |
3 | 10 (1) | 20 (5) | 180 (53) | 33308 (50569) | ** (**)
------------------------------------------------------------------------
the cases ** were rejected by memory error.