001 /* 002 * Copyright (C) 2008-2010 by Holger Arndt 003 * 004 * This file is part of the Universal Java Matrix Package (UJMP). 005 * See the NOTICE file distributed with this work for additional 006 * information regarding copyright ownership and licensing. 007 * 008 * UJMP is free software; you can redistribute it and/or modify 009 * it under the terms of the GNU Lesser General Public License as 010 * published by the Free Software Foundation; either version 2 011 * of the License, or (at your option) any later version. 012 * 013 * UJMP is distributed in the hope that it will be useful, 014 * but WITHOUT ANY WARRANTY; without even the implied warranty of 015 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 016 * GNU Lesser General Public License for more details. 017 * 018 * You should have received a copy of the GNU Lesser General Public 019 * License along with UJMP; if not, write to the 020 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, 021 * Boston, MA 02110-1301 USA 022 */ 023 024 package org.ujmp.core.doublematrix.calculation.general.missingvalues; 025 026 import java.util.ArrayList; 027 import java.util.Collections; 028 import java.util.List; 029 030 import org.ujmp.core.Matrix; 031 import org.ujmp.core.doublematrix.calculation.AbstractDoubleCalculation; 032 import org.ujmp.core.exceptions.MatrixException; 033 import org.ujmp.core.util.MathUtil; 034 import org.ujmp.core.util.Sortable; 035 036 public class ImputeKNN extends AbstractDoubleCalculation { 037 private static final long serialVersionUID = -4923873199518001578L; 038 039 private Matrix distanceMatrix = null; 040 041 private int k = 1; 042 043 public ImputeKNN(Matrix matrix, Object... parameters) { 044 super(matrix); 045 if (parameters.length != 0) { 046 k = MathUtil.getInt(parameters[0]); 047 } 048 } 049 050 private List<Integer> getCandidates(long... coordinates) { 051 List<Integer> candidates = new ArrayList<Integer>(); 052 for (int r = 0; r < getSource().getRowCount(); r++) { 053 if (coordinates[ROW] == r) { 054 continue; 055 } 056 if (!MathUtil.isNaNOrInfinite(getSource().getAsDouble(r, coordinates[COLUMN]))) { 057 candidates.add(r); 058 } 059 } 060 return candidates; 061 } 062 063 private Matrix getDistanceMatrix() { 064 Matrix distanceMatrix = Matrix.factory.zeros(getSource().getRowCount(), getSource() 065 .getRowCount()); 066 for (int r = 0; r < getSource().getRowCount(); r++) { 067 for (int c = 0; c < getSource().getRowCount(); c++) { 068 if (r != c) { 069 Matrix m1 = getSource().selectRows(Ret.LINK, r); 070 Matrix m2 = getSource().selectRows(Ret.LINK, c); 071 double dist = m1.euklideanDistanceTo(m2, true); 072 distanceMatrix.setAsDouble(dist, r, c); 073 } 074 } 075 } 076 return distanceMatrix; 077 } 078 079 private List<Sortable<Double, Matrix>> getSortedNeighbors(long... coordinates) { 080 List<Sortable<Double, Matrix>> neighbors = new ArrayList<Sortable<Double, Matrix>>(); 081 List<Integer> candidates = getCandidates(coordinates); 082 083 for (int candidateRow : candidates) { 084 double dist = distanceMatrix.getAsDouble(coordinates[ROW], candidateRow); 085 Matrix candidate = getSource().selectRows(Ret.LINK, candidateRow); 086 neighbors.add(new Sortable<Double, Matrix>(dist, candidate)); 087 } 088 089 Collections.sort(neighbors); 090 return neighbors; 091 } 092 093 public double getDouble(long... coordinates) throws MatrixException { 094 if (distanceMatrix == null) { 095 distanceMatrix = getDistanceMatrix(); 096 } 097 double value = getSource().getAsDouble(coordinates); 098 if (MathUtil.isNaNOrInfinite(value)) { 099 List<Sortable<Double, Matrix>> sortedNeighbors = getSortedNeighbors(coordinates); 100 double sum = 0; 101 int count = 0; 102 for (Sortable<Double, Matrix> s : sortedNeighbors) { 103 sum += s.getObject().getAsDouble(0, coordinates[COLUMN]); 104 if (++count == k) { 105 break; 106 } 107 } 108 return sum / count; 109 } else { 110 return value; 111 } 112 } 113 114 }