package sansmodels;

public class PolyRectSphere extends SANSModel{
 
    private double scale, polyDisp, radius, deltaRho, background;

    //Default constructor
    public PolyRectSphere() {
        scale = 1.0;
        radius = 60.0;
        polyDisp = 0.12;
        deltaRho = 3.e-6;
        background = 0.0;
        setNumberOfParameters(5);
        String[] parameters = {"Scale", "Radius (A)",
            "Polydispersity (0-1)", "Contrast (A-2)", "Background (cm-1)"};
        setParametersText(parameters);
    }

    public PolyRectSphere(double inScale, double inRadius, 
                          double inPolyDisp,
                          double inDeltaRho, double inBackground) {
        scale = inScale; 
        radius = inRadius; 
        polyDisp = inPolyDisp;
        deltaRho = inDeltaRho;
        background = inBackground;
        setNumberOfParameters(5);
        String[] parameters = {"Scale", "Radius (A)",
            "Polydispersity (0-1)", "Contrast (A-2)", "Background (cm-1)"};
        setParametersText(parameters);
    }

    public double getFormFactor(double inX) {
        double inten,h1,qw,qr,width,sig,averad3;
       
        if (polyDisp <= 0.0) polyDisp = 0.0001;
        if (polyDisp >= 1.0) polyDisp = 1.0;
        sig = polyDisp*radius;
        width = Math.sqrt(3.0)*sig;

        qw = inX*width;
        qr = inX*radius;
        h1 = -0.5*qw + qr*qr*qw + qw*qw*qw/3.;
        h1 -= 5./2.*Math.cos(2.*qr)*Math.sin(qw)*Math.cos(qw);
        h1 += 0.5*qr*qr*Math.cos(2.*qr)*Math.sin(2.*qw);
        h1 += 0.5*qw*qw*Math.cos(2.*qr)*Math.sin(2.*qw);
        h1 += qw*qr*Math.sin(2.*qr)*Math.cos(2.*qw);
        h1 += 3.*qw*Math.cos(qr)*Math.cos(qw)*Math.cos(qr)*Math.cos(qw);
        h1 += 3.*qw*Math.sin(qr)*Math.sin(qw)*Math.sin(qr)*Math.sin(qw);
        h1 -= 6.*qr*Math.cos(qr)*Math.sin(qr)*Math.cos(qw)*Math.sin(qw);
 
 
        inten = 8.*Math.PI*Math.PI*deltaRho*deltaRho/width/Math.pow(inX,7.0)*h1;
 
        averad3 =  radius*radius*radius*(1.+3.*polyDisp*polyDisp);
        inten /= 4.*Math.PI/3.*averad3;
 
        return inten*1.0e8*scale*getStructureFactor().calculate(inX) 
            + background;
    }


    public void setParameters(double[] inParameters) {
        scale = inParameters[0];
        radius = inParameters[1];
        polyDisp = inParameters[2];
        deltaRho = inParameters[3];
        background = inParameters[4];
    }
 
    public double[] getParameters() {
        double[] outParameters = new double[5];
        outParameters[0] = scale;
        outParameters[1] = radius;
        outParameters[2] = polyDisp;
        outParameters[3] = deltaRho;
        outParameters[4] = background;
        return outParameters;
    }
}