name 'plotdata' is not defined

I'm sorry, but I'm not sure what you're asking. It seems like you're telling me about an error message related to a variable or function called "plotdata". Can you please provide more context or information about what you're trying to do and where you're encountering this error? That way, I can better understand and assist you.

相关问题

qqnorm(plotdata$CWRES) qqline(plotdata$CWRES) 坐标轴标签设置

# 设置x轴标签
xlabel <- expression(paste("Theoretical quantiles of ", epsilon[i]))
# 设置y轴标签
ylabel <- expression(paste("CWRES of ", epsilon[i]))
# 绘制Q-Q图并添加坐标轴标签
qqnorm(plotdata$CWRES, xlab = xlabel, ylab = ylabel)
qqline(plotdata$CWRES)

机器学习 逻辑回归函数plotData部分核心matlab代码

在Matlab中，逻辑回归函数`plotData`的核心部分通常是用于可视化输入数据和预测结果的。假设我们已经有了特征变量`X`和对应的标签变量`y`，以及训练得到的逻辑回归系数`theta`，这里是一个简单的代码示例：

% 定义数据范围
x_min = min(X(:,1)); x_max = max(X(:,1));
y_min = min(y); y_max = max(y);

% 创建网格用于绘图
xx = linspace(x_min, x_max, 100);
yy = linspace(y_min, y_max, 100);
[X,Y] = meshgrid(xx, yy);
Z = sigmoid(dot([XX(:), ones(size(XX,1),1)], theta));

% 网格数据转置，方便绘制
Z = reshape(Z, size(X));

% 绘制数据点和预测边界
figure;
surf(X, Y, Z)
hold on
scatter3(X(:,1), X(:,2), y, 'filled')
xlabel('Feature 1');
ylabel('Feature 2');
zlabel('Probability');
title('Logistic Regression Decision Boundary');
hold off

在这个例子中，`sigmoid`函数用于计算逻辑回归的预测概率，`dot`函数用于向量乘法。`meshgrid`生成二维网格，`reshape`将概率数组转化为表面图的格式。最后，数据点和预测边界的图形都被添加到了同一个图表上。