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Diffstat (limited to 'src/de/lmu/ifi/dbs/elki/datasource/filter/normalization/RankTieNormalization.java')
| -rw-r--r-- | src/de/lmu/ifi/dbs/elki/datasource/filter/normalization/RankTieNormalization.java | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/src/de/lmu/ifi/dbs/elki/datasource/filter/normalization/RankTieNormalization.java b/src/de/lmu/ifi/dbs/elki/datasource/filter/normalization/RankTieNormalization.java new file mode 100644 index 00000000..be8c1166 --- /dev/null +++ b/src/de/lmu/ifi/dbs/elki/datasource/filter/normalization/RankTieNormalization.java @@ -0,0 +1,113 @@ +package de.lmu.ifi.dbs.elki.datasource.filter.normalization; + +/* + This file is part of ELKI: + Environment for Developing KDD-Applications Supported by Index-Structures + + Copyright (C) 2012 + 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.ArrayList; +import java.util.Arrays; +import java.util.List; + +import de.lmu.ifi.dbs.elki.data.IntegerVector; +import de.lmu.ifi.dbs.elki.data.NumberVector; +import de.lmu.ifi.dbs.elki.data.type.SimpleTypeInformation; +import de.lmu.ifi.dbs.elki.data.type.TypeUtil; +import de.lmu.ifi.dbs.elki.data.type.VectorFieldTypeInformation; +import de.lmu.ifi.dbs.elki.datasource.bundle.MultipleObjectsBundle; +import de.lmu.ifi.dbs.elki.datasource.filter.ObjectFilter; +import de.lmu.ifi.dbs.elki.utilities.pairs.DoubleIntPair; + +/** + * Normalize vectors according to their rank in the attributes. + * + * Note: ranks are multiplied by 2, to be able to give ties an integer rank. + * (e.g. first two records are tied at "1" then, followed by the next on "4") + * + * @author Erich Schubert + */ +public class RankTieNormalization implements ObjectFilter { + /** + * Constructor. + */ + public RankTieNormalization() { + super(); + } + + @Override + public MultipleObjectsBundle filter(MultipleObjectsBundle objects) { + final int len = objects.dataLength(); + MultipleObjectsBundle bundle = new MultipleObjectsBundle(); + + for(int r = 0; r < objects.metaLength(); r++) { + final SimpleTypeInformation<?> type = objects.meta(r); + final List<?> column = objects.getColumn(r); + if(!TypeUtil.NUMBER_VECTOR_FIELD.isAssignableFromType(type)) { + bundle.appendColumn(type, column); + continue; + } + @SuppressWarnings("unchecked") + final List<? extends NumberVector<?, ?>> castColumn = (List<? extends NumberVector<?, ?>>) column; + // Get the replacement type information + final int dim = ((VectorFieldTypeInformation<?>) type).dimensionality(); + final VectorFieldTypeInformation<IntegerVector> outType = new VectorFieldTypeInformation<IntegerVector>(IntegerVector.class, dim, IntegerVector.STATIC); + + // Output vectors + int[][] posvecs = new int[len][dim]; + // Sort for each dimension + // TODO: an int[] array would be enough, if we could use a comparator... + DoubleIntPair[] sorter = new DoubleIntPair[len]; + for(int i = 0; i < sorter.length; i++) { + sorter[i] = new DoubleIntPair(Double.NaN, -1); + } + for(int d = 1; d <= dim; d++) { + // fill array + for(int i = 0; i < sorter.length; i++) { + sorter[i].first = castColumn.get(i).doubleValue(d); + sorter[i].second = i; + } + // Sort + Arrays.sort(sorter); + // Transfer positions to output vectors + for(int sta = 0; sta < sorter.length;) { + // Compute ties + int end = sta + 1; + while(end < sorter.length && sorter[sta].first == sorter[end].first) { + end++; + } + final int pos = (sta + end - 1); + for(int i = sta; i < end; i++) { + posvecs[sorter[i].second][d - 1] = pos; + } + sta = end; + } + } + + // Prepare output data + final List<IntegerVector> outColumn = new ArrayList<IntegerVector>(len); + for(int i = 0; i < len; i++) { + outColumn.add(new IntegerVector(posvecs[i])); + } + bundle.appendColumn(outType, outColumn); + } + return bundle; + } +}
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