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.mtj.calculation;
025    
026    import no.uib.cipr.matrix.DenseMatrix;
027    import no.uib.cipr.matrix.Matrices;
028    
029    import org.ujmp.core.Coordinates;
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.mtj.MTJDenseDoubleMatrix2D;
034    
035    public class Inv extends AbstractDoubleCalculation {
036            private static final long serialVersionUID = 1441735603598847485L;
037    
038            private Matrix inv = null;
039    
040            public Inv(Matrix matrix) {
041                    super(matrix);
042            }
043    
044            public double getDouble(long... coordinates) throws MatrixException {
045                    if (inv == null) {
046                            DenseMatrix A = new MTJDenseDoubleMatrix2D(getSource())
047                                            .getWrappedObject();
048                            DenseMatrix I = Matrices.identity((int) getSource()
049                                            .getColumnCount());
050                            DenseMatrix AI = I.copy();
051                            inv = new MTJDenseDoubleMatrix2D((DenseMatrix) A.solve(I, AI));
052                    }
053                    return inv.getAsDouble(coordinates);
054            }
055    
056            public long[] getSize() {
057                    return Coordinates.transpose(getSource().getSize());
058            }
059    }