基于图坍缩的图多分类代码实现,要求使用自己随机生成的数据集进行训练和预测
时间: 2024-02-03 20:13:58 浏览: 82
以下是基于图坍缩的图多分类代码实现,使用Python编写,使用scikit-learn库进行建模和训练:
```
import numpy as np
from sklearn.datasets import make_classification
from sklearn.model_selection import train_test_split
from sklearn.pipeline import Pipeline
from sklearn.preprocessing import StandardScaler
from sklearn.svm import SVC
from sklearn.metrics import accuracy_score
from sklearn.base import BaseEstimator, TransformerMixin
class GraphTransformer(BaseEstimator, TransformerMixin):
"""
图坍缩转换器
"""
def __init__(self, threshold=0.5):
self.threshold = threshold
def fit(self, X, y=None):
return self
def transform(self, X):
# 计算相似度矩阵
N = X.shape[0]
similarity = np.zeros((N, N))
for i in range(N):
for j in range(i+1, N):
similarity[i,j] = similarity[j,i] = np.exp(-np.sum(np.square(X[i]-X[j])))
# 计算权重矩阵
weights = np.zeros((N, N))
for i in range(N):
for j in range(i+1, N):
if similarity[i,j] >= self.threshold:
weights[i,j] = weights[j,i] = 1
# 构建连通图
graph = {}
for i in range(N):
graph[i] = set([j for j in range(N) if weights[i,j]==1])
# 图坍缩
labels = [i for i in range(N)]
while len(graph) > 1:
u, v = min([(u, v) for u in graph for v in graph[u] if u != v], key=lambda x: weights[x])
graph[u].update(graph[v])
del graph[v]
labels[v] = u
return np.array([labels]).T
# 随机生成数据集
X, y = make_classification(n_samples=100, n_features=10, n_classes=5, random_state=42)
# 划分训练集和测试集
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2, random_state=42)
# 构建Pipeline并进行训练和预测
pipe = Pipeline([
('scaler', StandardScaler()),
('graph', GraphTransformer(threshold=0.5)),
('svm', SVC(kernel='rbf', C=1, gamma='scale', random_state=42))
])
pipe.fit(X_train, y_train)
y_pred = pipe.predict(X_test)
# 计算准确率
acc = accuracy_score(y_test, y_pred)
print('Accuracy:', acc)
```
说明:
1. 代码中使用scikit-learn库中的`make_classification`函数随机生成一个包含100个样本、10个特征、5个类别的数据集。
2. `GraphTransformer`是一个自定义的转换器类,用于将原始数据集转换为连通图上的标签。其中`fit`方法不需要做任何事情,`transform`方法根据相似度矩阵和阈值计算权重矩阵,构建连通图,并进行图坍缩。
3. Pipeline中包含了三个步骤:数据标准化、图坍缩转换和SVM分类器。其中SVM分类器使用径向基函数(RBF)作为核函数。
4. 计算准确率并输出。
使用自己随机生成的数据集进行训练和预测,只需要将代码中的数据集替换为自己的数据即可。
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