写出代码利用函数读取abalone.txt数据,并训练LWLR模型,比较不同k值下,模型在训练样本上的误差值
时间: 2024-03-07 08:49:05 浏览: 131
好的,以下是代码实现:
```python
import numpy as np
# 读取数据
def load_data(filename):
data = np.loadtxt(filename, delimiter='\t')
x = data[:, :-1]
y = data[:, -1]
return x, y
# LWLR模型
def lwlr(test_point, x, y, k=1.0):
x_mat = np.mat(x)
y_mat = np.mat(y).reshape(-1, 1)
m = np.shape(x_mat)[0]
weights = np.mat(np.eye(m))
for j in range(m):
diff = test_point - x_mat[j, :]
weights[j, j] = np.exp(diff * diff.T / (-2.0 * k ** 2))
xTx = x_mat.T * (weights * x_mat)
if np.linalg.det(xTx) == 0.0:
print('This matrix is singular, cannot do inverse')
return
ws = xTx.I * (x_mat.T * (weights * y_mat))
return test_point * ws
# 计算误差
def error(x, y, k):
m = np.shape(x)[0]
error = 0.0
for i in range(m):
y_pred = lwlr(x[i], x, y, k)
error += (y_pred - y[i]) ** 2
return error
# 测试不同k值下的误差
if __name__ == '__main__':
x, y = load_data('abalone.txt')
k_list = [0.1, 1, 10]
for k in k_list:
print('k={}'.format(k))
print('train error: {:.2f}'.format(error(x, y, k)))
```
代码中使用`load_data`函数读取数据,使用`lwlr`函数训练LWLR模型,使用`error`函数计算模型在训练样本上的误差值。最后,测试不同的k值下,模型在训练样本上的误差值。
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