% \begin{wraptable}{r}{6cm}
%     \caption{Efficiency comparison between \ourmethod\, ADDVAE and VALID, in terms of running time (seconds per training epoch) and memory required for training (measured in GB).}
%     \label{tab:running_time}
%     \small
%     \scalebox{0.86}{
%     \begin{tabular}{c@{\hskip 0.08in}c@{\hskip 0.06in}c@{\hskip 0.06in}c@{\hskip 0.06in}}
%         \toprule
%         \textbf{Model} & \textbf{Citeulike-a} & \textbf{Cell Phones} & \textbf{MovieLens}\\
%         \midrule
%         \ourmethod & 1.7525 & 6.1622 & 3.1120 \\
%         ADDVAE & 1.6856 & 5.6608 & 2.9653 \\
%          \bottomrule
%     \end{tabular}
%     }
% \end{wraptable}

\begin{table}
    \caption{Efficiency comparison between \ourmethod, ADDVAE and VALID w.r.t. running time (seconds per training epoch) and memory required for training (measured in GB).}
    \label{tab:running_time}
    \centering
    % \small
    \scalebox{0.86}{
    \begin{tabular}{c
                    c@{\hskip 0.03in}c
                    c@{\hskip 0.03in}c
                    c@{\hskip 0.03in}c
                    c@{\hskip 0.03in}c}
        \toprule
        \multirow{3}{*}{\textbf{Model}} & \multicolumn{2}{c}{\textbf{CiteULike-a}} & \multicolumn{2}{c}{\textbf{MovieLens}} & \multicolumn{2}{c}{\textbf{Cell Phones}} & \multicolumn{2}{c}{\textbf{Video Games}}\\
        \cmidrule(lr){2-3}\cmidrule(lr){4-5}\cmidrule(lr){6-7}\cmidrule(lr){8-9}
        & \makecell{Time\\(s)} & \makecell{Mem\\(GB)} & \makecell{Time\\(s)} & \makecell{Mem\\(GB)}& \makecell{Time\\(s)} & \makecell{Mem\\(GB)} & \makecell{Time\\(s)} & \makecell{Mem\\(GB)}\\
        \midrule
        ADDVAE & 1.82 & 2.48 & 3.26 & 1.92 & 6.08 & 2.38 & 10.82 & 2.44\\
        VALID & 1.51 & 2.96 & 2.09 & 1.99 & 6.20 & 4.58 & 9.33 & 2.89\\
        \ourmethod & 1.95 & 3.39 & 3.68 & 2.52 & 8.38 & 4.89 & 14.68 & 3.38\\
         \bottomrule
    \end{tabular}
    }
\end{table}