void chsone(double bins[], double ebins[], int nbins, int knstrn,
			double& df, double& chsq, double& prob)
{
    df = double(nbins - 1 - knstrn);
    chsq = 0.0;
    for (int j = 1; j<=nbins; j++)
	{
        if (ebins[j] <= 0.0)
		{
            cout<<" bad expected number"<<endl;
            return;
        }
        chsq=chsq+(bins[j]-ebins[j])*(bins[j]-ebins[j])/ebins[j];
    }
    prob = gammq(0.5 * df, 0.5 * chsq);
}