Example #1
0
        public static X GetMin(Function f, X x, double Lambda, double eps)
        {
            int k = 0;

            Console.WriteLine(new String('-', 84));
            Console.WriteLine("{0,55}{1,30}", "Fast Gradient Descent", "|");
            Console.WriteLine(new String('-', 84) + "|");
            Console.WriteLine(
                "{0,3} |{1,20} |{2,10} |{3,10} |{4,20} |{5,10} |",
                "k", "x", "y", "Lambda", "G", "Norma");
            Console.WriteLine(
                "{0}{2}{1}{1}{2}{1}",
                "----|", "-----------|", "---------------------|");
            while (f.Norma(x) > eps)
            {
                Console.WriteLine(
                    "{0,3} |{1,20} |{2,10:0.0000} |{3,10:0.00} |{4,20} |{5,10:0.000} |",
                    k, x, f.F(x), Lambda, new X(f.Fdx1(x), f.Fdx2(x)), f.Norma(x));
                Lambda = Dichotomy.GetMin((lambda) => f.F(new X(x.X1 - lambda * f.Fdx1(x), x.X2 - lambda * f.Fdx2(x))), -100, 100, 0.1);
                x      = new X(x.X1 - Lambda * f.Fdx1(x), x.X2 - Lambda * f.Fdx2(x));
                k++;
            }
            Console.WriteLine(new String('-', 84));
            return(x);
        }
        public static X GetMin(Function f, X x0, double Lambda, double eps)
        {
            X      x      = x0;
            X      x_prev = x;
            int    k      = 0;
            X      d      = new X(0, 0);
            double Betta  = 0;

            Console.WriteLine(new String('-', 84));
            Console.WriteLine("{0,55}{1,30}", "Nonlinear Conjugate Dradient Method", "|");
            Console.WriteLine(new String('-', 84) + "|");
            Console.WriteLine(
                "{0,3} |{1,20} |{2,10} |{3,10} |{4,20} |{5,10} |",
                "k", "x", "y", "Lambda", "G", "Norma");
            Console.WriteLine(
                "{0}{2}{1}{1}{2}{1}",
                "----|", "-----------|", "---------------------|");
            while (f.Norma(x) > eps)
            {
                Console.WriteLine(
                    "{0,3} |{1,20} |{2,10:0.0000} |{3,10:0.00} |{4,20} |{5,10:0.000} |",
                    k, x, f.F(x), Lambda, new X(f.Fdx1(x), f.Fdx2(x)), f.Norma(x));
                if (k == 0)
                {
                    //5
                    d = new X(-f.Fdx1(x0), -f.Fdx2(x0));
                }
                else
                {
                    {
                        Betta = Math.Pow(f.Norma(x), 2) / Math.Pow(f.Norma(x_prev), 2);
                    }
                }
                //7
                d = new X(-f.Fdx1(x) + Betta * d.X1, -f.Fdx2(x) + Betta * d.X2);
                //8
                Lambda = Dichotomy.GetMin((lambda) => f.F(new X(x.X1 + lambda * d.X1, x.X2 + lambda * d.X2)), -100, 100, 0.1);
                //9
                x_prev = x;
                x      = new X(x.X1 + Lambda * d.X1, x.X2 + Lambda * d.X2);
                //10
                k++;
            }
            Console.WriteLine(new String('-', 84));
            return(x);
        }