figure-bi-RNN.tex

%--------------------------------------------------------------------------------

    \begin{tikzpicture}
        %\newlength{\base}
        \setlength{\base}{0.9cm}

        \tikzstyle{rnnnode} = [rounded corners=1pt,minimum size=0.5\base,draw,inner sep=0pt,outer sep=0pt]
        \tikzstyle{wordnode} = [font=\tiny]

        % RNN translation model
        \begin{scope}[local bounding box=RNNMT]
            % RNN Encoder
            \coordinate (eemb0) at (0,0);
            \foreach \x [count=\y from 0] in {1,2,...,10}
                \node[rnnnode,minimum height=0.5\base,fill=green!30!white,anchor=west] (eemb\x) at ([xshift=0.4\base]eemb\y.east) {};
            \foreach \x in {1,2,...,10}
                \node[rnnnode,fill=blue!30!white,anchor=south] (backenc\x) at ([yshift=0.5\base]eemb\x.north) {};
            \foreach \x in {1,2,...,10}
                \node[rnnnode,fill=blue!30!white,anchor=south] (enc\x) at ([yshift=0.5\base]backenc\x.north) {};
            \node[wordnode,left=0.4\base of enc1] (init) {$0$};
            \node[wordnode,right=0.4\base of backenc10] (backinit) {$0$};
            \node [rnnnode,fill=purple!30!white] at (enc10) {};
            \node [rnnnode,fill=purple!30!white] at (backenc1) {};

            \node[wordnode,below=0pt of eemb1] () {你};
            \node[wordnode,below=0pt of eemb2] () {知道};
            \node[wordnode,below=0pt of eemb3] () {去};
            \node[wordnode,below=0pt of eemb4] () {北京站};
            \node[wordnode,below=0pt of eemb5] () {的};
            \node[wordnode,below=0pt of eemb6] () {路};
            \node[wordnode,below=0pt of eemb7] () {怎么};
            \node[wordnode,below=0pt of eemb8] () {走};
            \node[wordnode,below=0pt of eemb9] () {吗};
            \node[wordnode,below=0pt of eemb10] () {$\langle$eos$\rangle$};

            % RNN Decoder
            \foreach \x in {1,2,...,10}
                \node[rnnnode,minimum height=0.5\base,fill=green!30!white,anchor=south] (demb\x) at ([yshift=1.5\base]enc\x.north) {};
            \foreach \x in {1,2,...,10}
                \node[rnnnode,fill=blue!30!white,anchor=south] (dec\x) at ([yshift=0.5\base]demb\x.north) {};
            \foreach \x in {1,2,...,10}
                \node[rnnnode,minimum height=0.5\base,fill=red!30!white,anchor=south] (softmax\x) at ([yshift=0.5\base]dec\x.north) {};

            % Decoder input words
            \node[wordnode,below=0pt of demb1] (decwordin) {$\langle$eos$\rangle$};
            \ExtractX{$(demb2.south)$}
            \ExtractY{$(decwordin.base)$}
            \node[wordnode,anchor=base] () at (\XCoord,\YCoord) {Do};
            \ExtractX{$(demb3.south)$}
            \ExtractY{$(decwordin.base)$}
            \node[wordnode,anchor=base] () at (\XCoord,\YCoord) {you};
            \ExtractX{$(demb4.south)$}
            \ExtractY{$(decwordin.base)$}
            \node[wordnode,anchor=base] () at (\XCoord,\YCoord) {know};
            \ExtractX{$(demb5.south)$}
            \ExtractY{$(decwordin.base)$}
            \node[wordnode,anchor=base] () at (\XCoord,\YCoord) {the};
            \ExtractX{$(demb6.south)$}
            \ExtractY{$(decwordin.base)$}
            \node[wordnode,anchor=base] () at (\XCoord,\YCoord) {way};
            \ExtractX{$(demb7.south)$}
            \ExtractY{$(decwordin.base)$}
            \node[wordnode,anchor=base] () at (\XCoord,\YCoord) {to};
            \ExtractX{$(demb8.south)$}
            \ExtractY{$(decwordin.base)$}
            \node[wordnode,anchor=base] () at (\XCoord,\YCoord) {Beijing};
            \ExtractX{$(demb9.south)$}
            \ExtractY{$(decwordin.base)$}
            \node[wordnode,anchor=base] () at (\XCoord,\YCoord) {Railway};
            \ExtractX{$(demb10.south)$}
            \ExtractY{$(decwordin.base)$}
            \node[wordnode,anchor=base] () at (\XCoord,\YCoord) {Station};

            % Decoder output words
            \node[wordnode,above=0pt of softmax1] (decwordout) {Do};
            \ExtractX{$(softmax2.north)$}
            \ExtractY{$(decwordout.base)$}
            \node[wordnode,anchor=base] () at (\XCoord,\YCoord) {you};
            \ExtractX{$(softmax3.north)$}
            \ExtractY{$(decwordout.base)$}
            \node[wordnode,anchor=base] () at (\XCoord,\YCoord) {know};
            \ExtractX{$(softmax4.north)$}
            \ExtractY{$(decwordout.base)$}
            \node[wordnode,anchor=base] () at (\XCoord,\YCoord) {the};
            \ExtractX{$(softmax5.north)$}
            \ExtractY{$(decwordout.base)$}
            \node[wordnode,anchor=base] () at (\XCoord,\YCoord) {way};
            \ExtractX{$(softmax6.north)$}
            \ExtractY{$(decwordout.base)$}
            \node[wordnode,anchor=base] () at (\XCoord,\YCoord) {to};
            \ExtractX{$(softmax7.north)$}
            \ExtractY{$(decwordout.base)$}
            \node[wordnode,anchor=base] () at (\XCoord,\YCoord) {Beijing};
            \ExtractX{$(softmax8.north)$}
            \ExtractY{$(decwordout.base)$}
            \node[wordnode,anchor=base] () at (\XCoord,\YCoord) {Railway};
            \ExtractX{$(softmax9.north)$}
            \ExtractY{$(decwordout.base)$}
            \node[wordnode,anchor=base] () at (\XCoord,\YCoord) {Station};
            \ExtractX{$(softmax10.north)$}
            \ExtractY{$(decwordout.base)$}
            \node[wordnode,anchor=base] () at (\XCoord,\YCoord) {$\langle$eos$\rangle$};

            % Connections
            \draw[-latex'] (init.east) to (enc1.west);
            \draw[-latex'] (backinit.west) to (backenc10.east);
            \foreach \x in {1,2,...,10}
                \draw[-latex'] (eemb\x) to (backenc\x);
            \foreach \x in {1,2,...,10}
                \draw[-latex'] (eemb\x.north) to [out=15,in=-15] (enc\x.south);
            \foreach \x in {1,2,...,10}
                \draw[-latex'] (demb\x) to (dec\x);
            \foreach \x in {1,2,...,10}
                \draw[-latex'] (dec\x.north) to ([yshift=0.5\base]dec\x.north);
            \foreach \x [count=\y from 2] in {1,2,...,9}
            {
                \draw[-latex'] (enc\x.east) to (enc\y.west);
                \draw[-latex'] (dec\x.east) to (dec\y.west);
            }
            \def\y{0}
            \foreach \x in {10,9,...,2}
            {
                \pgfmathtruncatemacro{\y}{\x - 1}
                \draw[-latex'] (backenc\x.west) to (backenc\y.east);
            }
            \coordinate (bridge) at ([yshift=-1.2\base]demb2);
            \draw[-latex'] (enc10.north) .. controls +(north:0.7\base) and +(east:1.5\base) .. (bridge) .. controls +(west:2.5\base) and +(west:0.6\base) .. (dec1.west);
            \draw[-latex'] (backenc1) to [out=180,in=180] (dec1.west);

            % Backward RNN
            \begin{pgfonlayer}{background}
                \node[draw=red,thick,densely dashed,inner sep=5pt] [fit = (backinit) (backenc1) (backenc10)] (backrnn) {};
            \end{pgfonlayer}
            \node[font=\scriptsize,anchor=south] (backrnnlabel) at ([xshift=-0.5\base,yshift=\base]backrnn.north east) {反向RNN};
            \draw[->,dashed] (backrnnlabel.south) to ([xshift=-0.5\base]backrnn.north east);
        \end{scope}
    \end{tikzpicture}