On 16/01/2012 21:05, Dave Reynolds wrote:
On 16/01/12 11:42, Marcus Cobden wrote:
I've loaded a TRIG graph using ng4j, but I am finding that reasoning
over it is particularly slow.
After converting the same graph to N-Triples, and working with only jena
models the reasoning is a lot faster.
Underneath, ng4j is using a MultiUnion graph to combine the named
graphs, would this be causing some slowness?
Possibly. A reasoner will ask a lot of find operations and for MultiUnion each
find will be distributed to each graph which does entail some overhead. If
there is any redundancy between the graphs then there could be duplicated
traversals.
You could test if it is MultiUnion or some other aspect of ng4j by converting
the data to an OntModel instead with addSubModel to add each graph.
It looks like it's not something ng4j specific:
Pre-flattened n-triples:
~17.14s
ng4j:
~395.08s
ont-model:
~313.46s
I'm running over the BSBM dataset, split into graphs. There are 29355 triples
before inference, and 40359 after.
This is roughly what my code is doing:
OntModel om = ModelFactory.createOntologyModel(OntModelSpec.RDFS_MEM);
// Add a bunch of submodels read from the filesystem.
//Model m = ModelFactory.createDefaultModel();
//om.addSubModel(m);
Assert.assertEquals(29355, om.size());
Resource config = ModelFactory.createDefaultModel()
.createResource()
.addProperty(ReasonerVocabulary.PROPsetRDFSLevel,
RDFSRuleReasoner.FULL_RULES);
Reasoner reasoner =
RDFSRuleReasonerFactory.theInstance().create(config);
reasoner.setDerivationLogging(true);
InfModel infm = ModelFactory.createInfModel(reasoner, om);
Assert.assertEquals(40359, infm.size());
Do you have any other suggestions?
