径向基函数神经网络的中心和核宽由FCM计算,径向基函数神经网络的权重设置为线性函数 ,该径向基函数神经网络的Python代码
时间: 2023-08-31 17:00:15 浏览: 65
RBF径向基神经网络Python代码文件
抱歉,上面的代码示例中没有包含模糊C均值(FCM)算法的实现。以下是一个完整的径向基函数神经网络的 Python 代码示例,包括了模糊C均值算法的实现:
```python
import numpy as np
def fuzzy_c_means(data, num_centers, max_iter=100, epsilon=1e-6):
num_samples, num_features = data.shape
centers = np.random.rand(num_centers, num_features)
membership = np.random.rand(num_samples, num_centers)
membership /= np.sum(membership, axis=1)[:, np.newaxis]
for _ in range(max_iter):
prev_centers = centers.copy()
# 更新聚类中心
for i in range(num_centers):
centers[i] = np.sum(data * (membership[:, i]**2)[:, np.newaxis], axis=0) / np.sum(membership[:, i]**2)
# 更新隶属度
distances = np.zeros((num_samples, num_centers))
for i in range(num_centers):
diff = data - centers[i]
distances[:, i] = np.sum(diff**2, axis=1)
membership = 1.0 / (distances + epsilon)
membership /= np.sum(membership, axis=1)[:, np.newaxis]
# 判断收敛条件
if np.sum(np.abs(centers - prev_centers)) < epsilon:
break
widths = np.zeros(num_centers)
for i in range(num_centers):
diff = data - centers[i]
widths[i] = np.max(np.sqrt(np.sum(diff**2, axis=1)))
return centers, widths
class RBFN:
def __init__(self, num_centers, num_features):
self.num_centers = num_centers
self.num_features = num_features
self.centers = None
self.widths = None
self.weights = None
def train(self, data, targets):
self.centers, self.widths = fuzzy_c_means(data, self.num_centers)
activation = self._calculate_activation(data)
# 使用线性回归训练权重
self.weights = np.linalg.lstsq(activation, targets, rcond=None)[0]
def _calculate_activation(self, data):
num_samples = data.shape[0]
activation = np.zeros((num_samples, self.num_centers))
for i in range(self.num_centers):
diff = data - self.centers[i]
activation[:, i] = np.exp(-0.5 * np.sum(diff**2 / self.widths[i]**2, axis=1))
return activation
def predict(self, data):
activation = self._calculate_activation(data)
predictions = np.dot(activation, self.weights)
return predictions
```
在这个代码中,我们添加了名为 `fuzzy_c_means` 的函数来实现模糊C均值(FCM)算法。这个函数用于计算聚类中心和核宽。其余部分的代码与之前的示例相同。注意,在 `RBFN` 类的构造函数中,我们将聚类中心、核宽和权重初始化为 `None`。这是因为我们需要在训练过程中通过调用 `train` 方法来计算这些值。
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