% \begin{figure}[!ht]
%     \begin{subfigure}{\columnwidth}
%         \centering
%         \input{figures/epsilon/citeulike}
%         % \vspace*{-5mm}
%         \caption{Results on CiteULike-a}
%     \end{subfigure}
%     \\
%     \begin{subfigure}{\columnwidth}
%         \centering
%         \input{figures/epsilon/cellphones}
%         % \vspace*{-5mm}
%         \caption{Results on Cell Phones}
%     \end{subfigure}
%     % \\
%     % \begin{subfigure}{\columnwidth}
%     %     \centering
%     %     \input{figures/epsilon/movielens}
%     %     % \vspace*{-5mm}
%     %     \caption{Results on MovieLens}
%     % \end{subfigure}%
%     \\
%     \begin{subfigure}{\columnwidth}
%         \centering
%         \input{figures/epsilon/videogames}
%         % \vspace*{-5mm}
%         \caption{Results on Video Games}
%     \end{subfigure}%
%     \\
%     \begin{subfigure}{\columnwidth}
%         \centering
%         \input{figures/epsilon/movielens}
%         % \vspace*{-5mm}
%         \caption{Results on MovieLens}
%     \end{subfigure}%
%     \caption{\ourmethod's performance w.r.t. $\epsilon$ in Equation ~\ref{eqn:regularized_OT}.}
%     \label{fig:epsilon}
% \end{figure}

\begin{figure*}[!ht]
    \begin{subfigure}{0.25\textwidth}
        \centering
        \input{figures/epsilon/citeulike}
        \caption{Results on CiteULike-a}
    \end{subfigure}%
    \begin{subfigure}{0.25\textwidth}
        \centering
        \input{figures/epsilon/cellphones}
        \caption{Results on Cell Phones}
    \end{subfigure}%
    \begin{subfigure}{0.25\textwidth}
        \centering
        \input{figures/epsilon/videogames}
        \caption{Results on Video Games}
    \end{subfigure}%
    \begin{subfigure}{0.25\textwidth}
        \centering
        \input{figures/epsilon/movielens}
        \caption{Results on MovieLens}
    \end{subfigure}
    \caption{\ourmethod's performance w.r.t. $\epsilon$ in Equation ~\ref{eqn:regularized_OT}.}
    \label{fig:epsilon}
\end{figure*}