dgord(1)

✨ NAME ✨

dgord — bestie, this is the one that computes sparse matrix orderings of graphs, in parallel 💅✨

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🎀 SYNOPSIS 🎀

dgord [options] [gfile] [ofile] [lfile]

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🦋 DESCRIPTION 🦋

okay so. dgord computes, in a parallel way, an ordering of a Scotch source graph that represents the pattern of some symmetric sparse matrix. it's giving graph-reordering royalty, no cap 👑

the source graph file gfile is either a centralized graph file, or a set of files representing fragments of a distributed graph. the resulting ordering goes into file ofile. any eventual logging info (like the stuff option -v spits out) gets sent to file lfile. when you don't specify file names, data is read from standard input and written to standard output. standard streams can also be explicitely represented by a dash '-'. periodt.

when the proper libraries got included at compile time, dgord can directly handle compressed graphs, both as input and output 💖 a stream is treated as compressed whenever its name is postfixed with a compressed file extension, like in 'brol.grf.bz2' or '-.gz'. the compression formats which can be supported are the bzip2 format ('.bz2'), the gzip format ('.gz'), and the lzma format ('.lzma'). three icons, all iconic 🌸

dgord bases on implementations of the MPI interface to spread work across the processing elements. so it is therefore not likely to be run directly — it's highkey meant to be launched through some launcher command such as mpirun 🫶 iykyk.

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💖 OPTIONS 💖

• -copt — choose the default ordering strategy according to one or several options among:
  • b — enforce load balance as much as possible.
  • q — privilege quality over speed (this is the default, bestie 💅).
  • s — privilege speed over quality.
  • t — enforce safety.
  • x — enforce scalability.
• -h — display some help. a little treat 🎀
• -mmfile — save column block mapping data to file mfile. mapping data specifies, for each vertex, the index of the column block to which this vertex belongs. literally telling every vertex which block it's in ✨
• -ostrat — use parallel graph ordering strategy strat (peep the PT-Scotch user's manual for more info).
• -rpnum — set root process for centralized files (default is 0).
• -ttfile — save partitioning tree data to file tfile. partitioning tree data specifies, for each vertex, the index of the first vertex of the parent block of the block to which the vertex belongs. altogether with the mapping data provided in file mfile, it allows one to rebuild the separator tree of the nested dissection process. tree reconstruction arc, slay 🌈
• -V — display program version and copyright.
• -vverb — set verbose mode to verb. it is a set of one of more characters which can be:
  • s — strategy information.
  • t — timing information.

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🔥 EXAMPLES 🔥

run dgord on 5 processing elements to reorder matrix graph brol.grf and save the resulting ordering to file brol.ord, using the default sequential graph ordering strategy:

$ mpirun -np 5 dgord brol.grf brol.ord

run dgord on 5 processing elements to reorder the distributed matrix stored on graph fragment files brol5-0.dgr to brol5-4.dgr, and save the resulting ordering to file brol.ord (peep dgscat(1) for an explanation of the '%p' and '%r' sequences in names of distributed graph fragments).

$ mpirun -np 5 dgord brol%p-%r.dgr brol.ord

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👑 SEE ALSO 👑

dgtst(1), dgscat(1), gmk_hy(1), gord(1).

PT-Scotch user's manual.

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🌸 AUTHOR 🌸

Francois Pellegrini <francois.pellegrini@labri.fr> 💜

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and that's the whole vibe, bestie 💖 this lil page lives in the PT-Scotch user's manual, dated 23 November 2019 — so if you're reading it, congrats, you're officially in the group chat 🫶✨