package sansmodels;

public class Lorentz extends SANSModel{
 
    private double scale, length, background;

    //Default constructor
    public Lorentz() {
        scale = 100.0;
        length = 50.0;
        background = 0.0;
        setNumberOfParameters(3);
        String[] parameters = {"Scale", "Screening Length (A)",
            "Background (cm-1)"};
        setParametersText(parameters);
    }

    public Lorentz(double inScale, double inLength,
                  double inBackground) {
        scale = inScale; 
        length = inLength;
        background = inBackground;
        setNumberOfParameters(3);
        String[] parameters = {"Scale", "Screening Length (A)",
            "Background (cm-1)"};
        setParametersText(parameters);
    }

    public double getFormFactor(double inX) {
        return scale/(1.0+ inX*inX*length*length)
            *getStructureFactor().calculate(inX) + background;
    }

    public void setParameters(double[] inParameters) {
        scale = inParameters[0];
        length = inParameters[1];
        background = inParameters[2];
    }
 
    public double[] getParameters() {
        double[] outParameters = new double[3];
        outParameters[0] = scale;
        outParameters[1] = length;
        outParameters[2] = background;
        return outParameters;
    }
}