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% Copyright (C) 2021 by Carlos Cardoso Dias <carlosdias.dev@gmail.com>
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% This work may be distributed and/or modified under the
% conditions of the LaTeX Project Public License, either version 1.3
% of this license or (at your option) any later version.
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%   http://www.latex-project.org/lppl.txt
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% This work has the LPPL maintenance status `maintained'.
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% The Current Maintainer of this work is Carlos Cardoso Dias.
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% This work consists of the files nndraw.dtx and nndraw.ins
% and the derived filebase nndraw.sty.
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% \iffalse
%<*driver>
\ProvidesFile{nndraw.dtx}
%</driver>
%<package>\NeedsTeXFormat{LaTeX2e}[1999/12/01]
%<package>\ProvidesPackage{nndraw}
%<*package>
    [2021/06/22 1.0 nndraw is a LaTeX package which provides utilities to draw neural networks.]
%</package>
%
%<*driver>
\documentclass{ltxdoc}
\usepackage{nndraw}[2021/06/22]
\EnableCrossrefs
\CodelineIndex
\RecordChanges
\begin{document}
  \DocInput{nndraw.dtx}
  \PrintChanges
  \PrintIndex
\end{document}
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% \changes{1.0}{2021/06/22}{Converted to DTX file}
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% \DoNotIndex{\newcommand,\newenvironment}
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% \providecommand*{\url}{\texttt}
% \GetFileInfo{nndraw.dtx}
% \title{The \textsf{nndraw} package}
% \author{Carlos Cardoso Dias \\ \url{carlosdias.dev@gmail.com}}
% \date{\fileversion~from \filedate}
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% \maketitle
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% \section{Introduction}
%
\textbf{nndraw} is a \LaTeX package which provides utilities to draw neural networks in an efficient way.
Currently this package provides utilities to draw fully connected feedforward neural networks with an arbitrary
number of layers described inside the `fullyconnectednn` environment using the command `nnlayer`.
%
% \section{Usage}
%
An example of usage is shown below, in this example, a fully connected feedforward
deep neural network is provided with two inputs in the first layer, one hidden layer
with four neurons and one output layer with one output. This example shows how easy it is
to customize the presence/absence of biases in any layer as well as its position.

\begin{verbatim}
\begin{fullyconnectednn}[biasy = -4.5,
                         titley = 1,
                         inout = false]
    \nnlayer[title = Input layer]{2}
    \nnlayer[title = Hidden layer]{4}
    \nnlayer[title = Ouput layer, hasbias = false]{1}
\end{fullyconnectednn}
\end{verbatim}

\noindent Which is drawn as

\begin{fullyconnectednn}[biasy = -4.5,
                         titley = 1,
                         inout = false]
    \nnlayer[title = Input layer]{2}
    \nnlayer[title = Hidden layer]{4}
    \nnlayer[title = Ouput layer, hasbias = false]{1}
\end{fullyconnectednn}
%
%
% \StopEventually{}
%
% \section{Implementation}
%
% \iffalse
%<*package>
% \fi
%
%    \begin{macrocode}
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{nndraw}[2021/06/20 Neural Networks Draw LaTeX package]
\RequirePackage{tikz}
\pgfdeclarelayer{back}
\pgfsetlayers{back,main}
%    \end{macrocode}
%
% \begin{macro}{\nnlayerNoText}
%    \begin{macrocode}
\newcommand\nnlayerNoText[1]{}
%    \end{macrocode}
% \end{macro}
%
%    \begin{macrocode}
\newif\ifnnlayerHasBias
\pgfkeys{
 /nnlayer/.is family, /nnlayer,
 default/.style = {title = , text = \nnlayerNoText, hasbias = true, bias = , color = , biascolor = },
 title/.estore in = \nnlayerTitle,
 text/.store in = \nnlayerText,
 hasbias/.is if = nnlayerHasBias,
 bias/.estore in = \nnlayerBias,
 color/.estore in = \nnlayerColor,
 biascolor/.estore in = \nnlayerBiasColor,
}
\newcounter{numlayers}
\newcounter{nninputlayer}
\newcounter{lastnnsize}
\tikzstyle{neuron}=[circle, minimum size=6mm, fill=gray!70]
\tikzstyle{neuron_connection}=[->, shorten >=1pt, gray!70]
%    \end{macrocode}
%
% \begin{macro}{\nnlayer}
%    \begin{macrocode}
\newcommand\nnlayer[2][]{
    \pgfkeys{/nnlayer, default, #1}
    \node[text width = \fullyconnectednnTextWidth, align = center] at (\fullyconnectednnLayersep *
    \thenumlayers,\fullyconnectednnTitleY) {\nnlayerTitle};
    \if\thenninputlayer0
        \setcounter{nninputlayer}{#2}
    \fi
    \foreach \i in {1,...,#2}
    {
        \node[neuron, yshift=(#2 - \thenninputlayer)*5 mm, fill=\nnlayerColor] (\thenumlayers-\i) at (\thenumlayers * \fullyconnectednnLayersep,-\i) {\nnlayerText{\i}};
    }
    \if\thelastnnsize0
    \else
        \ifnnlayerHasBias
            \node[neuron, yshift=5mm, fill=\nnlayerBiasColor] (bias-\thenumlayers) at (\thenumlayers * \fullyconnectednnLayersep -\fullyconnectednnLayersep + \fullyconnectednnBiasX, \fullyconnectednnBiasY) {\nnlayerBias};
        \fi
        \begin{pgfonlayer}{back}
%    \end{macrocode}
% node connections
%    \begin{macrocode}
            \foreach \i in {1,...,\thelastnnsize}
            {
                \foreach \j in {1,...,#2}
                {
                    \draw[neuron_connection] (\the\numexpr\thenumlayers-1\relax-\i) -- (\thenumlayers-\j);
                }
            }
%    \end{macrocode}
% bias connections
%    \begin{macrocode}
            \ifnnlayerHasBias
                \foreach \j in {1,...,#2}
                {
                    \draw[neuron_connection] (bias-\thenumlayers) -- (\thenumlayers-\j);
                }
            \fi
        \end{pgfonlayer}
    \fi
    \setcounter{lastnnsize}{#2}
    \stepcounter{numlayers}
}
%    \end{macrocode}
% \end{macro}
%
%    \begin{macrocode}
\newif\iffullyconnectednnInout
\pgfkeys{
 /fullyconnectednn/.is family, /fullyconnectednn,
 default/.style = {input = \nnlayerNoText, output = \nnlayerNoText, layersep = 3, biasx = 0.75, biasy = -8.75, titley = 0.75, inout = true, text width = 2cm},
 input/.store in = \fullyconnectednnInput,
 output/.store in = \fullyconnectednnOutput,
 layersep/.estore in = \fullyconnectednnLayersep,
 biasx/.estore in = \fullyconnectednnBiasX,
 biasy/.estore in = \fullyconnectednnBiasY,
 titley/.estore in = \fullyconnectednnTitleY,
 inout/.is if = fullyconnectednnInout,
 text width/.estore in = \fullyconnectednnTextWidth,
}
%    \end{macrocode}
%
% \begin{environment}{fullyconnectednn}
%    \begin{macrocode}
\newenvironment{fullyconnectednn}[1][]
    {
    \pgfkeys{/fullyconnectednn, default, #1}
    \begin{center}
    \begin{tikzpicture}
    \setcounter{numlayers}{0}
    \setcounter{nninputlayer}{0}
    \setcounter{lastnnsize}{0}
    }
    {
    \iffullyconnectednnInout
    \begin{pgfonlayer}{back}
%    \end{macrocode}
% Inputs
%    \begin{macrocode}
    \foreach \i in {1,...,\thenninputlayer}
    {            
        \draw[<-, shorten <=1pt] (0-\i) -- ++(-1,0) node[left]{\fullyconnectednnInput{\i}};
    }
     
%    \end{macrocode}
% Outputs
%    \begin{macrocode}
    \foreach \i in {1,...,\thelastnnsize}
    {
        \draw[->, shorten <=1pt] (\the\numexpr\thenumlayers-1\relax-\i) -- ++(1,0) node[right]{\fullyconnectednnOutput{\i}};
    }
    \end{pgfonlayer}
    \fi
    \end{tikzpicture}
    \end{center}
    }
%    \end{macrocode}
% \end{environment}
%

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