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.misc;
025    
026    import org.ujmp.core.Matrix;
027    import org.ujmp.core.matrix.SparseMatrix;
028    
029    public class Dense2Sparse {
030    
031            public static Matrix calc(Matrix indices) {
032                    Matrix m = SparseMatrix.factory.zeros(1, 1);
033    
034                    long mrow = 1;
035                    long mcol = 1;
036    
037                    for (int r = 0; r < indices.getRowCount(); r++) {
038    
039                            if (r % 1000 == 0) {
040                                    System.out.println("Row: " + r);
041                            }
042    
043                            long row = (long) indices.getAsDouble(r, 0);
044                            long col = (long) indices.getAsDouble(r, 1);
045                            double val = indices.getAsDouble(r, 2);
046    
047                            if (row >= mrow) {
048                                    mrow = row + 1;
049                                    m.setSize(mrow, mcol);
050                            }
051    
052                            if (col >= mcol) {
053                                    mcol = col + 1;
054                                    m.setSize(mrow, mcol);
055                            }
056    
057                            m.setAsDouble(val, row, col);
058    
059                    }
060    
061                    return m;
062            }
063    
064    }