org.aksw.limes.core.measures.measure.space

Class BlockIdGenerator

java.lang.Object

org.aksw.limes.core.measures.measure.space.BlockIdGenerator

public class BlockIdGenerator
extends Object

Version:

Jul 16, 2016

Author:

Axel-C. Ngonga Ngomo (ngonga@informatik.uni-leipzig.de), Mohamed Sherif (sherif@informatik.uni-leipzig.de)

Constructor Summary

Constructors

Constructor and Description
BlockIdGenerator(String props, String measureName, double threshold) Initializes the generator.

Method Summary

Modifier and Type	Method and Description
ArrayList<Integer>	getBlockId(Instance a) Computes the block ID for a given instance a.
static ArrayList<ArrayList<Integer>>	getBlocksToCompare(ArrayList<Integer> blockId) Computes the ids of all the blocks surrounding a given block for comparison Will be extremely useful for parallelizing as we can use blocking on T and S as then put use locality

Methods inherited from class java.lang.Object

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

Constructor Detail

BlockIdGenerator

public BlockIdGenerator(String props,
                        String measureName,
                        double threshold)

Initializes the generator. The basic idea here is the following: First, pick a random instance origin. That is the center upon which the block ids will be computed. Each measure can return the threshold for blocking that is equivalent to the similarity threshold given in by the user. For euclidean metrics, this value is the same. Yet, for metrics that squeeze space, this might not be the case. It is important to notice that the generation assumes that the size of props.split("|") is the same as dimensions.

Parameters:

props - List of properties that make up each dimension

measureName - Name of the measure to be used to compute the similarity of instances

threshold - General similarity threshold for blocking

Method Detail

getBlocksToCompare

public static ArrayList<ArrayList<Integer>> getBlocksToCompare(ArrayList<Integer> blockId)

Computes the ids of all the blocks surrounding a given block for comparison Will be extremely useful for parallelizing as we can use blocking on T and S as then put use locality

Parameters:

blockId -

Returns:

the ids of all the blocks surrounding a given block for comparison

getBlockId

public ArrayList<Integer> getBlockId(Instance a)

Computes the block ID for a given instance a. The idea behind the blocking is to tile the target space into blocks of dimension thresdhold^dimensions. Each instance s from the source space is then compared with the blocks lying directly around s's block and the block where s is.

Parameters:

a - The instance whose blockId is to be computed

Returns:

The ID for the block of a