在科研论文写作中，有时候为了横向、纵向对比或者节省空间，我们需要画子图，在MATLAB中可以通过subplot命令来实现。在Latex中有以下几种方法进行子图的绘制：
- 使用subfig宏包（有可能与hyperref宏包冲突，推荐使用subcaption宏包），主要格式为：
\begin{figure}\subfloat[]{}\subfloat[]{}\\\subfloat[]{}\subfloat[]{}\end{figure}
使用subcaption宏包，主要格式为：
\begin{figure}\subcaptionbox{}{}\subcaptionbox{}{}\\\subcaptionbox{}{}\subcaptionbox{}{}\end{figure}
使用groupplot宏包，主要格式为：
\begin{figure}\centering\begin{tikzpicture}\begin{groupplot}\nextgroupplot\addplot {x};\nextgroupplot\end{groupplot}\end{tikzpicture}\end{figure}
使用matrix宏包，主要格式为：
\begin{figure}\centering\begin{tikzpicture}\matrix{\begin{axis}\addplot {x};\end{axis}\begin{axis}\addplot {x};\end{axis}}\end{tikzpicture}\end{figure}
下面给出上述各种情况的具体代码实现以及示意图：
- 使用subfig宏包
代码如下：
\documentclass{article}\usepackage[dvipdfm]{graphicx}\def\pgfsysdriver{pgfsys-dvipdfmx.def}\usepackage{tikz}\usepackage{pgfplots}\usepackage{subfig}%使用子图包，可能与hyperref冲突\usepackage{float}\usepackage{cite}\usepackage[colorlinks,dvipdfm,pdfpagemode=UseOutlines,pdfstartview=FitH,anchorcolor=green,citecolor=blue,linkcolor=red,hyperindex=true,pagebackref,bookmarksnumbered,bookmarksopenlevel=2,colorlinks]{hyperref}\pgfplotsset{width=6cm,compat=1.15}\begin{document}\begin{figure}\begin{center}\subfloat[\label{subfig1}]{\begin{tikzpicture}\begin{axis}[legend columns=-1,%the legend are plotted horizontallylegend entries={$x$},legend to name=named,% stored in named, not plotted in the figuretitle={subfig1},]\addplot {x};\label{curvex}\end{axis}\end{tikzpicture}\label{subfig2}}\subfloat[]{\begin{tikzpicture}\begin{axis}[title={subfig2}]\addplot {x};\end{axis}\end{tikzpicture}\label{subfig2}}\end{center}\caption{\hspace{1em}Two subfigures.}\label{f1}\end{figure}As depicted in Figures~\ref{subfig1} and \ref{subfig2}, the subfigures of Figure~\ref{f1}, \ref{curvex} represents function $f(x)=x$.\end{document}
使用subcaption宏包
代码如下：
\documentclass{article}\usepackage[dvipdfm]{graphicx}\def\pgfsysdriver{pgfsys-dvipdfmx.def}\usepackage{tikz}\usepackage{pgfplots}%\usepackage{subfig}\usepackage[hypcap=true,labelsep=period,font=small]{caption}% 图的标题设置Fig.\usepackage[hypcap=true]{subcaption}%用于画子图 可以适配hyperref包\usepackage{float}\usepackage[colorlinks,dvipdfm,pdfpagemode=UseOutlines,pdfstartview=FitH,anchorcolor=green,citecolor=blue,linkcolor=red,hyperindex=true,pagebackref,bookmarksnumbered,bookmarksopenlevel=2,colorlinks]{hyperref}\pgfplotsset{width=6cm,compat=1.15}\begin{document}\begin{figure}\begin{center}\subcaptionbox{\label{subfig1}}{\begin{tikzpicture}\begin{axis}[legend columns=-1,%the legend are plotted horizontallylegend entries={$x$},legend to name=named,% stored in namedtitle={subfig1},]\addplot {x};\label{curvex}\end{axis}\end{tikzpicture}}\subcaptionbox{\label{subfig2}}{\begin{tikzpicture}\begin{axis}[title={subfig2}]\addplot {x};\end{axis}\end{tikzpicture}}\end{center}\caption{\hspace{1em}Two subfigures.}\label{f1}\end{figure}As depicted in Figures~\ref{subfig1} and \ref{subfig2}, the subfigures of Figure~\ref{f1}, \ref{curvex} represents function $f(x)=x$.\end{document}
使用groupplot宏包
代码如下：
\documentclass{article}\usepackage[dvipdfm]{graphicx}\def\pgfsysdriver{pgfsys-dvipdfmx.def}\usepackage{tikz}\usepackage{pgfplots}\pgfplotsset{width=7cm,compat=1.15}\usepgfplotslibrary{groupplots}\usepackage{caption}\usepackage{subcaption}\usepackage[colorlinks,dvipdfm,pdfpagemode=UseOutlines,pdfstartview=FitH,anchorcolor=green,citecolor=blue,linkcolor=red,hyperindex=true,pagebackref,bookmarksnumbered,bookmarksopenlevel=2,colorlinks]{hyperref}\begin{document}\begin{figure}[htb]\centering\begin{tikzpicture}\begin{groupplot}[group style={group name=my plots,group size=2 by 2,xlabels at=edge bottom,xlabels at=all,ylabels at=edge left,x descriptions at=edge bottom,},footnotesize,width=6cm,height=6cm,%xlabel=$x$,ylabel=$f(x)$,]\nextgroupplot\addplot {x};\node [text width=1em,anchor=north west] at (rel axis cs: 0,1){\subcaption{\label{f11}}};%<- changed\nextgroupplot\addplot {x^2};\nextgroupplot\addplot {x^3};\nextgroupplot\addplot {x^4};\end{groupplot}\end{tikzpicture}\caption{\hspace{1em}Four subfigures.}\label{f1}\end{figure}How to refer to subfigure~\ref{f11} in Figure~\ref{f1}.\end{document}
使用matrix宏包
代码如下：
\documentclass{article}\usepackage[dvipdfm]{graphicx}\def\pgfsysdriver{pgfsys-dvipdfmx.def}\usepackage{tikz}\usepackage{pgfplots}\pgfplotsset{width=7cm,compat=1.15}\usepgfplotslibrary{groupplots}\usetikzlibrary{matrix}\usepackage{caption}\usepackage{subcaption}\usepackage[colorlinks,dvipdfm,pdfpagemode=UseOutlines,pdfstartview=FitH,anchorcolor=green,citecolor=blue,linkcolor=red,hyperindex=true,pagebackref,bookmarksnumbered,bookmarksopenlevel=2,colorlinks]{hyperref}\begin{document}\begin{figure}[htb]\centering\begin{tikzpicture}\pgfplotsset{small}\matrix {\begin{axis}[ylabel={$f(x)=x$},ylabel style={font=\small}]\addplot {x};\node [text width=1em,anchor=north west] at (rel axis cs: 0,1){\subcaption{\label{f11}}};%<- changed\end{axis}&% differently large labels are aligned automatically:\begin{axis}[ylabel={$f(x)=x^2$},ylabel style={font=\small}]\addplot {x^2};\end{axis}\\\begin{axis}[ylabel={$f(x)=x^3$},ylabel style={font=\small},xlabel=$x$,xlabel style={font=\small}]\addplot {x^3};\end{axis}&\begin{axis}[ylabel={$f(x)=x^4$},ylabel style={font=\small},xlabel=$x$,xlabel style={font=\small}]\addplot {x^4};\end{axis}\\};\end{tikzpicture}\caption{\hspace{1em}Four subfigures.}\label{f1}\end{figure}How to refer to subfigure~\ref{f11} in Figure~\ref{f1}.\end{document}
Note: 第三种和第四种方法不适合需要单独引用每一个子图的情况，比较适合把四张图看成一个整体的情况。
参考文献：
[1] pgfplots manual: /pgfplots.pdf
本科舍友不幸得了黑色素癌, 在此恳求大家能给予帮助，在此谢谢大家！以下是水滴筹的链接：
/cf/contribute/7d975cfc-e508-4549-acb1-5a31ceb759a1?channel=wx_charity_pyq&source=7hEPKZfbC7kzc7ndTKDD6cZriDdYH4TQ&forwardFrom=5&sharedv=
今天发现该链接已经提现了，但是已筹金额未达预期，期望各位通过左下角的微信扫码进行捐款，我将悉数给予舍友。再次感谢大家的帮助！
