\begin{table*}[t]
    \centering\small
    \setlength{\tabcolsep}{2pt}
    \begin{tabular}{l ccc ccc ccc}
        \toprule
		
        & \multicolumn{3}{c}{MMD $\downarrow$}             
        & \multicolumn{3}{c}{Coverage$\uparrow$}
        & \multicolumn{3}{c}{Density}\\
        
	\cmidrule(lr){2-4}
        \cmidrule(lr){5-7}
        \cmidrule(lr){8-10}
  
	& \multicolumn{1}{c}{CD} & EMD & $L^2$
        & CD & EMD & $L^2$
        & CD & EMD & $L^2$\\
  
	\midrule
  
	\citet{luo2021diffusion}    
        & 4.06 & 1.78 & 15.07
        & 0.0027 & 0.0064 & 5.4 $\times10^{-4}$
        & 4.6$\times10^{-4}$ & 0.0038 & 7.72 $\times10^{-5}$ \\

        \citet{zeng2022lion}    
        & \textbf{2.42} & 1.34 & 14.26
        & 0.17 & 0.078 & 0.0016
        & 0.097 & 0.048 & 0.0045\\
            
        PCA  
        & 2.94 & 1.36 & 1.37
        & 0.16 & 0.12 & 0.12
        & 1.54 & 1.75 & 1.73\\
  
	\midrule
  
	Ours 
        & 2.52 & \textbf{1.19} & \textbf{1.19}   
        & \textbf{0.36} & \textbf{0.22} & \textbf{0.22}
        & 0.37 & 0.19 & 0.19\\

        \midrule

        Ablation
        & \textcolor{gray}{35.11} & \textcolor{gray}{6.18} & \textcolor{gray}{7.95}
        & \textcolor{gray}{0.003} & \textcolor{gray}{0.003} & \textcolor{gray}{0.003}
        & \textcolor{gray}{0.04} & \textcolor{gray}{0.05} & \textcolor{gray}{0.03}\\

        Real data 
        & \textcolor{gray}{1.42} & \textcolor{gray}{0.81} & \textcolor{gray}{0.82}
        & \textcolor{gray}{0.98} & \textcolor{gray}{0.99} & \textcolor{gray}{0.99}
        & \textcolor{gray}{0.96} & \textcolor{gray}{0.97} & \textcolor{gray}{0.97}\\
        
	\bottomrule
	\end{tabular}
	\caption{Quantitative comparison for point cloud generation. MMD: lower the better, coverage: higher the better, density: the closer to 1 the better.  CD, EMD and $L$2 distances are used as the distance measure.}
	\label{tab:metrics}
\end{table*}
