%%%------------------------------------------------------------------------------------------------------------
\begin{tikzpicture}
%左
\node [anchor=west,draw=ublue,minimum width=1.5em,minimum height=1.5em] (part1-1) at (0,0) {\small{$x_1$}};
\node [anchor=north,draw=ublue,minimum width=1.5em,minimum height=1.5em] (part1-2) at ([yshift=-2.5em]part1-1.south) {\small {$x_2$}};
\node [anchor=north,draw=ublue,minimum width=1.5em,minimum height=1.5em] (part1-3) at ([yshift=-2.5em]part1-2.south) {\small {$x_3$}};
\node [anchor=north,minimum width=3.0em] (part1-4) at ([yshift=-1.0em]part1-3.south) {\small {输入层}};
\node[anchor=south,minimum height=13em,minimum width=4.0em,draw=ublue,dotted,thick] (part1out) at ([xshift=0.0em,yshift=-8.5em]part1-2.north) {};

%中
\node [circle,anchor=west,draw=ublue,minimum width=2.0em] (part2-1) at ([xshift=4.6em,yshift=2.0em]part1-2.east) {\small {$a_1$}};
\node [circle,anchor=west,draw=ublue,minimum width=2.0em] (part2-2) at ([xshift=4.6em,yshift=-2.0em]part1-2.east) {\small {$a_2$}};
\node [anchor=north,minimum width=3.0em] (part2-3) at ([xshift=0.0em,yshift=-2.79em]part2-2.south) {\small {隐藏层}};
\node[anchor=south,minimum height=13em,minimum width=4.0em,draw=ublue,dotted,thick] (part2out) at ([xshift=6.4em,yshift=-8.5em]part1-2.north) {};

%右
\node [circle,anchor=west,draw=ublue,minimum width=2.0em] (part3-1) at ([xshift=10.5em,yshift=0.0em]part1-2.east) {\small {$y$}};
\node [anchor=west,draw=ublue,minimum width=1.5em,minimum height=1.5em] (part3-2) at ([xshift=1.2em]part3-1.east) {\small {$y$}};
\node [anchor=north,minimum width=3.0em] (part3-3) at ([xshift=1.4em,yshift=-4.79em]part3-1.south) {\small {输出层}};
\node[anchor=south,minimum height=13em,minimum width=6.0em,draw=ublue,dotted,thick] (part3out) at ([xshift=13.8em,yshift=-8.5em]part1-2.north) {};

%连线

\draw [->,thick,ublue](part1-1.east)--(part2-1.west);
\draw [->,thick,ublue](part1-1.east)--(part2-2.west);
\draw [->,thick,ublue](part1-2.east)--(part2-1.west);
\draw [->,thick,ublue](part1-2.east)--(part2-2.west);
\draw [->,thick,ublue](part1-3.east)--(part2-1.west);
\draw [->,thick,ublue](part1-3.east)--(part2-2.west);
\draw [->,thick,ublue](part2-1.east)--(part3-1.west);
\draw [->,thick,ublue](part2-2.east)--(part3-1.west);
\draw [->,thick,ublue](part3-1.east)--(part3-2.west);


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