Cfrgtkky

I'm trying to draw a neural network diagram with tikz. I found this code online:

begin{figure}[htp]

centering

begin{tikzpicture}[

plain/.style={

  draw=none,

  fill=none,

  },

net/.style={

  matrix of nodes,

  nodes={

    draw,

    circle,

    inner sep=8.5pt

    },

  nodes in empty cells,

  column sep=0.6cm,

  row sep=-11pt

  },

>=latex

]

matrix[net] (mat)

{

|[plain]| parbox{1cm}{centering Input\layer} & |[plain]| parbox{1cm}{centering Hidden\layer} & |[plain]| parbox{1cm}{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] {Imi} +(-1cm,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] {O1} +(1cm,0);

end{tikzpicture}



caption{ANN diagram for Speed Sign recognition.}

label{fig_m_3}

end{figure}

It produces the following image:

It has 5 input nodes but I want to generalize this drawing by having n nodes in each of the layers. So in input layer, number of node shown will be 4 with vertical '...' in middle, the hidden layer would contain 3 nodes with vertical '...' in middle and output would have 2 nodes with vertical '...' in middle. I want to maintain their conical shape. Something like this:

It is a really bad drawing, sorry about that, one can now imagine how bad I must be with tikz. The dots in middle are actually fully filled, in my drawing they are hollow. Any help or advice would be appreciated.

Here, we a have a festival of foreach:

documentclass[border=0.125cm]{standalone}

usepackage{tikz}

usetikzlibrary{positioning}

begin{document}



tikzset{%

  every neuron/.style={

    circle,

    draw,

    minimum size=1cm

  },

  neuron missing/.style={

    draw=none, 

    scale=4,

    text height=0.333cm,

    execute at begin node=color{black}$vdots$

  },

}



begin{tikzpicture}[x=1.5cm, y=1.5cm, >=stealth]



foreach m/l [count=y] in {1,2,3,missing,4}

  node [every neuron/.try, neuron m/.try] (input-m) at (0,2.5-y) {};



foreach m [count=y] in {1,missing,2}

  node [every neuron/.try, neuron m/.try ] (hidden-m) at (2,2-y*1.25) {};



foreach m [count=y] in {1,missing,2}

  node [every neuron/.try, neuron m/.try ] (output-m) at (4,1.5-y) {};



foreach l [count=i] in {1,2,3,n}

  draw [<-] (input-i) -- ++(-1,0)

    node [above, midway] {$I_l$};



foreach l [count=i] in {1,n}

  node [above] at (hidden-i.north) {$H_l$};



foreach l [count=i] in {1,n}

  draw [->] (output-i) -- ++(1,0)

    node [above, midway] {$O_l$};



foreach i in {1,...,4}

  foreach j in {1,...,2}

    draw [->] (input-i) -- (hidden-j);



foreach i in {1,...,2}

  foreach j in {1,...,2}

    draw [->] (hidden-i) -- (output-j);



foreach l [count=x from 0] in {Input, Hidden, Ouput}

  node [align=center, above] at (x*2,2) {l \ layer};



end{tikzpicture}



end{document}

Although it seems unwise to have n denote the number of nodes in each layer when they could be different and the arrangement of the diagram suggests they are not.

This is a solution where a dot with fully filled with black circle, whose size is changeable via minimum size=xx <dimension>, is defined as a style.

Code

documentclass{article}

usepackage[margin=1cm]{geometry}

usepackage{tikz,pgfplots,pgf}

usetikzlibrary{matrix,shapes,arrows,positioning}

begin{document}



begin{figure}[htp]

centering

begin{tikzpicture}[

plain/.style={

  draw=none,

  fill=none,

  },

dot/.style={draw,shape=circle,minimum size=3pt,inner sep=0,fill=black

  },

net/.style={

  matrix of nodes,

  nodes={

    draw,

    circle,

    inner sep=8.5pt

    },

  nodes in empty cells,

  column sep=0.6cm,

  row sep=-11pt

  },

>=latex

]

matrix[net] (mat)

{

|[plain]| parbox{1cm}{centering Input\layer} 

          & |[plain]| parbox{1cm}{centering Hidden\layer} 

                       & |[plain]| parbox{1cm}{centering Output\layer} \

          & |[plain]|                 \

|[plain]| &            & |[plain]|    \

          & |[plain]|  &              \

|[plain]| & |[dot]|                   \

          & |[plain]|  & |[dot]|      \

|[plain]| & |[dot]|    & |[plain]|    \

|[dot]|   & |[plain]|  & |[dot]|      \

|[dot]|   & |[dot]|    & |[plain]|    \

|[dot]|   & |[plain]|  &              \

|[plain]| &            & |[plain]|    \

          & |[plain]|                 \

};

foreach ai/mi in {2/I1,4/I2,6/I3,12/In}

  draw[<-] (mat-ai-1) -- node[above] {mi} +(-1cm,0);

foreach ai in {2,4,6,12}

{foreach aii/mii in {3/H1,11/Hn}

  draw[->] (mat-ai-1) -- (mat-aii-2) node[yshift=0.6cm] {mii};

}

foreach ai in {3,11}

{  draw[->] (mat-ai-2) -- (mat-4-3);

  draw[->] (mat-4-3) -- node[above] {O1} +(1cm,0);}

foreach ai in {3,11}

{  draw[->] (mat-ai-2) -- (mat-10-3);

  draw[->] (mat-10-3) -- node[above] {On} +(1cm,0);}

end{tikzpicture}



caption{ANN diagram for Speed Sign recognition.}

label{fig_m_3}

end{figure}



end{document}

I know that this is an old question. But I just found this code by Kjell Magne Fauske on TeXample about a neural network and I think it can be helpful to future readers since it's easy to modify.

documentclass{article}



usepackage{tikz}

begin{document}

pagestyle{empty}



deflayersep{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 neuron}=[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 layer nodes

    foreach name / y in {1,...,5}

        path[yshift=0.5cm]

            node[hidden neuron] (H-name) at (layersep,-y cm) {};



    % Draw the output layer node

    node[output neuron,pin={[pin edge={->}]right:Output}, right of=H-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 (H-dest);



    % Connect every node in the hidden layer with the output layer

    foreach source in {1,...,5}

        path (H-source) edge (O);



    % Annotate the layers

    node[annot,above of=H-1, node distance=1cm] (hl) {Hidden layer};

    node[annot,left of=hl] {Input layer};

    node[annot,right of=hl] {Output layer};

end{tikzpicture}

% End of code

end{document}

I found this package neuralnetwork, made by Mark K Cowan, which makes drawing neural networks pretty simple. For example:

documentclass{standalone}



usepackage{neuralnetwork}



begin{document}

    begin{neuralnetwork}[height=4]

        newcommand{x}[2]{$x_#2$}

        newcommand{y}[2]{$hat{y}_#2$}

        newcommand{hfirst}[2]{small $h^{(1)}_#2$}

        newcommand{hsecond}[2]{small $h^{(2)}_#2$}

        inputlayer[count=3, bias=true, title=Input\layer, text=x]

        hiddenlayer[count=4, bias=false, title=Hidden\layer 1, text=hfirst] linklayers

        hiddenlayer[count=3, bias=false, title=Hidden\layer 2, text=hsecond] linklayers

        outputlayer[count=2, title=Output\layer, text=y] linklayers

    end{neuralnetwork}

end{document}