Merged revisions 2127-2133,2136-2137,2140,2143-2144,2146,2150-2151,2153-2154 via svnmerge from svn+ssh://teichmann@thoe/home/projects/Geospatial/bsh-generischer-viewer/Material/SVN/flys-artifacts/branches/facets-slt ........ r2127 | ingo | 2011-06-16 09:50:56 +0200 (Do, 16 Jun 2011) | 1 line Added a compute() method to WINFOArtifact which acts as a dispatcher for different computations. It triggers a calculation based on ComputeCallbacks that are generated by the current states. ........ r2128 | ingo | 2011-06-16 10:25:06 +0200 (Do, 16 Jun 2011) | 1 line Moved Waterlevel state into the correct package. ........ r2129 | ingo | 2011-06-16 10:43:58 +0200 (Do, 16 Jun 2011) | 1 line Added two more compute() methods to ComputeCallback to distinguish between different phases of the artifact. ........ r2130 | ingo | 2011-06-16 10:57:05 +0200 (Do, 16 Jun 2011) | 1 line Use enums to dispatch computeFeed() and computeAdvance(). ........ r2131 | ingo | 2011-06-16 11:04:59 +0200 (Do, 16 Jun 2011) | 1 line Store facets for each state. ........ r2132 | ingo | 2011-06-16 12:05:44 +0200 (Do, 16 Jun 2011) | 1 line Generated facets for each output aspect. ........ r2133 | ingo | 2011-06-16 15:24:00 +0200 (Do, 16 Jun 2011) | 1 line Write computed facets into artifacts describe document. ........ r2136 | ingo | 2011-06-16 16:10:49 +0200 (Do, 16 Jun 2011) | 1 line Add index and description of facets to collections describe document. ........ r2137 | ingo | 2011-06-16 16:31:41 +0200 (Do, 16 Jun 2011) | 1 line OutGenerators doOut() takes a facet object now instead of just its name. ........ r2140 | ingo | 2011-06-17 11:19:43 +0200 (Fr, 17 Jun 2011) | 1 line OutGenerators use now facets to fetch necessary data. ........ r2143 | teichmann | 2011-06-17 12:40:54 +0200 (Fr, 17 Jun 2011) | 1 line Removed ComputeCallback because this was thought too complicated. Fixed issue with facets not be re-generated if same state is entered again. ........ r2144 | teichmann | 2011-06-17 13:08:31 +0200 (Fr, 17 Jun 2011) | 1 line make getGauges() more robust ........ r2146 | teichmann | 2011-06-17 13:23:57 +0200 (Fr, 17 Jun 2011) | 1 line mico opt: inter cmps are faster than str cmps. ........ r2150 | teichmann | 2011-06-17 15:10:20 +0200 (Fr, 17 Jun 2011) | 1 line call computeAdvance() if we want to advance. ........ r2151 | teichmann | 2011-06-17 15:45:50 +0200 (Fr, 17 Jun 2011) | 1 line Base WST/CSV exports on facets. TODO: generate the facets. ........ r2153 | teichmann | 2011-06-17 16:03:29 +0200 (Fr, 17 Jun 2011) | 1 line Add facet to access raw computed data. ........ r2154 | teichmann | 2011-06-17 16:37:09 +0200 (Fr, 17 Jun 2011) | 1 line Generate data facets for the computed states. ........ flys-artifacts/trunk@2156 c6561f87-3c4e-4783-a992-168aeb5c3f6f

package de.intevation.flys.artifacts.math;

public final class Linear 
implements         Function
{
    private double m;
    private double b;

    public Linear(
        double x1, double x2,
        double y1, double y2
    ) {
        // y1 = m*x1 + b
        // y2 = m*x2 + b
        // y2 - y1 = m*(x2 - x1)
        // m = (y2 - y1)/(x2 - x1) # x2 != x1
        // b = y1 - m*x1

        if (x1 == x2) {
            m = 0;
            b = 0.5*(y1 + y2);
        }
        else {
            m = (y2 - y1)/(x2 - x1);
            b = y1 - m*x1;
        }
    }

    public static final double linear(
        double x,
        double x1, double x2,
        double y1, double y2
    ) {
        // y1 = m*x1 + b
        // y2 = m*x2 + b
        // y2 - y1 = m*(x2 - x1)
        // m = (y2 - y1)/(x2 - x1) # x2 != x1
        // b = y1 - m*x1

        if (x1 == x2) {
            return 0.5*(y1 + y2);
        }
        double m = (y2 - y1)/(x2 - x1);
        double b = y1 - m*x1;
        return x*m + b;
    }

    @Override
    public double value(double x) {
        return m*x + b;
    }

    public static final double factor(double x, double p1, double p2) {
        // 0 = m*p1 + b <=> b = -m*p1
        // 1 = m*p2 + b
        // 1 = m*(p2 - p1)
        // m = 1/(p2 - p1) # p1 != p2
        // f(x) = x/(p2-p1) - p1/(p2-p1) <=> (x-p1)/(p2-p1)

        return p1 == p2 ? 0.0 : (x-p1)/(p2-p1);
    }

    public static final double weight(double factor, double a, double b) {
        //return (1.0-factor)*a + factor*b;
        return a + factor*(b-a);
    }
}
// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :