Reduce the size of horizontal line

Question

I want to reduce the size of horizontal line.

\begin{frame}
\restylealgo{boxed}
\begin{algorithm}[H]
\Setline
\nl i\;
\end{algorithm}
\end{frame}

Answer 1

Place the contents of your algorithm inside a minipage of the appropriate width. Here's an example highlighting this:

\documentclass{beamer}% http://ctan.org/pkg/beamer
\usepackage{algorithm2e}% http://ctan.org/pkg/algorithm2e
\begin{document}
\begin{frame}
  \RestyleAlgo{boxed}
  \begin{algorithm}[H]
    \SetAlgoLined
    \nl i\;
  \end{algorithm}

  \bigskip

  \begin{minipage}{.5\linewidth}
  \begin{algorithm}[H]
    \SetAlgoLined
    \nl i\;
  \end{algorithm}
  \end{minipage}
\end{frame}
\end{document}

Also, you should update your version of algorithm2e. Since version 4.0, some commands have been modified - I'm using them above.