% \begin{table}[h]
%     \centering
%     \caption{Model analysis}
%     \label{tab:model_design}
%     \begin{tabular}{c||c|c||c|c||c|c}
%         \multirow{2}{*}{\textbf{Settings}} & \multicolumn{2}{c}{Citeulike} & \multicolumn{2}{c}{Cellphones} & \multicolumn{2}{c}{Movielen} \\ 
%         - & - & - & - & - & - & -\\
%         - & - & - & - & - & - & -\\
%     \end{tabular}
% \end{table}

\begin{table}[ht]
    \centering
    \caption{Model analysis}
    \label{tab:model_design}
    \begin{tabular}{c||c|c||c|c||c|c}
        \toprule
        \multirow{2}{*}{\textbf{Settings}} & \multicolumn{2}{c||}{Citeulike} & \multicolumn{2}{c||}{Cellphones} & \multicolumn{2}{c}{Movielen} \\ 
        & R@20 & N@20 & R@20 & N@20 & R@20 & N@20\\
        \midrule
        ADDVAE & 0.3167 & 0.2636 & 0.0795 & 0.0561 & 0.2096 & 0.1527\\
        symmetric decoder & 0.3154 & 0.2634 & 0.0821 & 0.0530 & 0.2000 & 0.1464\\
        wo/ $\mathcal{L}^{OT}_u$ & 0.3173 & 0.2641 & 0.0859 & 0.0585 & 0.2096 & 0.1543\\
        default & 0.3185 & 0.2668 & 0.0873 & 0.0589 & 0.2100 & 0.1547\\
        \bottomrule
    \end{tabular}
\end{table}