输入任务包平均价格、聚类中心位置，任务包内会员的指标。 这句话太长，想让他分为两行，如下：
输入任务包平均价格、聚类中心位置，
任务包内会员的指标。
\documentclass[UTF8,a4paper]{ctexart}
\usepackage{graphicx}
\usepackage{tikz}
\usetikzlibrary{shapes.geometric, arrows}
\begin{document}
\begin{figure}[h]
\centering
\thispagestyle{empty}
% 流程图定义基本形状
\tikzstyle{startstop} = [rectangle, rounded corners, minimum width = 2cm, minimum height=1cm,text centered, draw = black, fill = red!40]
\tikzstyle{io} = [trapezium, trapezium left angle=70, trapezium right angle=110, minimum width=2cm, minimum height=1cm, text centered, draw=black, fill = blue!40]
\tikzstyle{process} = [rectangle, minimum width=3cm, minimum height=1cm, text centered, draw=black, fill = yellow!50]
\tikzstyle{decision} = [diamond, aspect = 3, text centered, draw=black, fill = green!30]
\tikzstyle{point}=[coordinate]
% 箭头形式
\tikzstyle{arrow} = [->,>=stealth]
\begin{tikzpicture}[node distance=1.5cm]
%定义流程图具体形状
\node (start)[startstop]
{开始};
\node (in1) [io, below of = start]
{输入任务包平均价格、聚类中心位置，任务包内会员的指标};
\node (pro1) [process,below of = in1]
{计算任务包的价格、距离、会员能力指标};
\node (pro2) [process, below of = pro1]
{应用多元 logistics 回归分析建立任务包完成度模型};
\node (in2) [io, below of=pro2]
{ 输出每个任务包的完成度 };
\node (stop) [startstop, below of=in2]
{结束};
%连接具体形状
\draw [arrow] (start) -- (in1);
\draw [arrow] (in1) -- (pro1);
\draw [arrow] (pro1) -- (pro2);
\draw [arrow] (pro2) -- (in2);
\draw [arrow] (in2) -- (stop) ;
[->,>=stealth]\end{tikzpicture}
\caption{任务包完成度的建立与求解过程}
\end{figure}
\end{{document}}
