Scotch Brand 5.1.10 - Manual (Page 34)

c Chaco v1.0 /MeTiS format.
m The Matrix Market format.
s Scotch source graph format.
-V Print the program version and copyright.
Default option set is “-Ib0 -Os”.
6.3.6 gmap / gpart
Synopsis
gmap [input graph file [input target file [output mapping file [output log file]]]]
options
gpart number of parts [input graph file [output mapping file [output log file]]]
options
Description
The program gmap is the graph mapper. It uses a partitioning strategy to
map a source graph onto a target graph, so that the weight of source graph
vertices allocated to target vertices is balanced, and the communication cost
function f
C
is minimized.
The implemented mapping methods mainly derive from graph theory.
In particular, graph geometry is never used, even if it is available; only
topological properties are taken into account. Mapping methods are used to
define mapping strategies by means of selection, combination, grouping, and
condition operators.
The only mapping method implemented in version 5.1 is the Dual Recursive
Bipartitioning algorithm, which uses graph bipartitioning methods. Avail-
able bipartitioning methods include a multi-level algorithm that uses other
bipartitioning methods to compute the initial and refined bipartitions, an
improved implementation of the Fiduccia–Mattheyses heuristic designed to
handle weighted graphs, a greedy method derived from the Gibbs, Poole, and
Stockmeyer algorithm, the greedy graph growing heuristic, and a greedy “ex-
actifying” refinement algorithm designed to balance vertex loads as much as
possible; random and backtracking methods are also provided.
gpart is a simplified interface to gmap, which performs graph partitioning
instead of static mapping. Consequently, the desired number of parts has to
be provided, in lieu of the target architecture.
The -b and -c options allow the user to set preferences on the behavior of the
mapping strategy which is used by default. The -m option allows the user to
define a custom mapping strategy.
If mapping statistics are wanted rather than the mapping output itself, map-
ping output can be set to /dev/null, with option -vmt to get mapping statis-
tics and timings.
Options
Since the program is devoted to experimental studies, it has many optional
parameters, used to test various execution modes. Values set by default will
give best results in most cases.
34