Github
- https://github.com/matplotlib/matplotlib
官网
- https://matplotlib.org/stable/
文档
- https://matplotlib.org/stable/api/index.html
简介
matplotlib 是 Python 中最常用的绘图库之一,用于创建各种类型的静态、动态和交互式可视化。
动态显示训练过程中的数据和模子的决策边界
安装
- pip install tensorflow==2.13.1
- pip install matplotlib==3.7.5
- pip install numpy==1.24.3
复制代码 源码
- import numpy as np
- import tensorflow as tf
- from tensorflow.keras.models import Sequential
- from tensorflow.keras.layers import Dense
- import matplotlib.pyplot as plt
- from matplotlib.colors import ListedColormap
- # 生成数据
- np.random.seed(0)
- num_samples_per_class = 500
- negative_samples = np.random.multivariate_normal(
- mean=[0, 3],
- cov=[[1, 0.5], [0.5, 1]],
- size=num_samples_per_class
- )
- positive_samples = np.random.multivariate_normal(
- mean=[3, 0],
- cov=[[1, 0.5], [0.5, 1]],
- size=num_samples_per_class
- )
- inputs = np.vstack((negative_samples, positive_samples)).astype(np.float32)
- targets = np.vstack((np.zeros((num_samples_per_class, 1)), np.ones((num_samples_per_class, 1)))).astype(np.float32)
- # 将数据分为训练集和测试集
- train_size = int(0.8 * len(inputs))
- X_train, X_test = inputs[:train_size], inputs[train_size:]
- y_train, y_test = targets[:train_size], targets[train_size:]
- # 构建二分类模型
- model = Sequential([
- # 输入层:输入形状为 (2,)
- # 第一个隐藏层:包含 4 个节点,激活函数使用 ReLU
- Dense(4, activation='relu', input_shape=(2,)),
-
- # 输出层:包含 1 个节点,激活函数使用 Sigmoid(因为是二分类问题)
- Dense(1, activation='sigmoid')
- ])
- # 编译模型
- # 指定优化器为 Adam,损失函数为二分类交叉熵,评估指标为准确率
- model.compile(optimizer='adam', loss='binary_crossentropy', metrics=['accuracy'])
- # 准备绘图
- fig, ax = plt.subplots()
- cmap_light = ListedColormap(['#FFAAAA', '#AAAAFF'])
- cmap_bold = ListedColormap(['#FF0000', '#0000FF'])
- # 动态绘制函数
- def plot_decision_boundary(epoch, logs):
- ax.clear()
- x_min, x_max = X_train[:, 0].min() - 1, X_train[:, 0].max() + 1
- y_min, y_max = X_train[:, 1].min() - 1, X_train[:, 1].max() + 1
- xx, yy = np.meshgrid(np.arange(x_min, x_max, 0.1),
- np.arange(y_min, y_max, 0.1))
- grid = np.c_[xx.ravel(), yy.ravel()]
- probs = model.predict(grid).reshape(xx.shape)
- ax.contourf(xx, yy, probs, alpha=0.8, cmap=cmap_light)
- ax.scatter(X_train[:, 0], X_train[:, 1], c=y_train[:, 0], edgecolor='k', cmap=cmap_bold)
- ax.set_title(f'Epoch {epoch+1}')
- plt.draw()
- plt.pause(0.01)
- # 自定义回调函数
- class PlotCallback(tf.keras.callbacks.Callback):
- def on_epoch_end(self, epoch, logs=None):
- plot_decision_boundary(epoch, logs)
- # 训练模型并动态显示
- plot_callback = PlotCallback()
- model.fit(X_train, y_train, epochs=50, batch_size=16, callbacks=[plot_callback])
- # 评估模型
- loss, accuracy = model.evaluate(X_test, y_test)
- print(f"Test Loss: {loss}")
- print(f"Test Accuracy: {accuracy}")
- plt.show()
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