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.entrywise.misc;
025    
026    import org.ujmp.core.Matrix;
027    import org.ujmp.core.doublematrix.calculation.AbstractDoubleCalculation;
028    import org.ujmp.core.exceptions.MatrixException;
029    
030    public class LogisticFunction extends AbstractDoubleCalculation {
031            private static final long serialVersionUID = -82780095324379021L;
032    
033            public LogisticFunction(Matrix matrix) {
034                    super(matrix);
035            }
036    
037            
038            public double getDouble(long... coordinates) throws MatrixException {
039                    return 1.0 / (Math.exp(-getSource().getAsDouble(coordinates)) + 1);
040            }
041    
042    }