%%%%%%%%%%%   ALGORITHMS STYLE  %%%%%%%%%%%
% This style defines an environment for algorithms with the following
% features:
% 
% 1) Defines an Theorem like environment (not exactly one) for
%    algorithms called ``algorithm''.
%    \begin{algorithm}{NAME} ... \end{algorithm}
%    NAME is the NAME of the algorithm.
%    Algorithms are numbered using a counter called ``algorithm''. If
%    the style is appropriate (report, book), the numbering takes
%    place within a chapter.
%    The body of the algorithm is italicized.
% 
% 2) Inside this environment, the following commands are defined.
% 
%    \=  Put the small left arrow commonly used for assignment.
% 
%    \invariant{INVARIANT} Use to describe invariants, put its parameter
%                          between ``{}'' in math mode.
% 
%    \begin{Block} ... \end{Block} Environment use to start an indented
%                                  block of instructions.
%    \> and \< are useful equivalents of \begin{Block} and \end{Block}.
% 
% 3) \Blockindent and \algorithmindent are length that specify the
%    indentention of Blocks and of the algorithm resp.
% 
%  4) Instructions are began by ``\\'', ``\instr'', ``\N'' (to have a
%     numbered instruction) or ``\U'' (to have an unnumbered one).
%     Instructions are numbered unless a ``\unnumberalgo'' command is
%     issued. Later a ``\numberedalgo'' switches back to the numbered
%     behavior. Numbered instruction lines can be refered by a \label.
%
%  5) Comments can be done either by the ``\comment{COMMENT}'' or
%     ``\C{COMMENT}'' command. In that case the comment is aligned
%     with the current block, typeset in roman and starts with a specific
%     sign (a triangle obtained by \triangleright).
%
%     Alternatively, one can have end of line comments, aligned to
%     predefined tabulations. The command is
%     ``\tcomment{TAB}{COMMENT}'' or ``\T{TAB}{COMMENT}'', where TAB
%     is a positive number indicating the tab position. 0 indicates
%     the rightmost tab position. To put a comment on tab position 5,
%     one can use \T{5}{A tabulated comment}, or \T5{A tabulated
%     comment}. If TAB > 9, the first version must be used. The
%     formatting is similar to the regular comment. These comments
%     must be put *after* the instruction they refer.
%
%     Comment start sign is defined by the ``\algobegincommentsign''
%     command and comment end sign (empty per default) by the
%     ``\algoendcommentsign'' command. Redefine them to customize to
%     your needs.
% 
%   6) Keywords are typeset in boldface with the predefined commands
%      ``\If'', ``\Then'', ``\Else'', ``\End'', ``\For'', ``\While'',
%      ``\Where'', ``\Elsewhere'', ``\Para'', ``\Case'', ``\Repeat'',
%      ``\Until'' and ``\Do''. 
%
%      If the algorithm is unnumbered, it is closed with a boldface
%      ``end''. It is possible to force algorithm closing by
%      ``\alwaysclosealgo'', to forbidd closing by ``\neverclosealgo''
%      and to switch back to the regular behavior by ``\closeunnumberedalgo''.
%
%   7) By  default, the algorithm is typeset smaller than the text and
%      the comments even smaller. This behavior is useful for
%      articles. For reports, it is better (to my opinion) to have the
%      complete algorithm typeset in normalsize. This behavior is
%      obtained with the ``\largealgo'' command. To switch back to the
%      smaller behavior, use ``\smallalgo''. Any size can be obtained
%      by defining the ``\algocommentsize'' and ``\algoinstrsize''.
%
%   8) To ease the writing of bilingual reports (to us poor Europeans)
%      the commands ``\algorithmname'' (put a the beginning of an
%      algorithm) and ``\endalgorithmname'' (put at the end) can be
%      redefined. The command ``\frenchalgo'' translates them, as well
%      as the predefined keywords in French.
%
% An example file with a simple algorithm is appended at the end of
% this file (after the ``\iffalse'' command).
%
% Created by Alain M\'erigot (am@ief-paris-sud.fr) from an indenting
% environment by Jose Alberto Fernandez R. (alberto@cs.umd.edu).
% 

% 
\def\algobegincommentsign{{$\displaystyle\triangleright$~}}
\def\algoendcommentsign{}
\def\algocommentsize{\footnotesize}
\def\algoinstrsize{\small}
\def\algorithmname{Algorithm}

\def\largealgo{%
\def\algocommentsize{\normalsize}
\def\algoinstrsize{\normalsize}
\setlength{\algorithmindent}{1.5em}
\setlength{\Blockindent}{1.5em}
}
\def\smallalgo{%
\def\algocommentsize{\footnotesize}
\def\algoinstrsize{\small}
\setlength{\algorithmindent}{1.5em}
\setlength{\Blockindent}{1.5em}
}

\def\If{{\bf if\ }}
\def\Then{{\bf then\ }}
\def\Else{{\bf else\ }}
\def\Elsif{{\bf else if\ }}
\def\Begin{{\bf begin\ }}
\def\End{{\bf end\ }}
\def\Cobegin{{\bf cobegin\ }}
\def\Coend{{\bf coend\ }}
\def\For{{\bf for\ }}
\def\Forever{{\bf forever\ }}
\def\To{{\bf to\ }}
\def\Downto{{\bf downto\ }}
\def\While{{\bf while\ }}
\def\Where{{\bf where\ }}
\def\Elsewhere{{\bf elsewhere\ }}
\def\Para{{\bf in parallel\ }}
\def\Case{{\bf case\ }}
\def\Repeat{{\bf repeat\ }}
\def\Wait{{\bf wait\ }}
\def\Until{{\bf until\ }}
\def\Do{{\bf do\ }}
\def\Let{{\bf let\ }}
\def\Read{{\bf read}}
\def\Write{{\bf write}}
\def\Exit{{\bf exit\ }}
\def\Return{{\bf return\ }}
\def\Goto{{\bf goto\ }}
\def\Mod{{\bf mod\ }}
%\def\true{\textrm{true}}
%\def\false{\textrm{false}}
\def\endalgorithmname{end}

\def\frenchalgo{\def\algorithmname{Algorithme}
\def\If{{\bf si\ }}
\def\Then{{\bf alors\ }}
\def\Else{{\bf sinon\ }}
\def\End{{\bf fin\ }}
\def\For{{\bf pour\ }}
\def\To{{\bf \`a\ }}
\def\Downto{{\bf \`a\ }}
\def\While{{\bf tant que\ }}
\def\Where{{\bf partout o\`u\ }}
\def\Elsewhere{{\bf ailleurs\ }}
\def\Para{{\bf en parall\`ele\ }}
\def\Case{{\bf selon\ }}
\def\Repeat{{\bf r\'ep\'eter\ }}
\def\Until{{\bf jusqu'\`a ce que\ }}
\def\Do{{\bf faire\ }}
\def\Let{{\bf soit\ }}
\def\endalgorithmname{fin}
}

\newif\if@nalgo \@nalgotrue % vrai si on numerote les algorithmes
\def\numberedalgo{\@nalgotrue}
\def\unnumberedalgo{\@nalgofalse}
\newif\if@alwaysclosealgo \@alwaysclosealgofalse
\newif\if@neverclosealgo \@neverclosealgofalse
\def\alwaysclosealgo{\@alwaysclosealgotrue}
\def\neverclosealgo{\@neverclosealgotrue}
\def\closeunnumberedalgo{\@alwaysclosealgofalse\@neverclosealgofalse}


\@ifundefined{chapter}{\newcounter{algorithm}}%
{\newcounter{algorithm}[chapter]\def\thealgorithm{\thechapter.\arabic{algorithm}}}
\newcounter{algorithmline}
\newlength{\linelabelwidth}
\newlength{\margindistance}
\setlength{\linelabelwidth}{1em}
\newlength{\commenttab}
%\setlength\commenttab{5em}
\setlength\commenttab{0.06\columnwidth}

%\newtheorem{Alg@orithm}[algorithm]{\algorithmname}
%\newenvironment{Alg@orithm}[1]{\smallskip\par\refstepcounter{algorithm}
%\noindent{\algoheaderstyle\algorithmname~\thealgorithm}~{\algotitlestyle
%{#1}}\algobodystyle}{}
\newenvironment{Alg@orithm}[1]{\algotitlestyle
{#1}\algobodystyle}{}


% Invariants
\newcommand{\inv@ariant}[1]{\mbox{$\{#1\}$}}
% Steps environment
\newenvironment{ste@ps}[2]{
% #1 l'indentation des item, #2 la distance absolue item -- marge
\begin{list}{}
{\setlength\labelsep{#2}
\setlength\labelwidth{\linelabelwidth}
\setlength\partopsep{0pt}
\setlength\parsep{0in}
\setlength\parskip{0pt}
\setlength\topsep{0in}
\setlength\itemsep{0in}
\setlength\itemindent{0in}
\setlength\listparindent{0in}
\setlength\parindent{0pt}
\setlength\rightmargin{0in}
\setlength\leftmargin{#1}%
}
}{
\end{list}
}

% Block environment
% Indentation of the Block
\newlength{\Blockindent}


\newenvironment{Blo@ck}{
\addtolength{\margindistance}{\Blockindent}
\begin{ste@ps}{\Blockindent}{\margindistance}
}{
\addtolength{\margindistance}{-1.0\Blockindent}
\end{ste@ps}
%end
}
\newsavebox{\algosbox}
\newlength{\algosboxwidth}
\newlength{\algototab}
\def\ind@ent{\begin{Block}}
\def\deind@ent{\end{Block}}




\def\emalgo{\def\algonumberstyle{\em}\def\algocommentstyle{\em}\def\algoheaderstyle{\bf}\def\algotitlestyle{\it}\def\algobodystyle{\it}}
\def\rmalgo{\def\algonumberstyle{\rm}\def\algocommentstyle{\rm}\def\algoheaderstyle{\bf}\def\algotitlestyle{\rm}\def\algobodystyle{\rm}}


\def\instr@{\refstepcounter{algorithmline}\item[{\algonumberstyle\thealgorithmline}\hfill]%
}
\def\uinstr@{\item[]}

\def\comm@ent#1{\item\algobegincommentsign{\algocommentsize\algocommentstyle
#1}\algoendcommentsign}
\def\tcomm@ent#1#2{%
\vspace{-1.0\baselineskip}% on remonte
\par%on va a la ligne
% on commence par calculer la distance a la tabulation
% la distance sera de la tabulation i sera finligne - 4em -i*tabstop
% avec tabstop d'environ texwidth/15
\setlength{\algototab}{\columnwidth}\addtolength{\algototab}{-4.0em}%
\addtolength{\algototab}{-#1\commenttab}%
\hspace{-1.0\margindistance}\hspace{\algototab}% on est a la tabulation
\savebox{\algosbox}{\algobegincommentsign{\algocommentsize\algocommentstyle
#2}\algoendcommentsign}%
\usebox{\algosbox}%
\settowidth{\algosboxwidth}{\usebox{\algosbox}}\hspace{-1.0\algosboxwidth}%
% on est revenu a la tabulation
\hspace{-1.0\algototab}% et on revient a la marge
% et on peut faire un \item normal
}

% Algorithm environment
% Assign command
\newcommand{\ass@ign}{\mbox{$\leftarrow$}}
% Indentation of the algorithm
\newlength{\algorithmindent}
% Algorithm definition
\newenvironment{algorithm}[1]{
\begin{Alg@orithm}{#1}
\let\>\ind@ent
\let\<\deind@ent
\let\=\ass@ign
\if@nalgo \let\\\instr@ \let\instr\instr@
\else\let\\\uinstr@ \let\instr\uinstr@\fi
\let\U\uinstr@
\let\N\instr@
\let\comment\comm@ent
\let\C\comm@ent
\let\tcomment\tcomm@ent
\let\T\tcomm@ent
\let\invariant\inv@ariant
\let\Block\Blo@ck
\let\endBlock\endBlo@ck
\setlength{\margindistance}{\algorithmindent}
\addtolength\margindistance{-1.0\linelabelwidth}
\setcounter{algorithmline}{0}
\algoinstrsize\par
\nopagebreak[4]
\begin{ste@ps}{\algorithmindent}{\margindistance}
}{
\end{ste@ps}
\if@nalgo\if@alwaysclosealgo\nopagebreak[4]\bf\endalgorithmname\fi%
\else\if@neverclosealgo\else\nopagebreak[4]\bf\endalgorithmname\fi\fi
\end{Alg@orithm}
}

% Setting default style
\smallalgo\rmalgo 
% End of algorithm.sty