Graph.isIsomorphicWith(Graph g);
Model.isIsomorphicWith(Model m);
On 09/12/17 06:08, Claude Warren wrote:
I am not sure what digest you mean but the fuaeki graphs do have an
isomorphism check so you could compare compare construct results.
Claude
On 9 Dec 2017 04:11, "Dan Davis" <[email protected]> wrote:
So, this is what I was asking about earlier. With small graphs, e.g.
DESCRIBE <....>, the algorithms for graph isomorphism that support blank
nodes should be good. rdflib includes an implementation, and I wish I
knew whether there is an implementation of that digest algorithm for Jena.
On Fri, Dec 8, 2017 at 2:27 AM, Claude Warren <[email protected]> wrote:
On Fri, Nov 24, 2017 at 12:19 PM, Laura Morales <[email protected]>
wrote:
What about simply deleting the old graph and loading the triples of
the
.nt file into the graph afterwards? I don't see any benefit of such a
"tool" - you could just write your own bash script for this if you
need
this quite often.
The advantage is with large graphs, such as wikidata. If I download
their
dumps once a week, it's much more efficient to only change a few
triples
instead of deleting the entire graph and recreating the whole TDB
store.
Performing a diff between two graphs with blank nodes might be speed up
using bloom filters.
I have code that represents triples as bloom filters and I know that 9
byte
filters will work for very large graphs so you could probably get aways
with 8 bytes to make them fit in a standard integer size.
This is a multiple pass operation.
create a bloom filter for each node in graph A. Call this list A
step through graph B creating bloom filters for each triple. if the
triple
in question has blank nodes only encode non blank nodes
If the bloom filter is not in List A it is new.
if the bloom filter is in list A then it may be new and a direct lookup
in
graph A. if it is not found add it
If your filter list has a pointer to the triples that it represents
(remember there can be bloom filter collisions) then you can rapidly
determine if there is a match and you also have a good starting place to
do
blank node comparisons to determine if the triples are equivalent.
If anyone is interested in trying this I have some triple/bloom filter
code
in my github repository.
Claude
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