teichmann@5831: package org.dive4elements.river.artifacts.math.fitting;
sascha@2569: 
sascha@2569: public class Linear
sascha@2569: extends      Function
sascha@2569: {
sascha@3009:     public static final Derivative DERIVATIVE =
sascha@3009:         new Derivative("W'(Q) = m") {
sascha@3009: 
sascha@3009:         @Override
teichmann@5831:         public org.dive4elements.river.artifacts.math.Function
sascha@3009:             instantiate(double [] parameters)
sascha@3009:         {
sascha@3009:             final double m = parameters[0];
sascha@3009: 
teichmann@5831:             return new org.dive4elements.river.artifacts.math.Function() {
sascha@3009:                 @Override
sascha@3009:                 public double value(double Q) {
sascha@3009:                     return m;
sascha@3009:                 }
sascha@3009:             };
sascha@3009:         }
sascha@3009:     };
sascha@3009: 
sascha@3177:     public static final Function INSTANCE = new Linear();
sascha@3177: 
sascha@2569:     public Linear() {
sascha@2569:         super("linear", "W(Q) = m*Q + b", new String [] { "m", "b" });
sascha@2569:     }
sascha@2569: 
sascha@2569:     @Override
sascha@2569:     public double value(double x, double [] parameters) {
sascha@2569:         return x*parameters[0] + parameters[1];
sascha@2569:     }
sascha@2569: 
sascha@2569:     @Override
sascha@2569:     public double [] gradient(double x, double [] parameters) {
sascha@2569:         return new double [] { x, 1d };
sascha@2569:     }
sascha@3009: 
sascha@3009:     @Override
sascha@3009:     public Derivative getDerivative() {
sascha@3009:         return DERIVATIVE;
sascha@3009:     }
sascha@3177: 
sascha@3177:     @Override
sascha@3177:     public Function getInverse() {
sascha@3177:         return InvLinear.INSTANCE;
sascha@3177:     }
sascha@2569: }
sascha@2569: // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :