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\begin{tikzpicture}
\draw[name path=ellipse,thick] (0,0) circle[x radius = 2, y radius = 1];
\node[rectangle,minimum size=0.1em,inner sep=2pt,fill=red] (p1) at (0.2,0.5) {};
\node[rectangle,minimum size=0.1em,inner sep=2pt,fill=red] (p2) at (0.3,0.6) {};
\node[rectangle,minimum size=0.1em,inner sep=2pt,fill=red] (p3) at (0.1,-0.1) {};
\node[rectangle,minimum size=0.1em,inner sep=2pt,fill=red] (p4) at (0.4,0) {};
\node[rectangle,minimum size=0.1em,inner sep=2pt,fill=red] (p5) at (0.5,0.3) {};
\node[rectangle,minimum size=0.1em,inner sep=2pt,fill=red] (p6) at (0.6,0.1) {};
\node[rectangle,minimum size=0.1em,inner sep=2pt,fill=red] (p7) at (0.7,-0.1) {};
\node[rectangle,minimum size=0.1em,inner sep=2pt,fill=red] (p8) at (-1.2,0.4) {};
\node[rectangle,minimum size=0.1em,inner sep=2pt,fill=red] (p9) at (-1.0,-0.3) {};
\node[rectangle,minimum size=0.1em,inner sep=2pt,fill=red] (p10) at (-0.1,-0.8) {};

\begin{pgfonlayer}{background}
{
\node [rectangle,inner sep=0.4em,draw,blue] [fit = (p1) (p2) (p3) (p4) (p5) (p6)] (area) {};
}
\end{pgfonlayer}

\draw [->] (2.5,-0.7) -- (1.8,-0.5) node [pos=0,right] {\scriptsize{模型参数解空间}};

{
\draw [->] (2.0,0.7) -- (area.20) node [pos=0,right] {\scriptsize{优质解高密度区域(预训练)}};
}
{
\draw [->] (-2.0,0.7) -- (p8.west) node [pos=0,left] {\scriptsize{游离的解}};
}

\end{tikzpicture}
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