# using System using System Collections Generic using System Linq using

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168``` ```using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace LU { class Method { public double[,] _Amatrix = new double[,] { { 1, 1, -3, 4 }, { 3, 5, 6, 9 }, { 1, 1, 2, 2 }, { 2, 3, -1, 2 } }; public double[] _Barray = new double[] { 1, 2, 3, 4 }; public double[] _Xarray; public double[] _Yarray; public double[,] _Lmatrix = new double[,] { { 1, 0, 0 , 0 }, { 1, 1, 0, 0 }, { 1, 1, 1, 0 }, { 1, 1, 1, 1 } }; public double[,] _Umatrix; public void LU() { _Umatrix = new double[_Amatrix.GetLength(0), _Amatrix.GetLength(1)]; _Umatrix = _Amatrix; int n = _Amatrix.GetLength(0); for (int i = 0; i < n; i++) { for (int j = i; j < n; j++) { _Lmatrix[j, i] = _Umatrix[j, i] / _Umatrix[i, i]; } } for (int k = 1; k < n; k++) { for (int i = k - 1; i < n; i++) { for (int j = i; j < n; j++) { _Lmatrix[j, i] = _Umatrix[j, i] / _Umatrix[i, i]; } } for (int i = k; i < n; i++) { for (int j = k - 1; j < n; j++) { _Umatrix[i, j] = _Umatrix[i, j] - _Lmatrix[i, k - 1] * _Umatrix[k - 1, j]; } } } } public void solution() { _Yarray = new double[_Barray.Length]; _Xarray = new double[_Barray.Length]; for (int i = 0; i < _Barray.Length; i++) { _Yarray[i] = 0; _Xarray[i] = 0; } for (int i = 0; i < _Lmatrix.GetLength(0); ++i) { double sum = 0; for (int k = 0; k < i; ++k) { sum += _Lmatrix[i, k] * _Yarray[k]; } _Yarray[i] = (_Barray[i] - sum) / _Lmatrix[i, i]; } for (int i = _Umatrix.GetLength(0) - 1; i >= 0; i--) { double sum = 0; for (int k = _Umatrix.GetLength(0) - 1; k >= i; k--) { sum += _Umatrix[i, k] * _Xarray[k]; } _Xarray[i] = (_Yarray[i] - sum) / _Umatrix[i, i]; } } } class Program { static void Main(string[] args) { Method method = new Method(); Console.WriteLine("Исходная марица:"); for (int i = 0; i < method._Amatrix.GetLength(0); i++) { for (int j = 0; j < method._Amatrix.GetLength(1); j++) { Console.Write("{0:f1} \t", method._Amatrix[i, j]); } Console.WriteLine(); } method.LU(); Console.WriteLine(); Console.WriteLine(); Console.WriteLine("L матрица:"); for (int i = 0; i < method._Amatrix.GetLength(0); i++) { for (int j = 0; j < method._Amatrix.GetLength(1); j++) { Console.Write("{0:f2} \t", method._Lmatrix[i, j]); } Console.WriteLine(); } Console.WriteLine(); Console.WriteLine(); Console.WriteLine("U матрица:"); for (int i = 0; i < method._Amatrix.GetLength(0); i++) { for (int j = 0; j < method._Amatrix.GetLength(1); j++) { Console.Write("{0:f2} \t", method._Umatrix[i, j]); } Console.WriteLine(); } Console.WriteLine(); Console.WriteLine(); method.solution(); Console.WriteLine("Корни:"); for (int i = 0; i < method._Barray.Length; i++) { Console.WriteLine("{0:f3}" , method._Xarray[i]); } Console.ReadKey(); } } } ```