package numbercruncher.mathutils;/** * The base class for differential equation solvers. */public abstract class DiffEqSolver{    /** the differential equation to solve */    protected DifferentialEquation equation;    /** the initial condition data point */    protected DataPoint initialCondition;    /** current x value */      protected float x;    /** current y value */      protected float y;    /**     * Constructor.     * @param equation the differential equation to solve     */    public DiffEqSolver(DifferentialEquation equation)    {        this.equation         = equation;        this.initialCondition = equation.getInitialCondition();        reset();    }    /**     * Reset x and y to the initial condition data point.     */    public void reset()    {        this.x = initialCondition.x;        this.y = initialCondition.y;    }    /**     * Return the next data point in the     * approximation of the solution.     * @param h the width of the interval     */    public abstract DataPoint nextPoint(float h);}