Provided by: swap-cwm_1.2.1-7_all 
NAME
cant - CAnonicalize N-Triples
DESCRIPTION
CAnonicalize N-Triples
OPTIONS
--verbose
-v Print what you are doing as you go
--help -h Print this message and exit
--from=uri
-f uri Specify an input file (or web resource)
--diff=uri
-d uri Specify a difference file
Can have any number of --from <file> parameters, in which case files are merged. If none are given,
/dev/stdin is used.
If any diff files are given then the diff files are read merged separately and compared with the input
files. the result is a list of differences instead of the canonicalizd graph. This is NOT a minimal diff.
Exits with nonzero system status if graphs do not match.
This is an independent n-triples cannonicalizer. It uses heuristics, and will not terminate on all
graphs. It is designed for testing: the output and the reference output are both canonicalized and
compared.
It uses the very simple NTriples format. It is designed to be independent of the SWAP code so that it can
be used to test the SWAP code. It doesn't boast any fancy algorithms - just tries to get the job done for
the small files in the test datasets.
The algorithm to generate a "signature" for each bnode. This is just found by looking in its immediate
viscinity, treating any local bnode as a blank. Bnodes which have signatures unique within the graph can
be allocated cannonical identifiers as a function of the ordering of the signatures. These are then
treated as fixed nodes. If another pass is done of the new graph, the signatures are more distinct.
This works for well-labelled graphs, and graphs which don't have large areas of interconnected bnodes or
large duplicate areas. A particular failing is complete lack of treatment of symmetry between bnodes.
References:
.google graph isomorphism See also eg
http://www.w3.org/2000/10/rdf-tests/rdfcore/utils/ntc/compare.cc NTriples: see
http://www.w3.org/TR/rdf-testcases/#ntriples
Not to mention,
published this month by coincidence:
Kelly, Brian, [Whitehead Institute]
"Graph cannonicalization", Dr Dobb's Journal, May 2003.
$Id: cant.py,v 1.15 2007/06/26 02:36:15 syosi Exp $
This is or was http://www.w3.org/2000/10/swap/cant.py W3C open source licence
<http://www.w3.org/Consortium/Legal/copyright-software.html>.
2004-02-31 Serious bug fixed. This is a test program, shoul dbe itself tested.
Quis custodiet ipsos custodes?