% \begin{figure}[t]
%     \begin{subfigure}[t]{\columnwidth}
%         \centering
%         \input{figures/fusion_method/citeulike}
%         % \vspace*{-5mm}
%         \caption{Results on CiteULike-a}
%     \end{subfigure}
%     \\
%     \begin{subfigure}[t]{\columnwidth}
%         \centering
%         \input{figures/fusion_method/cellphones}
%         % \vspace*{-5mm}
%         \caption{Results on Cell Phones}
%     \end{subfigure}
%     \\
%     \begin{subfigure}[t]{\columnwidth}
%         \centering
%         \input{figures/fusion_method/movielens}
%         % \vspace*{-5mm}
%         \caption{Results on MovieLens}
%     \end{subfigure}
%     \\
%     \begin{subfigure}[t]{\columnwidth}
%         \centering
%         \input{figures/fusion_method/videogames}
%         % \vspace*{-5mm}
%         \caption{Results on Video Games}
%     \end{subfigure}%
%     \caption{The left figure in each row compares two fusion methods, \emph{Mean-T} and \emph{Adaptive}, which are described in Section ~\ref{sec:model_analysis}. The right figure reports accuracy when $\mathcal{L}^t_u$ is excluded and involved in \ourmethod, respectively. \textcolor{blue!60!white}{Blue bars} represent Recall@10 while \textcolor{red!60!white}{red bars} show NDCG@10.}
%     \label{fig:fusion_lambda_text}
% \end{figure}

\begin{figure}[!ht]
    \begin{subfigure}[t]{0.5\columnwidth}
        \centering
        \includegraphics[scale=0.23]{figures/fusion_method/reg_citeulike.pdf}
    \end{subfigure}%
    \begin{subfigure}[t]{0.5\columnwidth}
        \centering
        \includegraphics[scale=0.23]{figures/fusion_method/reg_cellphones.pdf}
    \end{subfigure}
    \\
    \begin{subfigure}[t]{0.5\columnwidth}
        \centering
        \includegraphics[scale=0.23]{figures/fusion_method/reg_videogames.pdf}
    \end{subfigure}%
    \begin{subfigure}[t]{0.5\columnwidth}
        \centering
        \includegraphics[scale=0.23]{figures/fusion_method/reg_movielens.pdf}
    \end{subfigure}
    \caption{Fusion method comparison \emph{Mean-T} vs. \emph{Adaptive}.}
    \label{fig:fusion_lambda_text}
\end{figure}

% \begin{figure}[t]
%     \begin{subfigure}[t]{\columnwidth}
%         \centering
%         \input{figures/fusion_method/citeulike}
%         % \vspace*{-5mm}
%         \caption{Results on CiteULike-a}
%     \end{subfigure}
%     \\
%     \begin{subfigure}[t]{\columnwidth}
%         \centering
%         \input{figures/fusion_method/cellphones}
%         % \vspace*{-5mm}
%         \caption{Results on Cell Phones}
%     \end{subfigure}
%     \\
%     \begin{subfigure}[t]{\columnwidth}
%         \centering
%         \input{figures/fusion_method/movielens}
%         % \vspace*{-5mm}
%         \caption{Results on MovieLens}
%     \end{subfigure}
%     \\
%     \begin{subfigure}[t]{\columnwidth}
%         \centering
%         \input{figures/fusion_method/videogames}
%         % \vspace*{-5mm}
%         \caption{Results on Video Games}
%     \end{subfigure}%
%     \caption{The left figure in each row compares two fusion methods, \emph{Mean-T} and \emph{Adaptive}, which are described in Section ~\ref{sec:model_analysis}. The right figure reports accuracy when $\mathcal{L}^t_u$ is excluded and involved in \ourmethod, respectively. \textcolor{blue!60!white}{Blue bars} represent Recall@10 while \textcolor{red!60!white}{red bars} show NDCG@10.}
%     \label{fig:fusion_lambda_text}
% \end{figure}