%%%------------------------------------------------------------------------------------------------------------
\begin{tikzpicture}
\begin{scope}

\tikzstyle{neuronnode} = [minimum size=1.5em,circle,draw,ublue,very thick,fill=white,drop shadow={shadow xshift=0.1em,shadow yshift=-0.1em}]

\node [anchor=center,neuronnode] (neuron00) at (0,0) {};
\node [anchor=center,neuronnode] (neuron01) at ([yshift=-3em]neuron00) {};
\node [anchor=center,neuronnode] (neuron02) at ([yshift=-3em]neuron01) {};
\node [anchor=east] (x0) at ([xshift=-6em]neuron00.west) {$x_1$};
\node [anchor=east] (x1) at ([xshift=-6em]neuron01.west) {$x_2$};
\node [anchor=east] (x2) at ([xshift=-6em]neuron02.west) {$\mathbi{b}$};
\node [anchor=west] (y0) at ([xshift=4em]neuron00.east) {$y_1$};

\draw [->] (x0.east) -- (neuron00.180) node [pos=0.1,above] {\tiny{$w_{11}$}};
\draw [->] (x1.east) -- (neuron00.200) node [pos=0.1,above] {\tiny{$w_{21}$}};
\draw [->] (x2.east) -- (neuron00.220) node [pos=0.05,above,yshift=0.3em] {\tiny{$b_{1}$}};
\draw [->] (neuron00.east) -- (y0.west);

\node [anchor=west] (y1) at ([xshift=4em]neuron01.east) {$y_2$};
\draw [->] (x0.east) -- (neuron01.160) node [pos=0.4,above] {\tiny{$w_{12}$}};
\draw [->] (x1.east) -- (neuron01.180) node [pos=0.35,above,yshift=-0.2em] {\tiny{$w_{22}$}};
\draw [->] (x2.east) -- (neuron01.200) node [pos=0.3,below,yshift=0.2em] {\tiny{$b_{2}$}};
\draw [->] (neuron01.east) -- (y1.west);

\node [anchor=west] (y2) at ([xshift=4em]neuron02.east) {$y_3$};
\draw [->] (x0.east) -- (neuron02.140) node [pos=0.1,below,yshift=-0.2em] {\tiny{$w_{13}$}};
\draw [->] (x1.east) -- (neuron02.160) node [pos=0.1,below] {\tiny{$w_{23}$}};
\draw [->] (x2.east) -- (neuron02.180) node [pos=0.3,below] {\tiny{$b_{3}$}};
\draw [->] (neuron02.east) -- (y2.west);

\node [anchor=east,align=left] (inputlabel) at ([xshift=-0.1em]x1.west) {\scriptsize{输入向量}:\\\small{$\mathbi{x}=(x_1,x_2)$}};


\node [anchor=west,align=left] (outputlabel) at ([xshift=0.1em]y1.east) {\scriptsize{输出向量}:\\\small{$\mathbi{y}=(y_1,y_2,y_3)$}};


\begin{pgfonlayer}{background}

\node [rectangle,inner sep=0.4em,fill=red!20] [fit = (neuron00) (neuron01) (neuron02)] (layer) {};
\node [anchor=south] (layerlabel) at ([yshift=0.2em]layer.north) {\scriptsize{一层神经元}};



\node [rectangle,inner sep=0.1em,fill=ugreen!20] [fit = (x0) (x1)] (inputshadow) {};


\node [rectangle,inner sep=0.1em,fill=blue!20] [fit = (y0) (y1) (y2)] (outputshadow) {};

\end{pgfonlayer}



\end{scope}
\end{tikzpicture}
%%%------------------------------------------------------------------------------------------------------------

