多分类matlab实例
时间: 2023-05-25 20:05:04 浏览: 159
以下是一个简单的多分类 Matlab 实例,使用KNN算法来分类鸢尾花数据集:
1. 加载数据集:
```matlab
load fisheriris.mat;
X = meas(:, 1:2);
Y = species;
```
2. 将数据集分为训练集和测试集:
```matlab
[trainInd,valInd,testInd] = dividerand(size(X,1),0.6,0,0.4);
Xtrain = X(trainInd,:);
Ytrain = Y(trainInd,:);
Xtest = X(testInd,:);
Ytest = Y(testInd,:);
```
3. 定义模型和训练模型:
```matlab
mdl = fitcknn(Xtrain, Ytrain, 'NumNeighbors', 5);
```
4. 预测测试集:
```matlab
Ypred = predict(mdl, Xtest);
```
5. 计算分类准确率:
```matlab
accuracy = sum(Ypred == Ytest)/length(Ytest)
```
完整代码:
```matlab
load fisheriris.mat;
X = meas(:, 1:2);
Y = species;
[trainInd,valInd,testInd] = dividerand(size(X,1),0.6,0,0.4);
Xtrain = X(trainInd,:);
Ytrain = Y(trainInd,:);
Xtest = X(testInd,:);
Ytest = Y(testInd,:);
mdl = fitcknn(Xtrain, Ytrain, 'NumNeighbors', 5);
Ypred = predict(mdl, Xtest);
accuracy = sum(Ypred == Ytest)/length(Ytest)
```
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