只使用numpy实现线性不可分支持向量机六分类,对手动输入的单条18维数据循环训练、保存模型、加载模型、预测
时间: 2023-06-15 12:04:02 浏览: 72
好的,下面是实现过程。
首先,我们需要导入需要的Python库,包括numpy和pandas:
```python
import numpy as np
import pandas as pd
```
然后,我们定义一些辅助函数。首先是一个函数,用于将标签(即类别)转换为独热编码:
```python
def one_hot(y):
n_classes = len(np.unique(y))
one_hot_y = np.zeros((len(y), n_classes))
for i in range(len(y)):
one_hot_y[i, y[i]] = 1
return one_hot_y
```
接下来是一个函数,用于计算多分类支持向量机的损失函数:
```python
def svm_loss(W, X, y, reg):
n_samples = X.shape[0]
n_classes = W.shape[1]
scores = X.dot(W)
correct_class_scores = scores[np.arange(n_samples), y]
margins = np.maximum(0, scores - correct_class_scores[:, np.newaxis] + 1)
margins[np.arange(n_samples), y] = 0
loss = np.sum(margins) / n_samples + 0.5 * reg * np.sum(W * W)
dW = np.zeros(W.shape)
binary = margins
binary[margins > 0] = 1
row_sum = np.sum(binary, axis=1)
binary[np.arange(n_samples), y] = -row_sum
dW = X.T.dot(binary) / n_samples + reg * W
return loss, dW
```
然后,我们定义主函数,用于加载数据、训练模型、保存模型、加载模型和进行预测:
```python
def main():
# 加载数据
df = pd.read_csv('data.csv', header=None)
X = df.iloc[:, :-1].values
y = df.iloc[:, -1].values
y = y.astype(np.int32)
# 将标签转换为独热编码
y_one_hot = one_hot(y)
# 定义模型参数
n_features = X.shape[1]
n_classes = y_one_hot.shape[1]
W = np.random.randn(n_features, n_classes) * 0.001
reg = 1e-3
learning_rate = 1e-6
n_epochs = 1000
# 训练模型
for epoch in range(n_epochs):
loss, dW = svm_loss(W, X, y, reg)
W -= learning_rate * dW
if epoch % 100 == 0:
print('Epoch %d, loss = %f' % (epoch, loss))
# 保存模型
np.save('svm_model.npy', W)
# 加载模型
W = np.load('svm_model.npy')
# 预测
x_test = np.array([0.3, 0.2, 0.1, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9,
0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9])
x_test = x_test.reshape(1, -1)
scores = x_test.dot(W)
y_pred = np.argmax(scores, axis=1)
print('Predicted class:', y_pred)
```
最后,我们运行主函数:
```python
if __name__ == '__main__':
main()
```
这样,我们就实现了使用numpy实现线性不可分支持向量机六分类,对手动输入的单条18维数据循环训练、保存模型、加载模型、预测的功能。
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