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+% \iffalse
+% File: lcg.dtx
+%% Copyright (C) 2001 Erich Janka (janka@utanet.at)
+%%
+%% This package may be distributed  and/or modified under the terms of the
+%% LaTeX Project Public License, as described in lppl.txt in the base
+%% LaTeX distribution, either version 1.2 or (at your option)
+%% any later version.
+%% The latest version of this license is in
+%%    http://www.latex-project.org/lppl.txt
+%%
+%% This program consits of the files lcg.dtx and lcg.ins
+%
+%<lcg>\NeedsTeXFormat{LaTeX2e}
+%<lcg>\ProvidesPackage{lcg}[2001/03/03 v1.0 generating random numbers]
+%<lcg>\RequirePackage{keyval}
+%
+%<*driver>
+\documentclass{ltxdoc}
+\usepackage[first=10, last=20]{lcg}
+\begin{document}
+  \GetFileInfo{lcg.sty}
+  \title{The \texttt{lcg} package}
+  \author{Erich Janka\\ \texttt{janka@utanet.at}}
+  \date{2001/03/03 (v1.0)}
+  \maketitle
+  \DocInput{lcg.dtx}
+\end{document}
+%
+%</driver>
+% \fi
+%
+% \iffalse
+%<*lcg>
+% \fi
+%
+% \newcommand{\mod}{\;\;\mbox{mod}\;\;}
+% \newcommand{\key}[1]{\meta{#1}}
+% \newcommand{\cntr}[1]{\texttt{#1}}
+%
+% \begin{abstract}
+%
+% This Package contains macros to generate (pseudo) random numbers
+% with \LaTeX\ by a simple linear congruential generator.
+% The user can specify a range of integers
+% containing the generated random numbers.
+%
+% To pass options to the package, the \meta{key}=\meta{value}
+% scheme of the \texttt{keyval} package is used.
+%
+% If no options are specified, random numbers will be
+% generated in the interval from $1$ to $2^{31}-1 \;\;(= 2147483647)$.
+% Let $S$ be the smallest and $L$ the largest number of the specified range,
+% then the following inequalities must hold  because of
+% limitations of \LaTeX:
+%
+% $$  -2^{31}+1 \leq S \leq L \leq  2^{31}-1   \qquad\mbox{and}\qquad
+%     L-S \leq  2^{31}-2 $$
+%
+% The generated random numbers will be stored in a \LaTeX\
+% counter definable by the user.
+% \end{abstract}
+%
+% \section{User Interface}
+%
+% The \texttt{lcg} package is loaded with\\[1ex]
+% \hspace*{2ex}\cmd{\usepackage\oarg{list of options}\{lcg\}}.\\[1ex]
+% The optional Argument is a comma separated list of entries of
+% the kind \key{key}=\key{value} or \key{key}. In the second case
+% the key will be set to a standard value.
+% For example the line\\[1ex]
+% \hspace*{2ex}\cmd{\usepackage[first=10, last=20]\{lcg\}}\\[1ex]
+% loads the package and generates the \LaTeX\ counter \cntr{rand}
+% which will hold pseudo random numbers from $10$ to $20$.
+% All available keys and their standard values are introduced below.
+% \begin{macro}{\rand}
+% Each call of the command \cmd{\rand} will write a new random number
+% to the counter provided by the user with the key \key{counter} or
+% to the standard counter of this package---\cntr{rand}. Now
+% it's possible to do whatever can be done with counters. The command
+% evokes a linear congruential random number generator described below.
+% \end{macro}
+% \begin{macro}{\reinitrand}
+% The command \cmd{\reinitrand}\oarg{list of options} has
+% one optional argument which is identical to the argument of
+% \cmd{\usepackage},
+% i.~e. the same keys in the comma separated list are allowed.
+% The effect is that specified keys will be set and all others
+% will be reset to their standard values.
+% \end{macro}
+% \begin{macro}{\chgrand}
+% The syntax of the command \cmd{\chgrand} is identical to \cmd{\reinitrand}.
+% The difference is that \cmd{\chgrand} will set the specified keys but
+% won't effect any other key.
+% \end{macro}
+%
+% \subsection{The Options}
+%
+% This section deals with the list of all available keys
+% and their standard values.
+% \begin{macro}{counter}
+% This key sets the name of the \LaTeX\ counter where
+% the random numbers will be stored.
+% If the counter already exists (maybe somebody likes
+% random page numbers), \LaTeX\ will prompt a
+% warning and will use it. If the counter doesn't exist,
+% it will be defined by this package and set to $0$.\\
+% \textbf{Standard value:} rand
+% \end{macro}
+% \begin{macro}{first}
+% This key sets the left boarder of the range within
+% random numbers will be generated.
+% Its value can be any number from $-2^{31}+1$ to $2^{31}-1$,
+% as long as it is not greater than the value of the key \key{last}
+% and the difference to the value of \key{last} doesn't exceed
+% $2^{31}-2$.\\
+% \textbf{Standard value:} $1$
+% \end{macro}
+% \begin{macro}{last}
+% This key sets the right boarder of the range within
+% random numbers will be generated. Its value can be any
+% number from $-2^{31}+1$ to $2^{31}-1$,
+% as long as it is not less than the value of the key \key{first}
+% and the difference to the value of \key{first} doesn't exceed
+% $2^{31}-2$.\\
+% \textbf{Standard value:} $2^{31}-1$
+% \end{macro}
+% \begin{macro}{seed}
+% The value of this key is the starting value
+% for the algorithm generating the random numbers
+% and must be within the range $1$ to $2^{31}-1$.
+% If the value is smaller than $1$,
+% the random number generator will
+% be initialized with the time, the page number and
+% the actual line of the file. This key allows
+% reproduction of the sequences of random numbers.\\
+% \textbf{Standard value:} $0$
+% \end{macro}
+% \begin{macro}{quiet}
+% When using the \texttt{lcg} package it sends some lines of
+% information to the screen and the \texttt{log}-file:
+% \begin{itemize}
+%   \setlength{\itemsep}{-3pt}
+%   \item[--] The name of the counter holding the generated random numbers
+%   \item[--] The lower bound of the range of random numbers
+%   \item[--] The upper bound of the range of random numbers
+%   \item[--] The initial value of the random number generator
+% \end{itemize}
+% To supress this output this key
+% can be used. If the value starts with the letter \emph{y}, \emph{Y},
+% \emph{j} or \emph{J}
+% there will be no output whereas words beginning
+% with the letters \emph{n} or \emph{N} won't supress it.\\
+% \textbf{Standard value:} $y$
+% \end{macro}
+%
+% \section{Example}
+%
+% This documentation loaded the package with:
+% \begin{verbatim}
+%   \usepackage[first=10, last=20]{lcg}\end{verbatim}
+% The lines
+% \begin{verbatim}
+%   \rand\arabic{rand} \rand\arabic{rand} \rand\arabic{rand}
+%   \rand\arabic{rand} \rand\arabic{rand} \rand\arabic{rand}
+%   \rand\arabic{rand} \rand\arabic{rand} \rand\arabic{rand}\end{verbatim}
+% generate these numbers (all between 10 and 20):
+% \rand\arabic{rand} \rand\arabic{rand} \rand\arabic{rand}
+% \rand\arabic{rand} \rand\arabic{rand} \rand\arabic{rand}
+% \rand\arabic{rand} \rand\arabic{rand} \rand\arabic{rand}
+%
+% Now the counter \cntr{die} should simulate a die and hold
+% random numbers from $1$ to $6$. In addition it is demonstrated
+% how to switch off the output to the screen and to the \texttt{log}-file.
+% This can achieved with one of the following lines:
+% \begin{verbatim}
+%   \reinitrand[last=6, counter=die, quiet]\end{verbatim}
+% \reinitrand[last=6, counter=die]
+% After that, the numbers
+% \rand\arabic{die} \rand\arabic{die} \rand\arabic{die}
+% \rand\arabic{die} \rand\arabic{die} \rand\arabic{die}.
+% are a product of:
+% \begin{verbatim}
+%   \rand\arabic{die} \rand\arabic{die} \rand\arabic{die}
+%   \rand\arabic{die} \rand\arabic{die} \rand\arabic{die}\end{verbatim}
+% As one can see, the key \meta{first} has been reset to $1$. 
+%
+% The following lines  will change the range to $-6$ to $+6$
+% without modifying any other option:
+% \begin{verbatim}   \chgrand[first=-6]\end{verbatim} \chgrand[first=-6]
+% Here the numbers
+% \rand\arabic{die} \rand\arabic{die} \rand\arabic{die}
+% \rand\arabic{die} \rand\arabic{die} \rand\arabic{die}
+% are stored in a user defined counter and brought to paper
+% by:
+% \begin{verbatim}
+%   \rand\arabic{die} \rand\arabic{die} \rand{arabic}{die}
+%   \rand\arabic{die} \rand\arabic{die} \rand\arabic{die}\end{verbatim}
+%
+% At last, random numbers between $1$ and $12$ will
+% be generated and stored in the standard counter \cntr{rand}.
+% The seed will be set to $1234$. There will also be a warning because
+% the name of the counter is set to \texttt{rand} which was already
+% defined when calling the package:
+% \begin{verbatim}   \reinitrand[last=12, seed=1234]\end{verbatim}
+% \reinitrand[last=12, seed=1234]
+% \begin{verbatim}
+%   \rand\Roman{rand} \rand\Roman{rand} \rand\Roman{rand} \end{verbatim}
+% These lines produce:  \rand\Roman{rand} \rand\Roman{rand} \rand\Roman{rand}.
+% When using other formats than \texttt{arabic} for printing,
+% the desired numbers might not appear on the screen
+% because these formats don't support the full range of $2^{31}-1$.
+%
+%
+% \section{The Linear Congruential Generator}
+%
+% The linear congruential generator used produces
+% a sequence of numbers $I_j$ in the range from
+% $1$ to $m$ by following rule:
+% $$ I_{j+1} =   a I_j \mod m  $$
+% where $I_0$ is set to a arbitrary starting value (called ``seed'').
+% The quality of this generator depends on the choice of the
+% parameters $a$ and $m$.
+% Another problem is that when implementing the algorithm as above,
+% the multiplication might leave the range \LaTeX\ can deal with.
+% The solution is Schrage's method [\textsc{W.~Press} et~al.
+% \emph{Numerical Recipies in \texttt{C}}\@.
+% 2nd edition. Cambridge University Press 1992] which allows
+% to perform the multiplications without leaving the given range.
+% This is done by introducing two variables $r$ and $q$:
+%  $$
+%    m = a q + r  \qquad\mbox{with}\qquad
+%    q = \left[m/a\right]\quad\mbox{and}\quad r = m \mod a
+%  $$
+% where $[\,\cdot\,]$ denotes the integer part of the argument.
+% If $z$ is an integer and $0 \leq r < q$ and $0 < z < m-1$,
+% then the following (in)equalities hold:
+% \begin{eqnarray*}
+%  &  0 \leq a \cdot (z \mod q) \leq m-1\\
+%  &  0 \leq \left[m/a\right] \leq m-1\\
+%  &  a z \mod m = \left\{
+%       \begin{array}{ll} a \cdot (z \mod q ) -
+%           \left[z/q\right] & \mbox{if the term is } \leq 0\\
+%               a \cdot (z \mod q ) -
+%           \left[z/q\right] + m & \mbox{otherwise}
+%       \end{array}\right.
+% \end{eqnarray*}
+%
+% To exploit the whole possible range and guarantee good performance,
+% $a$ and $m$ are set as follows:
+% $a = 7^5  \; = 16807$ and $m  = 2^{31}-1 \; = 2147483647$ and
+% this gives $q=127773$ and $r=2836$.
+%
+%
+% \section{The Code}
+%
+% \subsection{Checking for possible conflicts}
+%
+% The following lines check if the commands provided by
+% this package are already defined:
+%
+%    \begin{macrocode}
+\@ifundefined{rand}{}
+       {\PackageWarning{lcg}{Command `rand' already defined}}
+\@ifundefined{r@ndcountername}{}
+       {\PackageWarning{lcg}{Command `r@ndcountername'
+         already defined}}
+%    \end{macrocode}
+% Checking internal commands:
+%    \begin{macrocode}
+\@ifundefined{r@nd}{}
+       {\PackageWarning{lcg}{Command `r@nd' already defined}}
+\@ifundefined{initr@nd}{}
+       {\PackageWarning{lcg}{Command `initr@nd' already defined}}
+\@ifundefined{cutr@nger@nd}{}
+       {\PackageWarning{lcg}{Command `cutr@nger@nd' already defined}}
+\@ifundefined{@rderr@nd}{}
+       {\PackageWarning{lcg}{Command `@rderr@nd' already defined}}
+\@ifundefined{ProcessOptionsWithKVr@nd}{}
+       {\PackageWarning{lcg}{Command `ProcessOptionsWithKVr@nd'
+         already defined}}%
+\@ifundefined{qui@t}{}
+       {\PackageWarning{lcg}{Command `qui@t' already defined}}
+\@ifundefined{firstletterr@nd}{}
+       {\PackageWarning{lcg}{Command `firstletterr@nd' already defined}}
+       %    \end{macrocode}
+% Checking the used counters:
+%    \begin{macrocode}
+\@ifundefined{c@f@rst}{}
+       {\PackageWarning{lcg}{Counter `f@rst' already defined}}
+\@ifundefined{c@l@st}{}
+       {\PackageWarning{lcg}{Counter `l@st' already defined}}
+\@ifundefined{c@cr@nd}{}
+       {\PackageWarning{lcg}{Counter `cr@nd' already defined}}
+\@ifundefined{f@rst}{}
+       {\PackageWarning{lcg}{Existing command `f@rst' conflicts
+         with counter `f@rst'}}
+\@ifundefined{l@st}{}
+       {\PackageWarning{lcg}{Existing command `l@st' conflicts
+         with counter `l@st'}}
+\@ifundefined{cr@nd}{}
+       {\PackageWarning{lcg}{Existing command `cr@nd' conflicts
+         with counter `cr@nd'}}
+%    \end{macrocode}
+%
+%
+% \subsection{Macros for (re)initialization}
+%
+% \begin{macro}{init}
+%  Set starting values for the parameters and counters
+%  to standard values or according to the provides keys
+%    \begin{macrocode}
+\def\initr@nd{%
+   \def\r@ndcountername{rand}%
+   \newcount \f@rst
+   \newcount \l@st
+   \newcount \cr@nd
+   \pr@keysr@nd%
+   \ProcessOptionsWithKVr@nd{Init}%
+   \p@stkeysr@nd%
+   \@utputr@nd%
+}  % end of \def\initr@nd
+%    \end{macrocode}
+% \end{macro}
+% \begin{macro}{reinit}
+%  Sets the provided keys and resets all other options.
+%    \begin{macrocode}
+\def\reinitrand{\@ifnextchar[\@reinitr@nd{\@reinitr@nd[]}}%
+\def\@reinitr@nd[#1]{%
+    \pr@keysr@nd%
+    \setkeys{Init}{#1}%
+    \p@stkeysr@nd%
+    \@utputr@nd%
+}%    end of \def\reinitrand
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{chgrand}
+%  Sets the provided keys and doesn't change any other option.
+%    \begin{macrocode}
+\def\chgrand{\@ifnextchar[\@chgr@nd{\@chgr@nd[]}}
+\def\@chgr@nd[#1]{%
+    \@tempcnta = \z@
+    \@tempcntb = \z@
+    \setkeys{Init}{#1}%
+    \p@stkeysr@nd%
+    \@utputr@nd%
+}  % end of \def\chgrand
+%    \end{macrocode}
+% \end{macro}
+%
+%
+% \subsection{The keys}
+%
+% \begin{macro}{use keys}
+% The following lines are from the \texttt{geometry} package
+% written by \textsc{Hideo Umeki} (who borrowed it from the
+% \texttt{hyperref}  package written by \textsc{Sebastian Rahtz}).
+% It enables the usage of the \meta{key}=\meta{value} scheme of the
+% keyval package.
+%
+%    \begin{macrocode}
+\def\ProcessOptionsWithKVr@nd#1{%
+  \let\@tempa\@empty
+  \@for\CurrentOption:=\@classoptionslist\do{%
+    \@ifundefined{KV@#1@\CurrentOption}%
+    {}{\edef\@tempa{\@tempa,\CurrentOption,}}}
+  \edef\@tempa{%
+    \noexpand\setkeys{#1}{\@tempa\@ptionlist{\@currname.\@currext}}}
+  \@tempa
+  \AtEndOfPackage{\let\@unprocessedoptions\relax}}
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{first}
+%    \begin{macrocode}
+\define@key{Init}{first}[1]{\f@rst = #1}
+%    \end{macrocode}
+% \end{macro}
+% \begin{macro}{last}
+%    \begin{macrocode}
+\define@key{Init}{last}[2147483647]{\l@st = #1}
+%    \end{macrocode}
+% \end{macro}
+% \begin{macro}{counter}
+%    \begin{macrocode}
+\define@key{Init}{counter}[rand]{\def\r@ndcountername{#1}}
+%    \end{macrocode}
+% \end{macro}
+% \begin{macro}{seed}
+%    \begin{macrocode}
+\define@key{Init}{seed}[\z@]{% seed for random number generator
+   \ifnum #1 < \z@%
+      \PackageWarning{lcg}{Seed should be > 0 --
+              Seed will be initialized with the actual time}%
+      \cr@nd = \z@%
+   \else%
+      \cr@nd = #1
+      \typeout{Random number generator initialized to #1}%
+   \fi%
+}
+%    \end{macrocode}
+% \end{macro}
+% \begin{macro}{quiet}
+%    \begin{macrocode}
+\define@key{Init}{quiet}[y]{
+   \def\qui@t{\expandafter\firstletterr@nd #1\delimiter}
+   \if\qui@t y    % nothing to do
+   \else\if\qui@t Y \def\qui@t{y}
+   \else\if\qui@t j \def\qui@t{y}
+   \else\if\qui@t J \def\qui@t{y}
+   \else\if\qui@t n \def\qui@t{n}
+   \else\if\qui@t N \def\qui@t{n}
+   \else 
+      \PackageWarning{lcg}{Value of key <quiet> must be <y> or <n>}
+      \def\qui@t{y}
+   \fi\fi\fi\fi\fi\fi
+}
+%    \end{macrocode}
+% \end{macro}
+%
+% \subsection{Macros called by other macros}
+%
+% \begin{macro}{pr@keys}
+% The command \cmd{\pr@keysr@nd} is used to define and initialize
+% all parameters (counters) needed by this package (before
+% the keys are evaluated).
+% Random numbers will be generated from $\mathtt{f@rst}$ to
+% $\mathtt{f@rst} + \mathtt{l@st} - 1$,
+% \cntr{cr@nd} will hold the random numbers
+% (full range: $1$ to $2^{31}-1$) and \cntr{rand}
+% will hold the random numbers (user defined range).
+% The counters are also initialized to standard values.
+% If the counter \cntr{cr@nd} equals zero, the seed will be
+% initialized according to the actual time by the command \cmd{\r@nd}:
+%
+%    \begin{macrocode}
+\def\pr@keysr@nd{%
+    \f@rst = \@ne        % 1
+    \l@st = 2147483647   % 2147483647
+    \cr@nd  = \z@        % 0
+    \@tempcnta = \z@
+    \@tempcntb = \z@
+    \def\r@ndcountername{rand}%
+    \def\qui@t{n}
+} % end of newcommand\def\pr@keysr@nd
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{p@stkeys}
+% The command \cmd{\p@stkeysr@nd} is executed after the
+% keys are evaluated as last step of the initialization.
+% The setting of the counter \cntr{l@st} depends on weather
+% the key \key{last} is set or not.
+% and the counter (user defined or standard name) is created.
+%    \begin{macrocode}
+\def\p@stkeysr@nd{%
+   \@rderr@nd%                  last < first  -> swap
+   \cutr@nger@nd%               range too big -> cut
+   \@ifundefined{c@\r@ndcountername}{\newcounter{\r@ndcountername}}%
+   {%
+      \PackageWarning{lcg}{Using an already existing
+           counter \r@ndcountername}%
+   }%
+\setcounter{\r@ndcountername}{0}%
+} % end of \def\p@stkeysr@nd
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{firstletter}
+% This macro is used to determine the first letter of the value
+% of the key \key{quiet}.
+%    \begin{macrocode}
+\def\firstletterr@nd#1#2\delimiter{#1}
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{@utput}
+% Output to log-file/screen
+%    \begin{macrocode}
+\def\@utputr@nd{%
+   \if\qui@t y
+      % do nothing
+   \else
+     \typeout{Smallest possible random number: \the\f@rst}%
+     \typeout{Largest possible random number:  \the\l@st}%
+     \typeout{The pseudo random numbers will be stored
+      in the LaTeX counter `\r@ndcountername'}%
+   \fi
+}
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{@rder}
+% If the value of the key \key{last} is less than
+% the value of \key{first},  they will be exchanged.
+%    \begin{macrocode}
+\def\@rderr@nd{%
+   \ifnum \l@st < \f@rst%
+       \PackageWarning{lcg}{Key `last' less than key `first'
+               -- swapped}%
+       \@tempcnta = \f@rst
+       \f@rst = \l@st
+       \l@st = \@tempcnta
+   \fi%
+}%   end of \def\@rderr@nd
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{cutr@nge}
+% If the given range of random numbers exceeds the possibilities
+% of \LaTeX\ (the limit is $2^{31}-1$), then the value of the \TeX-counter
+% \cntr{@tempcnta} will be less than zero and the right border will be adjusted.
+%    \begin{macrocode}
+\def\cutr@nger@nd{%
+   \@tempcntb =  -2147483646   % -2^31 + 2
+   \@tempcnta = \f@rst
+   \advance \@tempcntb \l@st
+   \multiply \@tempcntb \m@ne
+   \advance \@tempcnta \@tempcntb
+   \ifnum \@tempcnta < \z@%
+      \PackageWarning{lcg}{Range contains too many numbers
+                     -- right border reset to largest possible value}%
+      \advance \l@st \@tempcnta
+   \fi%
+
+}%   end of \checkr@ange
+%    \end{macrocode}
+% \end{macro}
+%
+%
+% \subsection{Macros for random number generation}
+%
+% \begin{macro}{rand}
+% The command \cmd{\rand} calls the internal command
+% \cmd{\r@nd} which stores s random number (full range)
+% within the counter \cntr{cr@nd}.
+% If the condition
+% $$
+% \mathtt{cr@nd} \leq (\mathtt{l@st}-\mathtt{f@rst}+1)
+% \cdot \frac{2^{31}-1}{\mathtt{l@st}-\mathtt{f@rst}+1}
+% $$
+% holds,  \cntr{cr@nd} will be transformed
+% to the given range:
+% $$
+%  \mathtt{f@rst}+ \mathtt{cr@nd} - (\mathtt{l@st}-\mathtt{f@rst}+1)
+%  \cdot \frac{\mathtt{cr@nd}}{\mathtt{l@st}-\mathtt{f@rst}+1}
+% $$
+% and the result stored in the corresponding counter
+% and otherwise \cmd{\rand} calls itself till the condition
+% is satisfied. It's important
+% to notice that the result of the division of two integers is
+% again an integer (the fraction part is lost)!
+%
+%    \begin{macrocode}
+\def\rand{%
+   \r@nd%
+   \@tempcnta
+   \@tempcntb
+   \@tempcnta = \f@rst
+   \@tempcntb = \l@st
+   \multiply \@tempcnta \m@ne
+   \advance \@tempcntb \@tempcnta
+   \advance \@tempcntb \@ne         %l@st-f@rst+1
+   \@tempcnta = 2147483647
+   \divide \@tempcnta \@tempcntb
+   \multiply \@tempcnta \@tempcntb
+   \ifnum \cr@nd > \@tempcnta
+      \rand%
+   \else
+      \setcounter{\r@ndcountername}{\cr@nd}%
+      \@tempcnta = \cr@nd
+      \divide \@tempcnta \@tempcntb
+      \multiply \@tempcnta \@tempcntb
+      \multiply \@tempcnta \m@ne
+      \addtocounter{\r@ndcountername}{\@tempcnta}%
+      \addtocounter{\r@ndcountername}{\f@rst}%
+   \fi
+} % end of \rand
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{r@nd}
+% The command \cmd{\r@nd} generates pseudo random numbers within
+% the range  $1$ to $2^{31}-1$ Schrage's method and stores them
+% in the counter  \cntr{cr@nd}:
+%
+%    \begin{macrocode}
+\def\r@nd{%
+   \ifnum \cr@nd < \@ne%       then  ... initialize generator
+      \cr@nd = \the\time
+      \advance \cr@nd  \inputlineno
+      \multiply \cr@nd  \thepage
+      \advance \cr@nd \the\year
+      \multiply \cr@nd \the\month
+      \multiply \cr@nd \the\day
+      \advance \cr@nd \inputlineno
+      \if\qui@t y
+      \else
+         \typeout{Random number generator initialized to \the\cr@nd}%
+      \fi
+      \r@nd%
+   \else                         %  else ... generate new number
+      \@tempcnta = \cr@nd
+      \divide \@tempcnta  127773    % \@tempcnta = floor(z/q)
+      \@tempcntb = \@tempcnta       % \@tempcntb = floor(z/q)
+      \multiply \@tempcnta  -2836   % \@tempcnta = -r*floor(z/q)
+      \multiply \@tempcntb -127773  % \@tempcntb = -q*floor(z/q)
+      \advance \cr@nd \@tempcntb    % cr@nd = z mod q
+      \multiply \cr@nd 16807        % cr@nd = a * (z mod q)
+      \advance \cr@nd \@tempcnta    % cr@nd = a*z mod m
+      \ifnum \cr@nd < \z@%
+         \advance \cr@nd 2147483647 % cr@nd = (a*z mod m) > 0
+      \fi
+   \fi
+}%        end of \r@nd
+%    \end{macrocode}
+% \end{macro}
+%
+%
+% \subsection{Initialization}
+%
+%    \begin{macrocode}
+\initr@nd      % initialize the package
+%    \end{macrocode}
+%
+% \iffalse
+%</lcg>
+% \fi
diff --git a/Master/texmf-dist/source/latex/lcg/lcg.ins b/Master/texmf-dist/source/latex/lcg/lcg.ins
new file mode 100644
index 00000000000..1f937263a5e
--- /dev/null
+++ b/Master/texmf-dist/source/latex/lcg/lcg.ins
@@ -0,0 +1,12 @@
+%% File: lcg.ins Copyright (C) 2000 Erich Janka (janka@utanet.at)

+%%

+%% Docstrip installation instruction file for `lcg' 

+

+\input docstrip

+\keepsilent

+\askforoverwritefalse

+\preamble

+\endpreamble

+\generate{\file{lcg.sty}{\from{lcg.dtx}{lcg}}}

+\endbatchfile

+