info.debatty.java.graphs.build

Class PartitioningGraphBuilder<T>

java.lang.Object

info.debatty.java.graphs.build.GraphBuilder<T>

info.debatty.java.graphs.build.PartitioningGraphBuilder<T>

Type Parameters:

T - The type of nodes value

All Implemented Interfaces:

Serializable, Cloneable

Direct Known Subclasses:

NNCTPH

public abstract class PartitioningGraphBuilder<T>
extends GraphBuilder<T>

Abstract class for graph building algorithms that split the dataset into partitions (for example using LSH). The number of stages (n_stages) and the number of partitions (n_partitions) allow you to control the speedup and precision. If brute-force method is used inside the partitions: number of similarities to compute ≃ n² / 2 x n_stages / n_partitions where n is the size of the dataset Thus speedup with respect to pure brute force ≃ n_partitions / n_stages At the same time: - increasing n_stages will increase the precision - increasing n_partitions will decrease the precision The exact relation between precision and these 2 parameters depends on the algorithm used...

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected GraphBuilder	internal_builder
protected int	n_partitions
protected int	oversampling

Fields inherited from class info.debatty.java.graphs.build.GraphBuilder

callback, computed_similarities, k, similarity

Constructor Summary

Constructors

Constructor and Description
PartitioningGraphBuilder()

Method Summary

Methods

Modifier and Type	Method and Description
protected Graph<T>	_computeGraph(List<Node<T>> nodes)
protected abstract List<Node<T>>[]	_partition(List<Node<T>> nodes)
double	estimatedSpeedup()
GraphBuilder	getInternalBuilder()
int	getNPartitions() Default = 4
int	getOversampling()
void	setInternalBuilder(GraphBuilder internal_builder) Default = Brute force
void	setNPartitions(int n_partitions) Set the number of partitions to build for each stage.
void	setOversampling(int oversampling) Default = 2

Methods inherited from class info.debatty.java.graphs.build.GraphBuilder

clone, computeGraph, getCallback, getComputedSimilarities, getK, getSimilarity, readFile, setCallback, setK, setSimilarity, test

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

oversampling

protected int oversampling

n_partitions

protected int n_partitions

internal_builder

protected GraphBuilder internal_builder

Constructor Detail

PartitioningGraphBuilder

public PartitioningGraphBuilder()

Method Detail

getOversampling

public int getOversampling()

setOversampling

public void setOversampling(int oversampling)

Default = 2

Parameters:

oversampling -

getNPartitions

public int getNPartitions()

Default = 4

Returns:

setNPartitions

public void setNPartitions(int n_partitions)

Set the number of partitions to build for each stage. Attention: the number of strings per partition should be at least 100 to get relevant results! Default = 4

Parameters:

n_partitions -

getInternalBuilder

public GraphBuilder getInternalBuilder()

setInternalBuilder

public void setInternalBuilder(GraphBuilder internal_builder)

Default = Brute force

Parameters:

internal_builder -

_computeGraph

protected Graph<T> _computeGraph(List<Node<T>> nodes)

Specified by:

_computeGraph in class GraphBuilder<T>

estimatedSpeedup

public double estimatedSpeedup()

Overrides:

estimatedSpeedup in class GraphBuilder<T>

_partition

protected abstract List<Node<T>>[] _partition(List<Node<T>> nodes)