# using MathNet Numerics LinearAlgebra Double using System using System

 ``` 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``` ```using MathNet.Numerics.LinearAlgebra.Double; using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Diagnostics; using System.Drawing; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Windows.Forms; namespace Exam3 { public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void Form1_Load(object sender, EventArgs e) { } private void Form1_Paint(object sender, PaintEventArgs e) { var g = e.Graphics; var D = new double[,]{{50,100},{100,200},{150,200},{200,100},}; int k = 3; var X = new int[] { 0, 0, 0, 1, 2, 2, 2 }; var N = new double[D.GetLength(0), 4]; var T = new double[] { 0, 0.817256, 1.182744, 2 }; for (var i = 0; i < D.GetLength(0); i++) { for (var j = 0; j < 4; j++) { N[i, j] = GetBasisFunc(j + 1, k, T[i], X); } } var Dmatrix = DenseMatrix.OfArray(D); var Nmatrix = DenseMatrix.OfArray(N); var NInverse = Nmatrix.Inverse(); var Bmatrix = NInverse * Dmatrix; var B = Bmatrix.ToArray(); for (var i = 0; i < B.GetLength(0); i++) { g.DrawEllipse(new Pen(Color.Blue), (float)B[i, 0], (float)B[i, 1], 4f, 4f); } for (double t = 0; t <= 2; t += 0.001) { double x = B[0, 0] * GetBasisFunc(1, k, t, X) + B[1, 0] * GetBasisFunc(2, k, t, X) + B[2, 0] * GetBasisFunc(3, k, t, X) + B[3, 0] * GetBasisFunc(4, k, t, X); double y = B[0, 1] * GetBasisFunc(1, k, t, X) + B[1, 1] * GetBasisFunc(2, k, t, X) + B[2, 1] * GetBasisFunc(3, k, t, X) + B[3, 1] * GetBasisFunc(4, k, t, X); g.DrawEllipse(new Pen(Color.Red), (float)x, (float)y, 2f, 2f); } } private double GetBasisFunc(int i, int k, double t, int[] X) { double result = 0; if (k == 1) { if ((t >= X[(i) - 1]) && (t <= X[(i + 1) - 1])) result = 1; else result = 0; } else { if (X[(i + k - 1) - 1] - X[(i) - 1] != 0) result = (t - X[(i) - 1]) * GetBasisFunc(i, k - 1, t, X) / (X[(i + k - 1) - 1] - X[(i) - 1]); if (X[(i + k) - 1] - X[(i + 1) - 1] != 0) result += (X[(i + k) - 1] - t) * GetBasisFunc(i + 1, k - 1, t, X) / (X[(i + k) - 1] - X[(i + 1) - 1]); } return result; } private void Form1_Paint_1(object sender, PaintEventArgs e) { var g = e.Graphics; var D = new double[,] { { 50, 100 }, { 100, 200 }, { 150, 200 }, { 200, 100 }, }; int k = 3; var X = new int[] { 0, 0, 0, 1, 2, 2, 2 }; var N = new double[D.GetLength(0), 4]; var T = new double[] { 0, 0.817256, 1.182744, 2 }; for (var i = 0; i < D.GetLength(0); i++) { for (var j = 0; j < 4; j++) { N[i, j] = GetBasisFunc(j + 1, k, T[i], X); } } var Dmatrix = DenseMatrix.OfArray(D); var Nmatrix = DenseMatrix.OfArray(N); var NInverse = Nmatrix.Inverse(); var Bmatrix = NInverse * Dmatrix; var B = Bmatrix.ToArray(); for (var i = 0; i < B.GetLength(0); i++) { g.DrawEllipse(new Pen(Color.Blue), (float)B[i, 0], (float)B[i, 1], 4f, 4f); } for (double t = 0; t <= 2; t += 0.001) { double x = B[0, 0] * GetBasisFunc(1, k, t, X) + B[1, 0] * GetBasisFunc(2, k, t, X) + B[2, 0] * GetBasisFunc(3, k, t, X) + B[3, 0] * GetBasisFunc(4, k, t, X); double y = B[0, 1] * GetBasisFunc(1, k, t, X) + B[1, 1] * GetBasisFunc(2, k, t, X) + B[2, 1] * GetBasisFunc(3, k, t, X) + B[3, 1] * GetBasisFunc(4, k, t, X); g.DrawEllipse(new Pen(Color.Red), (float)x, (float)y, 2f, 2f); } } } } ```