latex合理使用循环和判断选择语句进行绘图的例子

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\begin{frame}[fragile]
\small
由 $4$ 人可构成$2^6 = 64$张 \remph{人际关系图},其中的 $8$ 张图:\\[12pt] %
% %------------------------------------------------------
\setcounter{maincounter}{0}%设置计数器的值
% %------------------------------------------------------
\begin{tikzpicture}[line width = 1.2pt]
\pgfmathsetmacro{\h}{1.4}   %两点的水平间距
\pgfmathsetmacro{\v}{1.4}   %两点的垂直间距
% %------------------------------------------------------
\foreach \r/\c in {0/0,2/0,4/0,6/0,0/2,2/2,4/2,6/2}
{
\stepcounter{maincounter} %增加计数器的值
\setcounter{secondcounter}{0}%设置计数器的值
%定义原点坐标
\coordinate  (P0) at (\r,\c);

\path (P0)  node[circle,fill=red,inner sep=2pt](a){$a$};
\path (a)+(\h,0 )  node[circle,fill=red,inner sep=2pt](b){$b$};
\path (b)+(0,\v )  node[circle,fill=red,inner sep=2pt](c){$c$};
\path (a)+(0,\v )  node[circle,fill=red,inner sep=2pt](d){$d$};
\path ($ (a)!0.5! (b) $)+(0,-0.25)   node (T){ $\left( \themaincounter \right) $};
%画虚线
\foreach \from/\to in {a/b,b/c,c/d,d/a,a/c,b/d}
{
\stepcounter{secondcounter} %增加计数器的值
\ifthenelse{\value{maincounter} < 8}{
\ifthenelse{\value{secondcounter} < \value{maincounter}}
{\draw[blue,very thick] (\from)--(\to) ; }	{\draw[dashed,thin] (\from)--(\to) ;}
}{\draw[dashed,thin] (\from)--(\to) ;}
%------------------------------
}
%------------------------------
\ifthenelse{\value{maincounter} = 8}{\draw[green,very thick] (a)--(b)--(c)--(a) ;  }{}
}
\end{tikzpicture}
\end{frame}