package sansmodels;

public class PeakGauss extends SANSModel{
 
    private double scale, peak, width, background;

    //Default constructor
    public PeakGauss() {
        scale = 100.0;
        peak = 0.05;
        width = 0.005;
        background = 0.0;
        setNumberOfParameters(4);
        String[] parameters = {"Scale", "Peak Position (A-1)",
            "Std Dev (A-1)","Background (cm-1)"};
        setParametersText(parameters);
    }

    public PeakGauss(double inScale, double inPeak, double inWidth,
                  double inBackground) {
        scale = inScale; 
        peak = inPeak;
        width = inWidth;
        background = inBackground;
        setNumberOfParameters(4);
        String[] parameters = {"Scale", "Peak Position (A-1)",
            "Peak HWHM (A-1)","Background (cm-1)"};
        setParametersText(parameters);
    }

    public double getFormFactor(double inX) {
        return scale*Math.exp(-0.5*(inX-peak)*(inX-peak)/width/width) 
            *getStructureFactor().calculate(inX) + background;
    }

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