C#基于ScottPlot實(shí)現(xiàn)可視化的示例代碼
前言
上一篇文章跟大家分享了用NumSharp實(shí)現(xiàn)簡單的線性回歸,但是沒有進(jìn)行可視化,可能對擬合的過程沒有直觀的感受,因此今天跟大家介紹一下使用C#基于Scottplot進(jìn)行可視化,當(dāng)然Python的代碼,我也會同步進(jìn)行可視化。
Python代碼進(jìn)行可視化
Python代碼用matplotlib做了可視化,我就不具體介紹了。
修改之后的python代碼如下:
#The optimal values of m and b can be actually calculated with way less effort than doing a linear regression. #this is just to demonstrate gradient descent import numpy as np import matplotlib.pyplot as plt from matplotlib.animation import FuncAnimation # y = mx + b # m is slope, b is y-intercept def compute_error_for_line_given_points(b, m, points): totalError = 0 for i in range(0, len(points)): x = points[i, 0] y = points[i, 1] totalError += (y - (m * x + b)) ** 2 return totalError / float(len(points)) def step_gradient(b_current, m_current, points, learningRate): b_gradient = 0 m_gradient = 0 N = float(len(points)) for i in range(0, len(points)): x = points[i, 0] y = points[i, 1] b_gradient += -(2/N) * (y - ((m_current * x) + b_current)) m_gradient += -(2/N) * x * (y - ((m_current * x) + b_current)) new_b = b_current - (learningRate * b_gradient) new_m = m_current - (learningRate * m_gradient) return [new_b, new_m] def gradient_descent_runner(points, starting_b, starting_m, learning_rate, num_iterations): b = starting_b m = starting_m args_data = [] for i in range(num_iterations): b, m = step_gradient(b, m, np.array(points), learning_rate) args_data.append((b,m)) return args_data if __name__ == '__main__': points = np.genfromtxt("data.csv", delimiter=",") learning_rate = 0.0001 initial_b = 0 # initial y-intercept guess initial_m = 0 # initial slope guess num_iterations = 10 print ("Starting gradient descent at b = {0}, m = {1}, error = {2}".format(initial_b, initial_m, compute_error_for_line_given_points(initial_b, initial_m, points))) print ("Running...") args_data = gradient_descent_runner(points, initial_b, initial_m, learning_rate, num_iterations) b = args_data[-1][0] m = args_data[-1][1] print ("After {0} iterations b = {1}, m = {2}, error = {3}".format(num_iterations, b, m, compute_error_for_line_given_points(b, m, points))) data = np.array(points).reshape(100,2) x1 = data[:,0] y1 = data[:,1] x2 = np.linspace(20, 80, 100) y2 = initial_m * x2 + initial_b data2 = np.array(args_data) b_every = data2[:,0] m_every = data2[:,1] # 創(chuàng)建圖形和軸 fig, ax = plt.subplots() line1, = ax.plot(x1, y1, 'ro') line2, = ax.plot(x2,y2) # 添加標(biāo)簽和標(biāo)題 plt.xlabel('x') plt.ylabel('y') plt.title('Graph of y = mx + b') # 添加網(wǎng)格 plt.grid(True) # 定義更新函數(shù) def update(frame): line2.set_ydata(m_every[frame] * x2 + b_every[frame]) ax.set_title(f'{frame} Graph of y = {m_every[frame]:.2f}x + {b_every[frame]:.2f}') # 創(chuàng)建動畫 animation = FuncAnimation(fig, update, frames=len(data2), interval=500) # 顯示動畫 plt.show()
實(shí)現(xiàn)的效果如下所示:
C#代碼進(jìn)行可視化
這是本文重點(diǎn)介紹的內(nèi)容,本文的C#代碼通過Scottplot進(jìn)行可視化。
Scottplot簡介
ScottPlot 是一個免費(fèi)的開源繪圖庫,用于 .NET,可以輕松以交互方式顯示大型數(shù)據(jù)集。
控制臺程序可視化
首先我先介紹一下在控制臺程序中進(jìn)行可視化。
首先添加Scottplot包:
將上篇文章中的C#代碼修改如下:
using NumSharp; namespace LinearRegressionDemo { internal class Program { static void Main(string[] args) { //創(chuàng)建double類型的列表 List<double> Array = new List<double>(); List<double> ArgsList = new List<double>(); // 指定CSV文件的路徑 string filePath = "你的data.csv路徑"; // 調(diào)用ReadCsv方法讀取CSV文件數(shù)據(jù) Array = ReadCsv(filePath); var array = np.array(Array).reshape(100,2); double learning_rate = 0.0001; double initial_b = 0; double initial_m = 0; double num_iterations = 10; Console.WriteLine($"Starting gradient descent at b = {initial_b}, m = {initial_m}, error = {compute_error_for_line_given_points(initial_b, initial_m, array)}"); Console.WriteLine("Running..."); ArgsList = gradient_descent_runner(array, initial_b, initial_m, learning_rate, num_iterations); double b = ArgsList[ArgsList.Count - 2]; double m = ArgsList[ArgsList.Count - 1]; Console.WriteLine($"After {num_iterations} iterations b = , m = {m}, error = {compute_error_for_line_given_points(b, m, array)}"); Console.ReadLine(); var x1 = array[$":", 0]; var y1 = array[$":", 1]; var y2 = m * x1 + b; ScottPlot.Plot myPlot = new(400, 300); myPlot.AddScatterPoints(x1.ToArray<double>(), y1.ToArray<double>(), markerSize: 5); myPlot.AddScatter(x1.ToArray<double>(), y2.ToArray<double>(), markerSize: 0); myPlot.Title($"y = {m:0.00}x + {b:0.00}"); myPlot.SaveFig("圖片.png"); } static List<double> ReadCsv(string filePath) { List<double> array = new List<double>(); try { // 使用File.ReadAllLines讀取CSV文件的所有行 string[] lines = File.ReadAllLines(filePath); // 遍歷每一行數(shù)據(jù) foreach (string line in lines) { // 使用逗號分隔符拆分每一行的數(shù)據(jù) string[] values = line.Split(','); // 打印每一行的數(shù)據(jù) foreach (string value in values) { array.Add(Convert.ToDouble(value)); } } } catch (Exception ex) { Console.WriteLine("發(fā)生錯誤: " + ex.Message); } return array; } public static double compute_error_for_line_given_points(double b,double m,NDArray array) { double totalError = 0; for(int i = 0;i < array.shape[0];i++) { double x = array[i, 0]; double y = array[i, 1]; totalError += Math.Pow((y - (m*x+b)),2); } return totalError / array.shape[0]; } public static double[] step_gradient(double b_current,double m_current,NDArray array,double learningRate) { double[] args = new double[2]; double b_gradient = 0; double m_gradient = 0; double N = array.shape[0]; for (int i = 0; i < array.shape[0]; i++) { double x = array[i, 0]; double y = array[i, 1]; b_gradient += -(2 / N) * (y - ((m_current * x) + b_current)); m_gradient += -(2 / N) * x * (y - ((m_current * x) + b_current)); } double new_b = b_current - (learningRate * b_gradient); double new_m = m_current - (learningRate * m_gradient); args[0] = new_b; args[1] = new_m; return args; } public static List<double> gradient_descent_runner(NDArray array, double starting_b, double starting_m, double learningRate,double num_iterations) { double[] args = new double[2]; List<double> argsList = new List<double>(); args[0] = starting_b; args[1] = starting_m; for(int i = 0 ; i < num_iterations; i++) { args = step_gradient(args[0], args[1], array, learningRate); argsList.AddRange(args); } return argsList; } } }
然后得到的圖片如下所示:
在以上代碼中需要注意的地方:
var x1 = array[$":", 0]; var y1 = array[$":", 1];
是在使用NumSharp中的切片,x1表示所有行的第一列,y1表示所有行的第二列。
當(dāng)然我們不滿足于只是保存圖片,在控制臺應(yīng)用程序中,再添加一個 ScottPlot.WinForms包:
右鍵控制臺項目選擇屬性,將目標(biāo)OS改為Windows:
將上述代碼中的
myPlot.SaveFig("圖片.png");
修改為:
var viewer = new ScottPlot.FormsPlotViewer(myPlot); viewer.ShowDialog();
再次運(yùn)行結(jié)果如下:
winform進(jìn)行可視化
我也想像Python代碼中那樣畫動圖,因此做了個winform程序進(jìn)行演示。
首先創(chuàng)建一個winform,添加ScottPlot.WinForms包,然后從工具箱中添加FormsPlot這個控件:
有兩種方法實(shí)現(xiàn),第一種方法用了定時器:
using NumSharp; namespace WinFormDemo { public partial class Form1 : Form { System.Windows.Forms.Timer updateTimer = new System.Windows.Forms.Timer(); int num_iterations; int count = 0; NDArray? x1, y1, b_each, m_each; public Form1() { InitializeComponent(); } private void button1_Click(object sender, EventArgs e) { StartLinearRegression(); } public void StartLinearRegression() { //創(chuàng)建double類型的列表 List<double> Array = new List<double>(); List<double> ArgsList = new List<double>(); // 指定CSV文件的路徑 string filePath = "你的data.csv路徑"; // 調(diào)用ReadCsv方法讀取CSV文件數(shù)據(jù) Array = ReadCsv(filePath); var array = np.array(Array).reshape(100, 2); double learning_rate = 0.0001; double initial_b = 0; double initial_m = 0; num_iterations = 10; ArgsList = gradient_descent_runner(array, initial_b, initial_m, learning_rate, num_iterations); x1 = array[$":", 0]; y1 = array[$":", 1]; var argsArr = np.array(ArgsList).reshape(num_iterations, 2); b_each = argsArr[$":", 0]; m_each = argsArr[$":", 1]; double b = b_each[-1]; double m = m_each[-1]; var y2 = m * x1 + b; formsPlot1.Plot.AddScatterPoints(x1.ToArray<double>(), y1.ToArray<double>(), markerSize: 5); //formsPlot1.Plot.AddScatter(x1.ToArray<double>(), y2.ToArray<double>(), markerSize: 0); formsPlot1.Render(); } static List<double> ReadCsv(string filePath) { List<double> array = new List<double>(); try { // 使用File.ReadAllLines讀取CSV文件的所有行 string[] lines = File.ReadAllLines(filePath); // 遍歷每一行數(shù)據(jù) foreach (string line in lines) { // 使用逗號分隔符拆分每一行的數(shù)據(jù) string[] values = line.Split(','); // 打印每一行的數(shù)據(jù) foreach (string value in values) { array.Add(Convert.ToDouble(value)); } } } catch (Exception ex) { Console.WriteLine("發(fā)生錯誤: " + ex.Message); } return array; } public static double compute_error_for_line_given_points(double b, double m, NDArray array) { double totalError = 0; for (int i = 0; i < array.shape[0]; i++) { double x = array[i, 0]; double y = array[i, 1]; totalError += Math.Pow((y - (m * x + b)), 2); } return totalError / array.shape[0]; } public static double[] step_gradient(double b_current, double m_current, NDArray array, double learningRate) { double[] args = new double[2]; double b_gradient = 0; double m_gradient = 0; double N = array.shape[0]; for (int i = 0; i < array.shape[0]; i++) { double x = array[i, 0]; double y = array[i, 1]; b_gradient += -(2 / N) * (y - ((m_current * x) + b_current)); m_gradient += -(2 / N) * x * (y - ((m_current * x) + b_current)); } double new_b = b_current - (learningRate * b_gradient); double new_m = m_current - (learningRate * m_gradient); args[0] = new_b; args[1] = new_m; return args; } public static List<double> gradient_descent_runner(NDArray array, double starting_b, double starting_m, double learningRate, double num_iterations) { double[] args = new double[2]; List<double> argsList = new List<double>(); args[0] = starting_b; args[1] = starting_m; for (int i = 0; i < num_iterations; i++) { args = step_gradient(args[0], args[1], array, learningRate); argsList.AddRange(args); } return argsList; } private void button2_Click(object sender, EventArgs e) { // 初始化定時器 updateTimer.Interval = 1000; // 設(shè)置定時器觸發(fā)間隔(毫秒) updateTimer.Tick += UpdateTimer_Tick; updateTimer.Start(); } private void UpdateTimer_Tick(object? sender, EventArgs e) { if (count >= num_iterations) { updateTimer.Stop(); } else { UpdatePlot(count); } count++; } public void UpdatePlot(int count) { double b = b_each?[count]; double m = m_each?[count]; var y2 = m * x1 + b; formsPlot1.Plot.Clear(); formsPlot1.Plot.AddScatterPoints(x1?.ToArray<double>(), y1?.ToArray<double>(), markerSize: 5); formsPlot1.Plot.AddScatter(x1?.ToArray<double>(), y2.ToArray<double>(), markerSize: 0); formsPlot1.Plot.Title($"第{count + 1}次迭代:y = {m:0.00}x + {b:0.00}"); formsPlot1.Render(); } private void button3_Click(object sender, EventArgs e) { updateTimer.Stop(); } private void Form1_Load(object sender, EventArgs e) { } } }
簡單介紹一下思路,首先創(chuàng)建List<double> argsList
用來保存每次迭代生成的參數(shù)b、m,然后用
var argsArr = np.array(ArgsList).reshape(num_iterations, 2);
將argsList
通過np.array()方法轉(zhuǎn)化為NDArray,然后再調(diào)用reshape方法,轉(zhuǎn)化成行數(shù)等于迭代次數(shù),列數(shù)為2,即每一行對應(yīng)一組參數(shù)值b、m。
b_each = argsArr[$":", 0]; m_each = argsArr[$":", 1];
argsArr[$":", 0]
表示每一行中第一列的值,也就是每一個b,argsArr[$":", 1]
表示每一行中第二列的值。
double b = b_each[-1]; double m = m_each[-1];
b_each[-1]
用了NumSharp的功能表示b_each
最后一個元素。
實(shí)現(xiàn)效果如下所示:
另一種方法可以通過異步實(shí)現(xiàn):
using NumSharp; namespace WinFormDemo { public partial class Form2 : Form { int num_iterations; NDArray? x1, y1, b_each, m_each; public Form2() { InitializeComponent(); } private void button1_Click(object sender, EventArgs e) { StartLinearRegression(); } public void StartLinearRegression() { //創(chuàng)建double類型的列表 List<double> Array = new List<double>(); List<double> ArgsList = new List<double>(); // 指定CSV文件的路徑 string filePath = "你的data.csv路徑"; // 調(diào)用ReadCsv方法讀取CSV文件數(shù)據(jù) Array = ReadCsv(filePath); var array = np.array(Array).reshape(100, 2); double learning_rate = 0.0001; double initial_b = 0; double initial_m = 0; num_iterations = 10; ArgsList = gradient_descent_runner(array, initial_b, initial_m, learning_rate, num_iterations); x1 = array[$":", 0]; y1 = array[$":", 1]; var argsArr = np.array(ArgsList).reshape(num_iterations, 2); b_each = argsArr[$":", 0]; m_each = argsArr[$":", 1]; double b = b_each[-1]; double m = m_each[-1]; var y2 = m * x1 + b; formsPlot1.Plot.AddScatterPoints(x1.ToArray<double>(), y1.ToArray<double>(), markerSize: 5); formsPlot1.Render(); } static List<double> ReadCsv(string filePath) { List<double> array = new List<double>(); try { // 使用File.ReadAllLines讀取CSV文件的所有行 string[] lines = File.ReadAllLines(filePath); // 遍歷每一行數(shù)據(jù) foreach (string line in lines) { // 使用逗號分隔符拆分每一行的數(shù)據(jù) string[] values = line.Split(','); // 打印每一行的數(shù)據(jù) foreach (string value in values) { array.Add(Convert.ToDouble(value)); } } } catch (Exception ex) { Console.WriteLine("發(fā)生錯誤: " + ex.Message); } return array; } public static double compute_error_for_line_given_points(double b, double m, NDArray array) { double totalError = 0; for (int i = 0; i < array.shape[0]; i++) { double x = array[i, 0]; double y = array[i, 1]; totalError += Math.Pow((y - (m * x + b)), 2); } return totalError / array.shape[0]; } public static double[] step_gradient(double b_current, double m_current, NDArray array, double learningRate) { double[] args = new double[2]; double b_gradient = 0; double m_gradient = 0; double N = array.shape[0]; for (int i = 0; i < array.shape[0]; i++) { double x = array[i, 0]; double y = array[i, 1]; b_gradient += -(2 / N) * (y - ((m_current * x) + b_current)); m_gradient += -(2 / N) * x * (y - ((m_current * x) + b_current)); } double new_b = b_current - (learningRate * b_gradient); double new_m = m_current - (learningRate * m_gradient); args[0] = new_b; args[1] = new_m; return args; } public static List<double> gradient_descent_runner(NDArray array, double starting_b, double starting_m, double learningRate, double num_iterations) { double[] args = new double[2]; List<double> argsList = new List<double>(); args[0] = starting_b; args[1] = starting_m; for (int i = 0; i < num_iterations; i++) { args = step_gradient(args[0], args[1], array, learningRate); argsList.AddRange(args); } return argsList; } private void Form2_Load(object sender, EventArgs e) { } public async Task UpdateGraph() { for (int i = 0; i < num_iterations; i++) { double b = b_each?[i]; double m = m_each?[i]; var y2 = m * x1 + b; formsPlot1.Plot.Clear(); formsPlot1.Plot.AddScatterPoints(x1?.ToArray<double>(), y1?.ToArray<double>(), markerSize: 5); formsPlot1.Plot.AddScatter(x1?.ToArray<double>(), y2.ToArray<double>(), markerSize: 0); formsPlot1.Plot.Title($"第{i + 1}次迭代:y = {m:0.00}x + {b:0.00}"); formsPlot1.Render(); await Task.Delay(1000); } } private async void button2_Click(object sender, EventArgs e) { await UpdateGraph(); } } }
點(diǎn)擊更新按鈕開始執(zhí)行異步任務(wù):
private async void button2_Click(object sender, EventArgs e) { await UpdateGraph(); }
public async Task UpdateGraph() { for (int i = 0; i < num_iterations; i++) { double b = b_each?[i]; double m = m_each?[i]; var y2 = m * x1 + b; formsPlot1.Plot.Clear(); formsPlot1.Plot.AddScatterPoints(x1?.ToArray<double>(), y1?.ToArray<double>(), markerSize: 5); formsPlot1.Plot.AddScatter(x1?.ToArray<double>(), y2.ToArray<double>(), markerSize: 0); formsPlot1.Plot.Title($"第{i + 1}次迭代:y = {m:0.00}x + {b:0.00}"); formsPlot1.Render(); await Task.Delay(1000); }
實(shí)現(xiàn)效果如下:
以上就是C#基于ScottPlot實(shí)現(xiàn)可視化的示例代碼的詳細(xì)內(nèi)容,更多關(guān)于C# ScottPlot可視化的資料請關(guān)注腳本之家其它相關(guān)文章!
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