keras可视化遇到pydot&graphviz无法导入问题

python使用pydot报错：OSError: `pydot` failed to call GraphViz.Please install GraphViz (https://www.graphviz.org/) and ensure that its executables are in the $PATH.

首先确保pip install pydot；pip install pydot-ng；pip install graphviz

如果还报错：原因其实不在于pydot，跟python包没有关系，而是因为graphviz需要安装二进制执行文件（跟imagick类似），所以还需要去官网下一个graphviz安装包安装：https://graphviz.gitlab.io/_pages/Download/Download_windows.html

下载gtapviz.zip解压后在系统变量中添加路径即可.

如果执行起来还有有报错的话，就用终极大法，在代码中添加其路径：

import os
os.environ["PATH"] += os.pathsep + 'G:/17/graphviz/bin/'

代码如下

1. import numpy as np
2. from keras.models import Sequential
3. from keras.layers.core import Dense, Activation
4. from keras.optimizers import SGD
5. from keras.utils import np_utils
6. from keras.utils import plot_model
7. import os
8. os.environ["PATH"] += os.pathsep + 'G:/17/graphviz/bin/'
9.  
10. def run():
11.     # 构建神经网络
12.     model = Sequential()
13.     model.add(Dense(4, input_dim=2, kernel_initializer='uniform'))
14.     model.add(Activation('relu'))
15.     model.add(Dense(2, kernel_initializer='uniform'))
16.     model.add(Activation('sigmoid'))
17.     sgd = SGD(lr=0.05, decay=1e-6, momentum=0.9, nesterov=True)
18.     model.compile(loss='binary_crossentropy', optimizer=sgd, metrics=['accuracy'])
19.  
20.     # 神经网络可视化
21.     plot_model(model, to_file='model.png')
22.  
23. if __name__ == '__main__':
24.     run()

结果如下：