使用latex绘制多层神经网络结构图

1，使用Tikz包；

2，参考官方例程单层神经网络结构，绘制了一个含有3隐藏层的BP神经网络节点图

代码如下：

 \documentclass{article}

 \usepackage{tikz}
 \begin{document}
 \pagestyle{empty}

 \def\layersep{2.5cm}

 \begin{tikzpicture}[shorten >=1pt,->,draw=black!50, node distance=\layersep]
     \tikzstyle{every pin edge}=[<-,shorten <=1pt]
     \tikzstyle{neuron}=[circle,fill=black!25,minimum size=17pt,inner sep=0pt]
     \tikzstyle{input neuron}=[neuron, fill=green!50];
     \tikzstyle{output neuron}=[neuron, fill=red!50];

     \tikzstyle{hidden neuron1}=[neuron, fill=blue!50];
     \tikzstyle{hidden neuron2}=[neuron, fill=blue!50];
     \tikzstyle{hidden neuron3}=[neuron, fill=blue!50];

     \tikzstyle{annot} = [text width=4em, text centered]

     % Draw the input layer nodes
     \foreach \name / \y in {1,...,4}
     % This is the same as writing \foreach \name / \y in {1/1,2/2,3/3,4/4}
         \node[input neuron, pin=left:Input \#\y] (I-\name) at (0,-\y) {};

     % Draw the hidden layer1 nodes
     \foreach \name / \y in {1,...,5}
         \path[yshift=0.5cm]
             node[hidden neuron1] (H1-\name) at (\layersep,-\y cm) {};
    %Draw the hidden layer2 nodes
     \foreach \name / \y in {1,...,5}
         \path[yshift=0.5cm]
             node[hidden neuron2,right of=H1] (H2-\name) at (\layersep,-\y cm){};
     %Draw the hidden layer3 nodes
     \foreach \name / \y in {1,...,5}
         \path[yshift=0.5cm]
             node[hidden neuron3,right of=H2] (H3-\name) at (2*\layersep,-\y cm){};

     % Draw the output layer node
     \node[output neuron,pin={[pin edge={->}]right:Output}, right of=H3-3] (O) {};

     % Connect every node in the input layer with every node in the
     % hidden layer.
     \foreach \source in {1,...,4}
         \foreach \dest in {1,...,5}
             \path (I-\source) edge (H1-\dest);
     %
     \foreach \source in {1,...,5}
         \foreach \dest in {1,...,5}
             \path (H1-\source) edge (H2-\dest);
     %
     \foreach \source in {1,...,5}
         \foreach \dest in {1,...,5}
             \path (H2-\source) edge (H3-\dest);
     % Connect every node in the hidden layer with the output layer
     \foreach \source in {1,...,5}
         \path (H3-\source) edge (O);

     % Annotate the layers
     \node[annot,above of=H1-1, node distance=1cm] (hl) {Hidden layer1};
     \node[annot,left of=hl] {Input layer};
     \node[annot,right of=hl] (h2){Hidden layer2};
     \node[annot,right of=h2] (h3){Hidden layer3};
     \node[annot,right of=h3] {Output layer};
 \end{tikzpicture}
 % End of code
 \end{document}

效果如图：