# Diagram of an artificial neural network

I need draw some picture, but I don't know how do that.

First, the simple graph with basic shapes, arrow,....

And then, draw a picture with math symbol or equation in math environment. Like that:

Please help me draw two picture. And if you don't mind, please show me some tools which can help me draw easily and generate to latex code, or some document help me learnt quickly. Thanks for your help

One possibility; the first diagram was drawn using a matrix; the second one, using chains:

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{matrix,chains,positioning,decorations.pathreplacing,arrows}

\begin{document}

\begin{tikzpicture}[
plain/.style={
draw=none,
fill=none,
},
net/.style={
matrix of nodes,
nodes={
draw,
circle,
inner sep=10pt
},
nodes in empty cells,
column sep=2cm,
row sep=-9pt
},
>=latex
]
\matrix[net] (mat)
{
|[plain]| \parbox{1.3cm}{\centering Input\\layer} & |[plain]| \parbox{1.3cm}{\centering Hidden\\layer} & |[plain]| \parbox{1.3cm}{\centering Output\\layer} \\
& |[plain]| \\
|[plain]| & \\
& |[plain]| \\
|[plain]| & |[plain]| \\
& & \\
|[plain]| & |[plain]| \\
& |[plain]| \\
|[plain]| & \\
& |[plain]| \\    };
\foreach \ai [count=\mi ]in {2,4,...,10}
\draw[<-] (mat-\ai-1) -- node[above] {Input \mi} +(-2cm,0);
\foreach \ai in {2,4,...,10}
{\foreach \aii in {3,6,9}
\draw[->] (mat-\ai-1) -- (mat-\aii-2);
}
\foreach \ai in {3,6,9}
\draw[->] (mat-\ai-2) -- (mat-6-3);
\draw[->] (mat-6-3) -- node[above] {Ouput} +(2cm,0);
\end{tikzpicture}

\begin{tikzpicture}[
init/.style={
draw,
circle,
inner sep=2pt,
font=\Huge,
join = by -latex
},
squa/.style={
draw,
inner sep=2pt,
font=\Large,
join = by -latex
},
start chain=2,node distance=13mm
]
\node[on chain=2]
(x2) {$x_2$};
\node[on chain=2,join=by o-latex]
{$w_2$};
\node[on chain=2,init] (sigma)
{$\displaystyle\Sigma$};
\node[on chain=2,squa,label=above:{\parbox{2cm}{\centering Activate \\ function}}]
{$f$};
\node[on chain=2,label=above:Output,join=by -latex]
{$y$};
\begin{scope}[start chain=1]
\node[on chain=1] at (0,1.5cm)
(x1) {$x_1$};
\node[on chain=1,join=by o-latex]
(w1) {$w_1$};
\end{scope}
\begin{scope}[start chain=3]
\node[on chain=3] at (0,-1.5cm)
(x3) {$x_3$};
\node[on chain=3,label=below:Weights,join=by o-latex]
(w3) {$w_3$};
\end{scope}
\node[label=above:\parbox{2cm}{\centering Bias \\ $b$}] at (sigma|-w1) (b) {};

\draw[-latex] (w1) -- (sigma);
\draw[-latex] (w3) -- (sigma);
\draw[o-latex] (b) -- (sigma);

\draw[decorate,decoration={brace,mirror}] (x1.north west) -- node[left=10pt] {Inputs} (x3.south west);
\end{tikzpicture}

\end{document}


• Thanks. can you introduce me some document or software about tikz? Commented Sep 10, 2013 at 6:20
• @phuong the pgf manual has numerous examples and some nice inroductory tutorials: mirrors.ctan.org/graphics/pgf/base/doc/generic/pgf/… There's also a shorter document: cremeronline.com/LaTeX/minimaltikz.pdf (I've never used this last one). Commented Sep 10, 2013 at 12:55
• Thanks you for your document. It's very useful. I just need 1 requirement. on the second graph, I want to remove a vertical line of circle. I tried hard but not done. Would you please help me again? Commented Sep 10, 2013 at 17:01
• @phuong Sure! The problem is I am not sure exactly which line you are referring to. Do you want to suppress the arrow going from "Bias b" to the "Sigma"? Commented Sep 10, 2013 at 17:49
• No, not bias. I want to remove circles between x_1 & w_1; x_2 &w_2; x_3 and W_3. You can see again my graph on question to know exactly. Commented Sep 11, 2013 at 6:09