diff options
author | Andrej Shadura <andrewsh@debian.org> | 2019-03-09 22:30:41 +0000 |
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committer | Andrej Shadura <andrewsh@debian.org> | 2019-03-09 22:30:41 +0000 |
commit | 38212b3127e90751fb39cda34250bc11be62b76c (patch) | |
tree | dc1397346030e9695bd763dddc93b3be527cd643 /elki/src/main/java/de/lmu/ifi/dbs/elki/database/ids/generic/KNNSubList.java | |
parent | 337087b668d3a54f3afee3a9adb597a32e9f7e94 (diff) |
Import Upstream version 0.7.0
Diffstat (limited to 'elki/src/main/java/de/lmu/ifi/dbs/elki/database/ids/generic/KNNSubList.java')
-rw-r--r-- | elki/src/main/java/de/lmu/ifi/dbs/elki/database/ids/generic/KNNSubList.java | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/elki/src/main/java/de/lmu/ifi/dbs/elki/database/ids/generic/KNNSubList.java b/elki/src/main/java/de/lmu/ifi/dbs/elki/database/ids/generic/KNNSubList.java new file mode 100644 index 00000000..1563efd4 --- /dev/null +++ b/elki/src/main/java/de/lmu/ifi/dbs/elki/database/ids/generic/KNNSubList.java @@ -0,0 +1,182 @@ +package de.lmu.ifi.dbs.elki.database.ids.generic; + +/* + This file is part of ELKI: + Environment for Developing KDD-Applications Supported by Index-Structures + + Copyright (C) 2015 + 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 de.lmu.ifi.dbs.elki.database.ids.DBIDIter; +import de.lmu.ifi.dbs.elki.database.ids.DBIDRef; +import de.lmu.ifi.dbs.elki.database.ids.DBIDUtil; +import de.lmu.ifi.dbs.elki.database.ids.DoubleDBIDListIter; +import de.lmu.ifi.dbs.elki.database.ids.DoubleDBIDPair; +import de.lmu.ifi.dbs.elki.database.ids.KNNList; + +/** + * Sublist of an existing result to contain only the first k elements. + * + * @author Erich Schubert + */ +public class KNNSubList implements KNNList { + /** + * Parameter k. + */ + private final int k; + + /** + * Actual size, including ties. + */ + private final int size; + + /** + * Wrapped inner result. + */ + private final KNNList inner; + + /** + * Constructor. + * + * @param inner Inner instance + * @param k k value + */ + public KNNSubList(KNNList inner, int k) { + this.inner = inner; + this.k = k; + // Compute list size + if(k < inner.getK()) { + DoubleDBIDPair dist = inner.get(k); + int i = k; + while(i + 1 < inner.size()) { + if(dist.doubleValue() < inner.get(i + 1).doubleValue()) { + break; + } + i++; + } + size = i; + } + else { + size = inner.size(); + } + } + + @Override + public int getK() { + return k; + } + + @Override + public DoubleDBIDPair get(int index) { + assert (index < size) : "Access beyond design size of list."; + return inner.get(index); + } + + @Override + public double getKNNDistance() { + return inner.get(k).doubleValue(); + } + + @Override + public DoubleDBIDListIter iter() { + return new Itr(); + } + + @Override + public boolean contains(DBIDRef o) { + for(DBIDIter iter = iter(); iter.valid(); iter.advance()) { + if(DBIDUtil.equal(iter, o)) { + return true; + } + } + return false; + } + + @Override + public boolean isEmpty() { + return size == 0; + } + + @Override + public int size() { + return size; + } + + /** + * Iterator for the sublist. + * + * @author Erich Schubert + * + * @apiviz.exclude + */ + private class Itr implements DoubleDBIDListIter { + /** + * Current position. + */ + private int pos = 0; + + @Override + public boolean valid() { + return pos < size && pos >= 0; + } + + @Override + public Itr advance() { + pos++; + return this; + } + + @Override + public double doubleValue() { + return inner.get(pos).doubleValue(); + } + + @Override + public DoubleDBIDPair getPair() { + return inner.get(pos); + } + + @Override + public int internalGetIndex() { + return inner.get(pos).internalGetIndex(); + } + + @Override + public int getOffset() { + return pos; + } + + @Override + public Itr advance(int count) { + pos += count; + return this; + } + + @Override + public Itr retract() { + --pos; + return this; + } + + @Override + public Itr seek(int off) { + pos = off; + return this; + } + } +} |