Merged revisions 5501-5502,5504-5508,5511-5513,5516-5519 via svnmerge from file:///home/clients/bsh/bsh-generischer-viewer/Material/SVN/flys-artifacts/trunk ........ r5501 | felix | 2012-09-18 11:49:45 +0200 (Di, 18 Sep 2012) | 1 line fix issue865 - missing showarea theme prop. ........ r5502 | clins | 2012-09-18 12:18:30 +0200 (Di, 18 Sep 2012) | 1 line Add robustness checks to prevent NPEs ........ r5504 | felix | 2012-09-18 14:03:15 +0200 (Di, 18 Sep 2012) | 1 line i18n for area label (fix issue487). ........ r5505 | clins | 2012-09-18 16:19:59 +0200 (Di, 18 Sep 2012) | 1 line Update themes to show point descriptions ........ r5506 | rrenkert | 2012-09-18 17:00:30 +0200 (Di, 18 Sep 2012) | 3 lines Removed incorrect characteristic diameter. ........ r5507 | rrenkert | 2012-09-18 17:03:20 +0200 (Di, 18 Sep 2012) | 3 lines Fixed some stupid bugs in bed quality data factory and calculation. ........ r5508 | teichmann | 2012-09-18 17:45:49 +0200 (Di, 18 Sep 2012) | 1 line The usual whitespace and import cleanups. ........ r5511 | teichmann | 2012-09-18 18:24:51 +0200 (Di, 18 Sep 2012) | 1 line Use generics aware Collections.emptyList(). ........ r5512 | teichmann | 2012-09-18 20:36:52 +0200 (Di, 18 Sep 2012) | 1 line Some more little steps towards "Auslagerung extremer Wasserspiegellagen". ........ r5513 | clins | 2012-09-18 23:38:19 +0200 (Di, 18 Sep 2012) | 1 line A and B facets of fix analyis are now deactivated by default ........ r5516 | bricks | 2012-09-19 10:45:51 +0200 (Mi, 19 Sep 2012) | 2 lines Add the gauge station to the GaugeOverviewInfoService xml response ........ r5517 | rrenkert | 2012-09-19 10:50:23 +0200 (Mi, 19 Sep 2012) | 3 lines Added CSV export to bed quality calculation. ........ r5518 | bricks | 2012-09-19 11:04:04 +0200 (Mi, 19 Sep 2012) | 2 lines Fix date in changelog entry ........ r5519 | teichmann | 2012-09-19 11:17:14 +0200 (Mi, 19 Sep 2012) | 1 line Removed trailing whitespace. ........ flys-artifacts/tags/2.9.1@5531 c6561f87-3c4e-4783-a992-168aeb5c3f6f

package de.intevation.flys.artifacts.math.fitting;

public class Log
extends      Function
{
    public static final Derivative DERIVATIVE =
        new Derivative("W'(Q) = m/(Q+b)") {

        @Override
        public de.intevation.flys.artifacts.math.Function
            instantiate(double [] parameters)
        {
            final double m = parameters[0];
            final double b = parameters[1];

            return new de.intevation.flys.artifacts.math.Function() {
                @Override
                public double value(double Q) {
                    return m/(Q+b);
                }
            };
        }
    };

    public static final Function INSTANCE = new Log();

    public Log() {
        super("log",  "W(Q) = m*ln(Q + b)", new String [] { "m", "b" });
    }

    @Override
    public double value(double x, double [] parameters) {
        return parameters[0]*Math.log(x + parameters[1]);
    }

    @Override
    public double [] gradient(double x, double [] parameters) {
        double m = parameters[0];
        double b = parameters[1];
        double b_x = b + x;
        return new double [] {
            Math.log(b_x),
            m/b_x
        };
    }

    @Override
    public Derivative getDerivative() {
        return DERIVATIVE;
    }

    @Override
    public Function getInverse() {
        return InvLog.INSTANCE;
    }
}
// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :