figure-code-back-propagation-1.tex

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 \begin{tcolorbox}
[bicolor,sidebyside,width=13cm,righthand width=4cm,size=title,frame engine=empty,
 colback=blue!10!white,colbacklower=black!5!white]
 {\scriptsize
\begin{tabbing}
\texttt{XTensor x, y, gold, h[5], w[5], s[5];} \\
\texttt{XTensor dh[5], dw[5], ds[5];} \\
\texttt{...} // 前向过程 \\
\texttt{h[0] = x;} \\
\texttt{y = h[4];} \\


\texttt{} \\
\texttt{CrossEntropyBackward(dh[4], y, gold);} \\
\texttt{SoftmaxBackward(y, s[4], dh[4], ds[4]);}\\
\texttt{MMul(h[3], {\scriptsize X\_TRANS}, ds[4], {\scriptsize X\_NOTRANS}, dw[4]);}\\
\texttt{MMul(ds[4], {\scriptsize X\_NOTRANS}, w[4], {\scriptsize X\_RANS}, dh[3]);}\\



\texttt{} \\
\texttt{dh[2] = dh[3];}\\
\texttt{ReluBackward(h[2], s[2], dh[2], ds[2]);}\\
\texttt{MMul(h[1], {\scriptsize X\_TRANS}, ds[2], {\scriptsize X\_NOTRANS}, dw[2]);}\\
\texttt{MMul(ds[2], {\scriptsize X\_NOTRANS}, w[2], {\scriptsize X\_TRANS}, dh[2]);}\\



\texttt{} \\
\texttt{dh[1] = dh[1] + dh[3];}\\



\texttt{...} // 继续反向传播 \\
\texttt{} \\
\texttt{for(unsigned i = 0; i < 5; i++)\{} \\
\texttt{} \ \ \ \ ... // 通过{\texttt{dw[i]}}访问参数的梯度\\
\texttt{\}}


\end{tabbing}
}
\tcblower
\begin{center}
\begin{tikzpicture}


\node [anchor=south,draw,rounded corners,inner sep=2pt,minimum width=8em,minimum height=1.2em,fill=red!30!white,blur shadow={shadow xshift=1pt,shadow yshift=-1pt}] (h1) at (0,0) {\scriptsize{x (input)}};
\node [anchor=south,draw,rounded corners,inner sep=2pt,minimum width=8em,minimum height=1.2em,fill=green!30!white,blur shadow={shadow xshift=1pt,shadow yshift=-1pt}] (h2) at ([yshift=1.5em]h1.north) {\scriptsize{h1 = Relu(x * w1)}};
\node [anchor=south,draw,rounded corners,inner sep=2pt,minimum width=8em,minimum height=1.2em,fill=green!30!white,blur shadow={shadow xshift=1pt,shadow yshift=-1pt}] (h3) at ([yshift=1.5em]h2.north) {\scriptsize{h2 = Relu(h1 * w2)}};
\node [anchor=south,draw,rounded corners,inner sep=2pt,minimum width=8em,minimum height=1.2em,fill=green!30!white,blur shadow={shadow xshift=1pt,shadow yshift=-1pt}] (h4) at ([yshift=1.5em]h3.north) {\scriptsize{h3 = h2 + h1}};

{\draw [->,very thick] (h1.north) -- (h2.south);}
{\draw [->,very thick] (h2.north) -- (h3.south);}
{\draw [->,very thick] (h3.north) -- (h4.south);}
{\draw [->,very thick,rounded corners] (h2.east) -- ([xshift=0.5em]h2.east) -- ([xshift=0.5em,yshift=0.5em]h3.north east) -- ([xshift=-2em,yshift=0.5em]h3.north east) -- ([xshift=-2em,yshift=1.5em]h3.north east);}

\node [anchor=south,draw,rounded corners,inner sep=2pt,minimum width=8.0em,minimum height=1.2em,fill=red!30!white,blur shadow={shadow xshift=1pt,shadow yshift=-1pt}] (slayer) at ([yshift=1.5em]h4.north) {\tiny{h4 = Softmax(h3 * w4) (output)}};
\node [anchor=south] (losslabel) at (slayer.north) {\scriptsize{\textbf{Cross Entropy Loss}}};

{\draw [->,very thick] (h4.north) -- (slayer.south);}

\end{tikzpicture}
\end{center}
\end{tcolorbox}

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