Scotch Brand 5.1.10 - Manual (Page 32)

6.3.3 amk grf
Synopsis
amk grf [input graph file [output target file]] options
Description
The program amk grf turns a source graph file into a decomposition-defined
target file. It computes a recursive bipartitioning of the source graph, as well
as the array of distances between all pairs of its vertices, both of which are
combined to give a decomposition-defined target architecture of same topology
as the input source graph.
The -l option restricts the target architecture to the vertices indicated in the
given vertex list file. It is therefore possible to build a target architecture
made of several disconnected parts of a bigger architecture. Note that this is
not equivalent to turning a disconnected source graph into a target architec-
ture, since doing so would lead to an architecture made of several independent
pieces at infinite distance one from another. Considering the selected vertices
within their original architecture makes it possible to compute the distance
between vertices belonging to distinct connected components, and therefore
to evaluate the cost of the mapping of two neighbor processes onto disjoint
areas of the architecture.
The restriction feature is very useful in the context of multi-user parallel ma-
chines. On these machines, when users request processors in order to run their
jobs, the partitions allocated by the operating system may not be regular nor
connected, because of existing partitions already attributed to other people.
By feeding amk grf with the source graph representing the whole parallel ma-
chine, and the vertex list containing the labels of the processors allocated by
the operating system, it is possible to build a target architecture correspond-
ing to this partition, and therefore to map processes on it, automatically,
regardless of the partition shape.
The -b option selects the recursive bipartitioning strategy used to build the
decomposition of the source graph. For regular, unweighted, topologies, the
’-b(g|h)fx’
recursive bipartitioning strategy should work best. For irregular
or weighted graphs, use the default strategy, which is more flexible. See
also the manual page of function SCOTCH archBuild, page 72, for further
information.
Options
-bstrategy
Use recursive bipartitioning strategy strategy to build the decomposi-
tion of the architecture graph. The format of bipartitioning strategies is
defined within section 7.3.2, at page 59.
-h Display the program synopsis.
-linput vertex file
Load vertex list from input vertex file. As for all other file names, “-”
may be used to indicate standard input.
-V Print the program version and copyright.
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