using System;

public class Program

{

    public static void Main()

     {

            double error_cuadrado_total, error_cuadrado_total_viejo,

                variable_criterio = 0.0001;

            double pivote, factor;

            double[] r = new double[18];

            double[,] jacobiana = new double[18, 4];

            double[,] matriz = { { 0, 0, 0, 0, 0 },

                               { 0, 0, 0, 0, 0 },

                               { 0, 0, 0, 0, 0 },

                               { 0, 0, 0, 0, 0 } };

​

            //Temperaturas de cada mes

            double[] temp = {65, 69, 76, 82, 89, 94, 96, 96, 92, 85, 76, 67, 58, 60, 70, 80, 82, 893};

            double[] mes = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18 };

​

            //Valores iniciales

            double[] x = { 17, 0.5, 10.5, 77 };

​

            error_cuadrado_total_viejo = variable_criterio * 2;

            error_cuadrado_total = 0;

​

            while (Math.Abs(error_cuadrado_total - error_cuadrado_total_viejo)

                > variable_criterio)

            {

                error_cuadrado_total_viejo = error_cuadrado_total;

                error_cuadrado_total = 0;

​

                for (int i = 0; i < 18; i = i + 1)

                {

                    r[i] = x[0] * Math.Sin(x[1] * mes[i] + x[2]) + x[3] - temp[i];

                    error_cuadrado_total = error_cuadrado_total + r[i] * r[i];

​

                    jacobiana[i, 0] = Math.Sin(mes[i] * x[1] + x[2]);

                    jacobiana[i, 1] = mes[i] * x[0] * Math.Cos(mes[i] * x[1] + x[2]);

                    jacobiana[i, 2] = x[0] * Math.Cos(mes[i] * x[1] + x[2]);

                    jacobiana[i, 3] = 1;

                }

                //Multiplicación de matrices

                //------------------------------

                for (int i = 0; i < 4; i = i + 1)

                    for (int j = 0; j < 4; j = j + 1)

                        for (int k = 0; k < 18; k = k + 1)

                            matriz[i, j]

                                = matriz[i, j] + jacobiana[k, i] * jacobiana[k, j];

​

                for (int i = 0; i < 4; i = i + 1)

                    for (int j = 0; j < 1; j = j + 1)

                        for (int k = 0; k < 18; k = k + 1)

                            matriz[i, 4] = matriz[i, 4] - r[k] * jacobiana[k, i];

                //------------------------------

​

                //Eliminación Gaussiana

                //------------------------------

                for (int reng = 0; reng < 4; reng = reng + 1)

                {

                    pivote = matriz[reng, reng];

                    for (int colu = 0; colu < 5; colu = colu + 1)

                        matriz[reng, colu] = matriz[reng, colu] / pivote;

                    for (int reng_elimi = 0; reng_elimi < 4; reng_elimi = reng_elimi + 1)

                        if (reng_elimi != reng)

                        {

                            factor = matriz[reng_elimi, reng];

                            for (int colu_elimi = 0; colu_elimi < 5;

                                colu_elimi = colu_elimi + 1)

                                matriz[reng_elimi, colu_elimi]

                                    = matriz[reng_elimi, colu_elimi]

                                    - factor * matriz[reng, colu_elimi];

                        }

                }

                //------------------------------

​

                //Imprime los valores de las variables

                Console.WriteLine(x[0]+" "+x[1]+" "+x[2]+" "+x[3]

                    +" "+error_cuadrado_total);

            }

​

            Console.ReadLine();

}

}