package sansmodels;

public class TeubnerStrey extends SANSModel{
 
    private double scale, coeff1, coeff2, background;

    //Default constructor
    public TeubnerStrey() {
        scale = 0.1;
        coeff1 = -30.;
        coeff2 = 5000.;
        background = 0.0;
        setNumberOfParameters(4);
        String[] parameters = {"Scale", "Coeff 1",
            "Coeff 2", "Background (cm-1)"};
        setParametersText(parameters);
    }

    public TeubnerStrey(double inScale, double inCoeff1, double inCoeff2,
                  double inBackground) {
        scale = inScale; 
        coeff1 = inCoeff1;
        coeff2 = inCoeff2;
        background = inBackground;
        setNumberOfParameters(4);
        String[] parameters = {"Scale", "Coeff 1",
            "Coeff 2", "Background (cm-1)"};
        setParametersText(parameters);
    }

    public double getFormFactor(double inX) {
        double q2,q4;
        
        q2 = inX*inX;
        q4 = q2*q2;
        return 1.0/(scale + coeff1*q2 + coeff2*q4)
            *getStructureFactor().calculate(inX) + background;
    }


    public void setParameters(double[] inParameters) {
        scale = inParameters[0];
        coeff1 = inParameters[1];
        coeff2 = inParameters[2];
        background = inParameters[3];
    }
 
    public double[] getParameters() {
        double[] outParameters = new double[4];
        outParameters[0] = scale;
        outParameters[1] = coeff1;
        outParameters[2] = coeff2;
        outParameters[3] = background;
        return outParameters;
    }
}