using System;

namespace BrazilTimestampReconstruction
{
	/// <summary>
	/// Returns the incomplete gamma function Q(a, x) = 1 -  P(a, x).
	/// </summary>
	public class Gammq
	{
		public Gammq()
		{
		}
		public double gammq(double a, double x)
		{
			Gcf cf = new Gcf();
	        Gser ser = new Gser();
	    	if (x < 0.0 || a <= 0.0) 
				try{throw new Exception();}
				catch (Exception)
				{
					
				}
	        if (x < (a+1.0)) 
			{
		        ser.gser(a,x);
                return 1.0-ser.Gamser;
	        }
			else 
			{
		        cf.gcf(a,x);
	        	return cf.Gammcf;
	        }
		}
	}
}
/*
        private void button1_Click(object sender, System.EventArgs e)
    	{
    		NR.SpecialFunctions.Gammq dd = new NR.SpecialFunctions.Gammq();
    		textBox1.Text = Convert.ToString(dd.gammq(10.5,2.0));
    	}
// result
0.999980128425815
*/