package de.lmu.ifi.dbs.elki.evaluation.paircounting.generator;
/*
This file is part of ELKI:
Environment for Developing KDD-Applications Supported by Index-Structures
Copyright (C) 2011
Ludwig-Maximilians-Universität München
Lehr- und Forschungseinheit für Datenbanksysteme
ELKI Development Team
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
import java.util.Arrays;
import de.lmu.ifi.dbs.elki.data.Cluster;
import de.lmu.ifi.dbs.elki.database.ids.DBID;
import de.lmu.ifi.dbs.elki.database.ids.DBIDs;
import de.lmu.ifi.dbs.elki.utilities.pairs.IntIntPair;
/**
* Generator for noise points.
*
* This generator will generate pairs (a,a) for all elements a in the given
* list.
*
* @author Erich Schubert
*/
public class PairGeneratorNoise extends PairSortedGenerator {
/**
* Ids to use
*/
private int[] ids;
/**
* Current position.
*/
private int pos;
/**
* Crate new generator for a base cluster object.
*
* @param cluster object
*/
public PairGeneratorNoise(Cluster<?> cluster) {
// build int array for the cluster
// TODO: copy less.
DBIDs dbids = cluster.getIDs();
ids = new int[dbids.size()];
int j = 0;
for (DBID id : dbids) {
ids[j] = id.getIntegerID();
j++;
}
Arrays.sort(ids);
pos = 0;
if(ids.length > 0) {
setCurrent(new IntIntPair(ids[pos], ids[pos]));
}
}
/**
* Advance iterator and return new pair.
*/
@Override
protected IntIntPair advance() {
if(current() == null) {
return null;
}
pos++;
if(pos >= ids.length) {
return null;
}
else {
return new IntIntPair(ids[pos], ids[pos]);
}
}
}