com.bigdata.rdf.graph

Interface IStaticFrontier

All Superinterfaces:

Iterable<org.openrdf.model.Value>

All Known Implementing Classes:

StaticFrontier2

public interface IStaticFrontier
extends Iterable<org.openrdf.model.Value>

Interface abstracts the fixed frontier as known on entry into a new round.

Author:

Bryan Thompson

Method Summary

Methods

Modifier and Type	Method and Description
boolean	isCompact() Return true iff the frontier is known to be compact (no duplicate vertices).
boolean	isEmpty() Return true if the frontier is known to be empty.
void	resetFrontier(int minCapacity, boolean sort, Iterator<org.openrdf.model.Value> vertices) Reset the frontier from the supplied vertices.
int	size() The number of vertices in the frontier.

Methods inherited from interface java.lang.Iterable

iterator

Method Detail

size

int size()

The number of vertices in the frontier. TODO Long? Or just do not allow in scale-out?

isEmpty

boolean isEmpty()

Return true if the frontier is known to be empty.

isCompact

boolean isCompact()

Return true iff the frontier is known to be compact (no duplicate vertices).

Note: If the frontier is not compact, then the IGASEngine may optionally elect to eliminate duplicate work when it schedules the vertices in the frontier.

Note: A non-compact frontier can arise when the IGASScheduler chooses a per-thread approach and then copies the per-thread segments onto the shared backing array in parallel. This can reduce the time between rounds, which can speed up the overall execution of the algorithm significantly.

resetFrontier

void resetFrontier(int minCapacity,
                 boolean sort,
                 Iterator<org.openrdf.model.Value> vertices)

Reset the frontier from the supplied vertices.

Parameters:

minCapacity - The minimum capacity of the new frontier. (A minimum capacity is specified since many techniques to compact the frontier can only estimate the required capacity.)

ordered - true iff the vertices are not known to be ordered and SHOULD be ordered (some backends do not benefit from ordering the vertices).

vertices - The vertices in the new frontier.