% \iffalse
%% Class aipproc to use with LaTeX2e
%%
%% Copyright (C) 1998, 2000, 2001 Frank Mittelbach
%% Copyright (C) 1998, 2000, 2001 American Institute of Physics, all rights reserved.
%%
%% Development of this class was commissioned by American Institute of Physics.
%%
%
%<class>\NeedsTeXFormat{LaTeX2e}[1999/06/01]
%<class>\ProvidesClass{aipproc}
%<class>       [2001/12/21 v1.3a AIP Proceedings (FMi)]
% \fi
% \def\filedate{2001/12/21}
% \def\fileversion        {v1.3a}
% \iffalse
%
% \subsection{The documentation driver file}
%
%    The next bit of code contains the documentation driver file for
%    \TeX{}, i.e., the file that will produce the documentation you are
%    currently reading. It will be extracted from this file by the 
%    \texttt{docstrip} program.
%    \begin{macrocode}
%<*driver>
\documentclass{aipdoc}
\usepackage{array,tabularx}
\usepackage{color}
\usepackage{hyperref}
\setlength\MacroIndent{24pt}
\setlength\parindent{0pt}
\setlength\hfuzz{1pt}    % ignore slight overfulls
\CodelineIndex
\EnableCrossrefs         
%\DisableCrossrefs   % Say \DisableCrossrefs if index is ready

\RecordChanges       % Gather update information
%\OnlyDescription    % comment out for implementation details
\begin{document}
   \DocInput{aipproc.dtx}
\end{document}
%</driver>
%    \end{macrocode}
%
% \fi
%
%
%% \CharacterTable
%%  {Upper-case    \A\B\C\D\E\F\G\H\I\J\K\L\M\N\O\P\Q\R\S\T\U\V\W\X\Y\Z
%%   Lower-case    \a\b\c\d\e\f\g\h\i\j\k\l\m\n\o\p\q\r\s\t\u\v\w\x\y\z
%%   Digits        \0\1\2\3\4\5\6\7\8\9
%%   Exclamation   \!     Double quote  \"     Hash (number) \#
%%   Dollar        \$     Percent       \%     Ampersand     \&
%%   Acute accent  \'     Left paren    \(     Right paren   \)
%%   Asterisk      \*     Plus          \+     Comma         \,
%%   Minus         \-     Point         \.     Solidus       \/
%%   Colon         \:     Semicolon     \;     Less than     \<
%%   Equals        \=     Greater than  \>     Question mark \?
%%   Commercial at \@     Left bracket  \[     Backslash     \\
%%   Right bracket \]     Circumflex    \^     Underscore    \_
%%   Grave accent  \`     Left brace    \{     Vertical bar  \|
%%   Right brace   \}     Tilde         \~}
%%
%
%
%
% \MakeShortVerb\|
%
% \title{The \texttt{aipproc} class\thanks{This file
%        has version number \fileversion, last
%        revised \filedate.}}
% \author{Frank Mittelbach}
% \date{\filedate}
%
% \maketitle
%
%
% \tableofcontents
%
% \section{Introduction}
%
% The \texttt{aipproc} class is a \LaTeXe{} document class for
% conference proceedings of the American Institute of Physics. It is
% intended to produce camera-ready copy for direct photo-offset
% use. The only modification done by the AIP is adding appropriate
% page numbers.
% 
% The class provides the underlying layer that allows implementation
% of the layouts as specified in \emph{Author Instruction for
% Preparation of Camera Ready Manuscripts, Conference Proceedings}.
% With the exception of the frontmatter
% handling it provides essentially the same markup as
% implemented by \LaTeX's standard \texttt{article} class.  In
% addition to this it implements the following:
% \begin{itemize}
% \item extended set of front matter commands,
% \item automatic placement of floats into column or page areas
%   including turning of table floats by 90$^\circ$ if necessary,
% \item allows mixing column and page-wide floats without getting the
%   numbering out of sync,
% \item footnotes will appear below bottom floats,
% \item support for table notes,
% \item support for textual page references like ``on the next page''.
% \end{itemize}
% 
%
%
% \StopEventually{\PrintChanges}
%
%
%
% \section{The Implementation}
%
%
%
% \subsection{Preliminaries}
%
% Two-column mode in \LaTeX{} does have some (known and
% documented\footnote{Called features in such a case.}) defects: For
% example floats could get out of order if one is mixing single column
% and double column floats. The package \texttt{fix2col} attempts to
% fix this and other problems.  This package was integrated into the
% package \texttt{fixltx2e} which is part of the standard distribution
% of \LaTeX{} these days.
% 
% So we check if this package is available and if so load it,
% otherwise we try loading \texttt{fix2col}.
%
%    \begin{macrocode}
%<*class>
\IfFileExists{fixltx2e.sty}
  {\RequirePackage{fixltx2e}}
  {\RequirePackage{fix2col}[1998/08/17]}
%    \end{macrocode}
%
%    Unfortunately the first versions of \texttt{fixltx2e} contained
%    some major bugs, so we have to check if we have the very recent
%    version available. If not we fix the package manually. The
%    internally available interfaces in the kernel are a bit flacky
%    for this, so we first have to test if the package was loaded at
%    all (otherwise |\@ifpackagelater| would die) then have to check
%    the date of the package (again slightly strange, we can't use the
%    date of the last known bad version since the test it is in fact
%    not for ``later'' but ``not earlier''). And, by the way, we can't
%    move the code into the branch of |\IfFileExists| since that would
%    die due to |#| in the argument.
%    \begin{macrocode}
\@ifpackageloaded{fixltx2e}{%
\@ifpackagelater{fixltx2e}{1999/12/02}{}{%
%    \end{macrocode}
%    Here is the code that was incorrect in the version of 1999/12/01:    
%    \begin{macrocode}
\def\addpenalty#1{%
  \ifvmode
    \if@minipage
    \else
      \if@nobreak
      \else
        \ifdim\lastskip=\z@
          \penalty#1\relax
        \else
          \@tempskipb\lastskip
          \advance \@tempskipb
               \ifdim\prevdepth>\maxdepth\maxdepth\else
                 \ifdim \prevdepth = -\@m\p@ \z@ \else \prevdepth \fi
               \fi
          \vskip -\@tempskipb
          \penalty#1%
          \vskip\@tempskipb
        \fi
      \fi
    \fi
  \else
    \@noitemerr
  \fi}
%    \end{macrocode}
%    
%    \begin{macrocode}
\def \@doclearpage {%
     \ifvoid\footins
       \setbox\@tempboxa\vsplit\@cclv to\z@ \unvbox\@tempboxa
       \setbox\@tempboxa\box\@cclv
       \xdef\@deferlist{\@toplist\@botlist\@deferlist}%
       \global \let \@toplist \@empty
       \global \let \@botlist \@empty
       \global \@colroom \@colht
       \ifx \@currlist\@empty
       \else
          \@latexerr{Float(s) lost}\@ehb
          \global \let \@currlist \@empty
       \fi
       \@makefcolumn\@deferlist
       \@whilesw\if@fcolmade \fi{\@opcol\@makefcolumn\@deferlist}%
       \if@twocolumn
         \if@firstcolumn
           \xdef\@deferlist{\@dbltoplist\@deferlist}%
           \global \let \@dbltoplist \@empty
           \global \@colht \textheight
           \begingroup
              \@dblfloatplacement
              \@makefcolumn\@deferlist
              \@whilesw\if@fcolmade \fi{\@outputpage
                                        \@makefcolumn\@deferlist}%
           \endgroup
         \else
           \vbox{}\clearpage
         \fi
       \fi
       \ifx\@deferlist\@empty \else\clearpage \fi
     \else
       \setbox\@cclv\vbox{\box\@cclv\vfil}%
       \@makecol\@opcol
       \clearpage
     \fi
}
%    \end{macrocode}
%    
%    \begin{macrocode}
\def \@addtocurcol {%
   \@insertfalse
   \@setfloattypecounts
   \ifnum \@fpstype=8
   \else
     \ifnum \@fpstype=24
     \else
       \@flsettextmin
       \advance \@textmin \@textfloatsheight
       \@reqcolroom \@pageht
       \ifdim \@textmin>\@reqcolroom
         \@reqcolroom \@textmin
       \fi
       \advance \@reqcolroom \ht\@currbox
       \ifdim \@colroom>\@reqcolroom
         \@flsetnum \@colnum
         \ifnum \@colnum>\z@
           \@bitor\@currtype\@deferlist
          \@testwrongwidth\@currbox
           \if@test
           \else
             \@bitor\@currtype\@botlist
             \if@test
               \@addtobot
             \else
               \ifodd \count\@currbox
                 \advance \@reqcolroom \intextsep
                 \ifdim \@colroom>\@reqcolroom
                   \global \advance \@colnum \m@ne
                   \global \advance \@textfloatsheight \ht\@currbox
                   \global \advance \@textfloatsheight 2\intextsep
                   \@cons \@midlist \@currbox
                   \if@nobreak
                     \nobreak
                     \@nobreakfalse
                     \everypar{}%
                   \else
                     \addpenalty \interlinepenalty
                   \fi
                   \vskip \intextsep
                   \box\@currbox
                   \penalty\interlinepenalty
                   \vskip\intextsep
                   \ifnum\outputpenalty <-\@Mii \vskip -\parskip\fi
                   \outputpenalty \z@
                   \@inserttrue
                 \fi
               \fi
               \if@insert
               \else
                 \@addtotoporbot
               \fi
             \fi
           \fi
         \fi
       \fi
     \fi
   \fi
   \if@insert
   \else
     \@resethfps
     \@cons\@deferlist\@currbox
   \fi
}}}
%    \end{macrocode}
%    If \texttt{fixltx2e} wasn't loaded there is nothing to do.
%    \begin{macrocode}
{}
%    \end{macrocode}
%
%
%
% Before handling options we need to load some packages used later on:
%    \begin{macrocode}
\RequirePackage{calc}
\RequirePackage{ifthen}
\RequirePackage[final]{graphicx}
%    \end{macrocode}
%
% By default natbib is load if possible.
%    \begin{macrocode}
\newif\if@load@natbib \@load@natbibtrue
%    \end{macrocode}
%    
%    \begin{macrocode}
\IfFileExists{url.sty}
  {\RequirePackage{url}%
  }
  {\def\url##1{\texttt{##1}}%
   \ClassWarningNoLine{aipproc}
      {\noexpand\url command might fail with
        this LaTeX \MessageBreak installation since url.sty 
        is missing}%
  }
%    \end{macrocode}
%
%
% And some commands to signal errors and warnings:
%    \begin{macrocode}
\newcommand\AIP@optionnotsupported[1]
    {\ClassWarningNoLine{aipproc}%
                {Option~ `#1'~ not~ supported~ ---~ request~ ignored}}
%    \end{macrocode}
%    \begin{macrocode}
\newcommand\AIP@error{\ClassError{aipproc}}
\newcommand\AIP@cmdnotsupported[1]
    {\def#1{\AIP@error{Command \noexpand#1not supported by
                       class}\@eha}}
\newcommand\AIP@natbibnotavailable[1]
    {\def#1{\AIP@error{Command \noexpand#1not supported if natbib
                       not installed}\@eha}}
%    \end{macrocode}
%
%  \begin{macro}{\DesignerError}
%  \begin{macro}{\InformationError}
%    The following three functions can be used to generate certain
%    type of error messages and warning messages for this class.
%    \begin{macrocode}
\newcommand*\DesignerError[1]{%
  \AIP@error{#1}{Probably bug in class file.}}
\newcommand*\InformationError[1]{%
  \AIP@error{#1}%
    {Add the necessary information to the document.}}
%    \end{macrocode}
%  \end{macro}
%  \end{macro}
%
%
%  \begin{macro}{\MakeSpaceIgnore}
%    Change |~| to produce a space and ignore normal spaces and
%    newlines.
%    \begin{macrocode}
\newcommand\MakeSpaceIgnore{%
    \catcode`\~=10\relax
    \catcode`\ = 9\relax
    \catcode`\^^M = 9\relax
}
%    \end{macrocode}
%  \end{macro}
%
%  \begin{macro}{\MakeSpaceNormal}
%    Undo the effects of |\MakeSpaceIgnore|.
%    \begin{macrocode}
\newcommand\MakeSpaceNormal{%
    \catcode`\~= 13\relax
    \catcode`\ = 10\relax
    \catcode`\^^M = 5\relax
}
%    \end{macrocode}
%  \end{macro}
%
%
%  \begin{macro}{\UnbreakableSpace}
%    Keep a copy of the normal meaning of |~| around so that it can be
%    used in strings.
%    \begin{macrocode}
\let\UnbreakableSpace~
%    \end{macrocode}
%  \end{macro}
%
%    And activate this code for the rest of the file.
%    \begin{macrocode}
\MakeSpaceIgnore
%    \end{macrocode}
%
%
%
% \subsection{Option handling}
%
% First we disable article options that are not appropriate for this
% class:
%    \begin{macrocode}
\DeclareOption{a5paper}       {\AIP@optionnotsupported\CurrentOption}
\DeclareOption{b5paper}       {\AIP@optionnotsupported\CurrentOption}
\DeclareOption{legalpaper}    {\AIP@optionnotsupported\CurrentOption}
\DeclareOption{executivepaper}{\AIP@optionnotsupported\CurrentOption}
\DeclareOption{landscape}     {\AIP@optionnotsupported\CurrentOption}
\DeclareOption{10pt}          {\AIP@optionnotsupported\CurrentOption}
\DeclareOption{11pt}          {\AIP@optionnotsupported\CurrentOption}
\DeclareOption{12pt}          {\AIP@optionnotsupported\CurrentOption}
\DeclareOption{titlepage}     {\AIP@optionnotsupported\CurrentOption}
\DeclareOption{notitlepage}   {\AIP@optionnotsupported\CurrentOption}
\DeclareOption{oneside}       {\AIP@optionnotsupported\CurrentOption}
\DeclareOption{twoside}       {\AIP@optionnotsupported\CurrentOption}
\DeclareOption{onecolumn}     {\AIP@optionnotsupported\CurrentOption}
\DeclareOption{twocolumn}     {\AIP@optionnotsupported\CurrentOption}
\DeclareOption{leqno}         {\AIP@optionnotsupported\CurrentOption}
\DeclareOption{fleqn}         {\AIP@optionnotsupported\CurrentOption}
\DeclareOption{openbib}       {\AIP@optionnotsupported\CurrentOption}
%    \end{macrocode}
%
% Next two options define the numbering scheme for table notes:
%    \begin{macrocode}
\DeclareOption{tnotealph}  {\def\AIP@tnote@representation{\@alph}}
\DeclareOption{tnotesymbol}{\def\AIP@tnote@representation{\@fnsymbol}}
%    \end{macrocode}
%
% Handling math fonts:
%    \begin{macrocode}
\newboolean{@cmrfonts}
\DeclareOption{cmfonts}    {\setboolean{@cmrfonts}{true}
                            \def\AIP@mathfontsused{0}}
\DeclareOption{mathptm}    {\def\AIP@mathfontsused{1}}
\DeclareOption{mathtime}   {\def\AIP@mathfontsused{2}}
\DeclareOption{nomathfonts}{\def\AIP@mathfontsused{3}}
\DeclareOption{mathptmx}   {\def\AIP@mathfontsused{4}}
%    \end{macrocode}
%
% Page references will either use varioref or get disabled, so we can
% hijack |\pageref| as a signal:
%    \begin{macrocode}
\def\pageref{0}
\DeclareOption{varioref}      {\def\pageref{1}}
\DeclareOption{nonvarioref}   {\def\pageref{2}}
%    \end{macrocode}
%
% Citations will either be in numerical style or ``author-year''
% (bibliographic) style.
%    \begin{macrocode}
\DeclareOption{numcites}      {\def\AIPcitestyleselect{num}}
\DeclareOption{bibliocites}   {\def\AIPcitestyleselect{biblio}}
%    \end{macrocode}
%    If the site as only a very old natbib installation that doesn't
%    work with this class we can prevent it from loading if really necessary.
%    \begin{macrocode}
\DeclareOption{nonatbib}      {\dont@load@natbibfalse}
%    \end{macrocode}
%
% Headings will be either numbered or unnumbered (the particular value
%    of |-3| might get overwritten by the layout file later on).
%    \begin{macrocode}
\DeclareOption{numberedheadings}    
    {\AtEndOfClass{\setcounter{secnumdepth}{3}}}
\DeclareOption{unnumberedheadings}
    {\AtEndOfClass{\setcounter{secnumdepth}{-\maxdimen}}}
%    \end{macrocode}
%
% The draft option does whatever draft does in the article class and
% in addition will allow page references and places a footer line on
% every page.
%    \begin{macrocode}
\DeclareOption{draft}{\PassOptionsToClass{\CurrentOption}{article}%
    \@drafttrue
    \AtEndOfPackage{
          \let\AIP@pagenumerror\@gobble
          \def\@oddfoot{\reset@font
            \AIPfoliofont
            \AIPfolioformat\@shorttitle\@date\thepage
            }}}
\newif\if@draft
\DeclareOption{final}{\PassOptionsToClass{\CurrentOption}{article}}
%    \end{macrocode}
%
%    All other options are passed to the article class for further
%    processing
%    \begin{macrocode}
\DeclareOption*{\PassOptionsToClass{\CurrentOption}{article}}
%    \end{macrocode}
% Execute the defaults and
% then process the document options.
%    \begin{macrocode}
\ExecuteOptions{mathptmx,tnotesymbol,numcites,unnumberedheadings,letterpaper}
\ProcessOptions\relax
%    \end{macrocode}
% Then load the article class as the base class.
%    \begin{macrocode}
\MakeSpaceNormal
\LoadClass{article}
\MakeSpaceIgnore
%    \end{macrocode}
%
% \begin{macro}{\layoutstyle}
%    Parameter settings for a particular layout are not done in class
%    file itself. Instead it is done by calling |\layoutstyle|.
%    \begin{macrocode}
\def\layoutstyle#1{%
    \expandafter\let\expandafter
       \AIP@layoutstylename
       \csname AIP@layout@style@#1 \endcsname
%    \end{macrocode}
%    If no mapping for the layout style name is defined we try the
%    name directly.
%    \begin{macrocode}
    \ifx\AIP@layoutstylename\relax
       \def\AIP@layoutstylename{#1}
    \fi
    \MakeSpaceIgnore
    \makeatletter
    \InputIfFileExists{aip-\AIP@layoutstylename.clo}
        {\let\AIP@check@layoutstyle\relax}
        {\AIP@error{The~ layout~ style~ `#1'~ is~ not~
                    known\MessageBreak  or~ its~
                    support~ file~ can~ not~ be~ found}
         {The~ \noexpand \layoutstyle command~ tried~ to~ load~ the~ file~
          aip-\AIP@layoutstylename.clo~ without~ success!\MessageBreak
          This~ might~ be~ due~ to~ misspelling~ the~ style~ 
          name.\MessageBreak
          Standard~ styles~ are~ `6x9',~ `8x11single',~ 
          `8x11double',~ and~ `arlo',~ but\MessageBreak there~
           might~ be~ others~ (see~ the~ class~
          documentation).\MessageBreak
          It~ could~ also~ be~ due~ to~ an~ incomplete~ installation~
          of~ the~ class.
         }
        }
    \MakeSpaceNormal
    \makeatother
    \ifdim\columnsep>\z@
       \@twocolumntrue
    \else
       \@twocolumnfalse
    \fi
}
\@onlypreamble\layoutstyle
%    \end{macrocode}
%    Define some mappings for the layout styles so that short file
%    names are loaded.
%    \begin{macrocode}
\def\declare@layoutstyle#1#2{
  \@namedef{AIP@layout@style@#1}{#2}
}
\@onlypreamble\declare@layoutstyle
%    \end{macrocode}
%    
%    \begin{macrocode}
\declare@layoutstyle{6x9}{6s}
\declare@layoutstyle{8x11single}{8s}
\declare@layoutstyle{8x11double}{8d}
%    \end{macrocode}
%    
%    We need to see a |\layoutstyle| declaration in the preamble so we
%    better check for it. |\layoutstyle| will redefine the next
%    command if it was able to load a style.
%    \begin{macrocode}
\def\AIP@check@layoutstyle{
  \AIP@error{No~ \noexpand\layoutstyle command~ seen}
    {The~ class~ requires~ a~ \noexpand\layoutstyle{<name>}~ 
     declaration~ in~ the~ preamble!\MessageBreak
     Standard~ styles~ are~ `6x9',~ `8x11single',~ 
    `8x11double',~ and~ `arlo',~ but\MessageBreak there~
     might~ be~ others~ (see~ the~ class~
     documentation).\MessageBreak
     To~ be~ able~ to~ proceed~ the~ 6x9~ style~ is~ assumed.  
    }
    \layoutstyle{6x9}
%    \end{macrocode}
%    But we are a little late so some of the work done in |\document|
%    needs to be repeated.
%    \begin{macrocode}
  \@colht\textheight
  \@colroom\textheight \vsize\textheight
  \columnwidth\textwidth
  \@clubpenalty\clubpenalty
  \if@twocolumn
    \advance\columnwidth -\columnsep
    \divide\columnwidth\tw@ \hsize\columnwidth \@firstcolumntrue
  \fi
  \hsize\columnwidth \linewidth\hsize
}
\AtBeginDocument{\AIP@check@layoutstyle}
%    \end{macrocode}
% \end{macro}
%
%
%
% \subsection{General support commands}
%
% \subsubsection{Setting registers}
%
%  \begin{macro}{\SetInternalRegister}
%    A way to set internal registers of all kind. With \texttt{calc}
%    in use one can also define special versions for `counters' etc
%    that can handle arithmetic. See below.
%    \begin{macrocode}
\newcommand*\SetInternalRegister[2]{#1=#2\relax}
%    \end{macrocode}
%  \end{macro}
%
%
%  \begin{macro}{\SetInternalCounter}
%    This macro would allow arguments like |5+\value{totalauthors}| etc.
%    Actually it isn't used in the parameter section since there was
%    no need for it but that might change with a different layout.
%    \begin{macrocode}
\let\SetInternalCounter\count@assign
%    \end{macrocode}
%  \end{macro}
%
%
% \subsubsection{Paragraph layout support}
%
% The paragraph layouts are internally stored in macros named in the
% following way: |\|\meta{para-name}|Para|. However this is hidden
% from the user who is supposed to use |\UseParagraphLayout| to access
% a named layout. 
%
% The implementation isn't too effective and could be improved with
% some more thought. Due to a clean interface that can transparently
% happen anytime.
%
%  \begin{macro}{\DeclareParagraphLayout}
%    \begin{macrocode}
\newcommand*\DeclareParagraphLayout[9]{%
    \@namedef{#1Para}{
	  \fontsize{#2}{#3}\selectfont
          #9
	  \setlength\parindent  {#4}
	  \setlength\leftskip   {#5}
	  \setlength\rightskip  {#6}
	  \@rightskip\rightskip
	  \setlength\parfillskip{#7}
	  \setlength\parskip    {#8}
	}
}
%    \end{macrocode}
%    This command should be only used before |\begin{document}|.
%    \begin{macrocode}
\@onlypreamble\DeclareParagraphLayout
%    \end{macrocode}
%  \end{macro}
%
%
%  \begin{macro}{\UseParagraphLayout}
%    Check if the paragraph layout was defined, if not complain
%    otherwise use it.
%    \begin{macrocode}
\newcommand*\UseParagraphLayout[1]{
    \@ifundefined{#1Para}
       {\DesignerError{Paragraph~ layout~ '#1'~ undefined}}
       {\@nameuse{#1Para}}
}
%    \end{macrocode}
%  \end{macro}
%
%
%  \begin{macro}{\DeclareParagraphLayoutAlias}
%    Check that the second name is defined as a paragraph layout. If
%    so produce an alias using |\let|.
%    \begin{macrocode}
\newcommand*\DeclareParagraphLayoutAlias[2]{%
      \@ifundefined{#2Para}
           {\DesignerError{Paragraph~ layout~ '#2'~ undefined}}
           {\expandafter\let
              \csname#1Para\expandafter\endcsname
              \csname#2Para\endcsname
           }
}
\@onlypreamble\DeclareParagraphLayoutAlias
%    \end{macrocode}
%  \end{macro}
%
%
% \subsubsection{Baseline to baseline skips}
%
%  \begin{macro}{\UseBBskip}
%    This command is only allowed in vertical mode, so the usual
%    sequence in a macro definition is:
%\begin{verbatim}
%   ...
%   \par                              % end para if necessary
%   \DeclareParagraphLayout{...}      % define new para values
%   \UseBBskip{...}                   % skip from previous para
%\end{verbatim}
%    possibly surrounded by groups to keep changes local. It is
%    important to change the paragraph values first (if they should
%    change) otherwise the skip will not be correct.
%    \begin{macrocode}
\newcommand*\UseBBskip[1]
  {\ifvmode
%    \end{macrocode}
%    Calculate the skip necessary then issue it.
%    \begin{macrocode}
    \setlength\@tempskipa{#1 - \parskip - \baselineskip}
    \vskip\@tempskipa
   \else
    \DesignerError{\protect\UseBBskip\space outside~ vmode}
   \fi
  }
%    \end{macrocode}
%  \end{macro}
%
%
%
%
%
% \subsubsection{Page Style Support}
%
%
%  \begin{macro}{\DeclarePagestyle}
%    This declaration is just doing a little housekeeping and could be
%    improved by adding checks etc. --- actually not used right now.
%    \begin{macrocode}
\newcommand*\DeclarePagestyle[5]
  {
   \@namedef{ps@#1}
     {
      \def\@oddhead {#2}
      \def\@oddfoot {#3}
      \def\@evenhead{#4}
      \def\@evenfoot{#5}
     }
   }
%    \end{macrocode}
%  \end{macro}
%
%
% \subsubsection{General layout registers}
%
%    To help structuring layout files a number of registers are
%    available.
%    \begin{macrocode}
\newdimen\bodytextsize
\newdimen\bodytextbaselineskip
\newdimen\bodytextenspace     
\newdimen\bodytextparindent   
%    \end{macrocode}
%
%
%
% \subsection{Page styles}
%
%    No running header or footer; so select empty page style and
%    disable the |\pagestyle| command altogether. The draft option
%    overwrites this with a low-level call.
%    \begin{macrocode}
\pagestyle{empty}
\AIP@cmdnotsupported\pagestyle
%    \end{macrocode}
%
%
%
%
% \subsection{Front matter}
%
%
% |\tableofcontents| and the like are disabled, or rather produce an 
% error message before doing their work, except in draft mode:
%    \begin{macrocode}
\newcommand\AIP@pagenumerror[1]{%
  \AIP@error{Command~ \string#1~ can't~ be~ used~ 
       in~ production}%
      {This~ command~ will~ produce~ page~ numbers~ which~ will~
       be~ incorrect~ in~ the\MessageBreak final~ production.
       It~ should~ therefore~ only~ be~ used~ while~ producing~
       drafts.}}
\let\@@tableofcontents\tableofcontents
\let\@@listoffigures\listoffigures
\let\@@listoftables\listoftables
%    \end{macrocode}
%
%    \begin{macrocode}
\renewcommand\tableofcontents{%
   \AIP@pagenumerror\tableofcontents\@@tableofcontents}
\renewcommand\listoffigures{%
   \AIP@pagenumerror\listoffigures\@@listoffigures}
\renewcommand\listoftables{%
   \AIP@pagenumerror\listoftables\@@listoftables}
%    \end{macrocode}
%
%    Main code for frontmatter is handled in the package \texttt{aipxfm}.
%    \begin{macrocode}
\RequirePackage{aipxfm}
\MakeSpaceIgnore
%    \end{macrocode}
%
%    
%
% \subsection{Headings}
%
%    Headings are constructed viy |\AIP@startsection| which is a
%    variant of the standard |\@startsection| command.
%    \begin{macrocode}
\def\AIP@startsection#1#2#3#4#5{
    \@tempskipa#2\relax 
    \advance\@tempskipa-\parskip
    \ifdim\@tempskipa<\z@
      \DesignerError{#2~ -~ \protect\parskip needs~ to~ be~
                     non-negative}
    \fi
    \ifthenelse{\equal#1{true}}
      \relax
      {\@tempskipa-\@tempskipa}
    \edef\AIP@preskip{\the\@tempskipa}
    \@tempskipa#4\relax
    \advance\@tempskipa-\parskip
    \ifdim\@tempskipa<\z@
      \DesignerError{#2~ -~ \protect\parskip needs~ to~ be~
                     non-negative}
    \fi
    \ifthenelse{\equal#3{true}}
      {\@tempskipa-\@tempskipa}
      \relax
    \edef\AIP@postskip{\the\@tempskipa}
    \@secpenalty#5\relax
    \@startsection
}
%    \end{macrocode}
%    
%    \begin{macrocode}
\renewcommand\section
   {\AIP@startsection
      \AIPsectionafterindent\AIPsectionpreskip
      \AIPsectionrunin\AIPsectionpostskip
      \AIPsectionpenalty
       {section}{1}{\AIPsectionindent}%
                   {\AIP@preskip}%
                   {\AIP@postskip}%
                   {\AIPsectionfont\AIPsectionformat}}
%    \end{macrocode}
%    
%    \begin{macrocode}
\renewcommand\subsection
   {\AIP@startsection
      \AIPsubsectionafterindent\AIPsubsectionpreskip
      \AIPsubsectionrunin\AIPsubsectionpostskip
      \AIPsubsectionpenalty
    {subsection}{2}{\AIPsubsectionindent}%
                   {\AIP@preskip}%
                   {\AIP@postskip}%
                   {\AIPsubsectionfont\AIPsubsectionformat}}
%    \end{macrocode}
%    
%    \begin{macrocode}
\renewcommand\subsubsection
   {\AIP@startsection
      \AIPsubsubsectionafterindent\AIPsubsubsectionpreskip
      \AIPsubsubsectionrunin\AIPsubsubsectionpostskip
      \AIPsubsubsectionpenalty
    {subsubsection}{3}{\AIPsubsubsectionindent}%
                   {\AIP@preskip}%
                   {\AIP@postskip}%
                   {\AIPsubsubsectionfont\AIPsubsubsectionformat}}
%    \end{macrocode}
%
% Next two are not defined in the spec but why not provide them
%    \begin{macrocode}
\renewcommand\paragraph
   {\AIP@startsection
      \AIPparagraphafterindent\AIPparagraphpreskip
      \AIPparagraphrunin\AIPparagraphpostskip
      \AIPparagraphpenalty
     {paragraph}{4}{\AIPparagraphindent}%
                   {\AIP@preskip}%
                   {\AIP@postskip}%
                   {\AIPparagraphfont\AIPparagraphformat}}
%    \end{macrocode}
%    
%    \begin{macrocode}
\renewcommand\subparagraph
   {\AIP@startsection
      \AIPsubparagraphafterindent\AIPsubparagraphpreskip
      \AIPsubparagraphrunin\AIPsubparagraphpostskip
      \AIPsubparagraphpenalty
  {subparagraph}{5}{\AIPsubparagraphindent}%
                   {\AIP@preskip}%
                   {\AIP@postskip}%
                   {\AIPsubparagraphfont\AIPsubparagraphformat}}
%    \end{macrocode}
%    
%
%
%  \begin{macro}{\UseNoHyphens}
%    This macro will turn off any hyphenation.
%    \begin{macrocode}
\newcommand\UseNoHyphens{\hyphenpenalty\@M\exhyphenpenalty\@M}
%    \end{macrocode}
%  \end{macro}
%
%
%
%
% \subsection{Fonts}
%
% Depending on the value of |\AIP@mathfontsused| we 
% load different math fonts: 0 means
% use Computer Modern for everything; 1 means use the \texttt{mathptm}
% package; 2 means use the commercial MathTime fonts; and 3 means use
% Computer Modern for math but Times Roman for text.
%    \begin{macrocode}
\ifcase \AIP@mathfontsused
                                 % 0 use cm for everything
\or
\MakeSpaceNormal
  \RequirePackage{mathptm}       % 1
\MakeSpaceIgnore
\or
\MakeSpaceNormal
  \RequirePackage{mathtime}      % 2
\MakeSpaceIgnore
\or
                                 % 3 use cm for math
\or
\MakeSpaceNormal
  \RequirePackage{mathptmx}      % 4
\MakeSpaceIgnore
\fi
%    \end{macrocode}
% As said above Times is used for text unless |\AIP@mathfontsused| is
% 0 in which case we don't do any font setup whatsoever, i.e., leave
% everything to user specification in the preamble.
% \changes{1998/11/12}{v1.0b}{Load fontenc only after the times package
%     to avoid that people running into problems if they don't have the
%     EC fonts installed}
%    \begin{macrocode}
\ifnum \AIP@mathfontsused > 0
  \RequirePackage{times}
  \normalfont
  \RequirePackage[T1]{fontenc}
  \RequirePackage{textcomp}
\fi
%    \end{macrocode}
%
% \subsection{Body text}
%
%    We install the main paragraph layout once we have seen
%    |\begin{document}|.
%    \begin{macrocode}
\AtBeginDocument{\UseParagraphLayout{AIPbodytext}}
%    \end{macrocode}
%
%
% \subsection{Footnotes}
%
%    The |\footnoterule| command needs a special definition to get the
%    rule in the right place---lazy coding.
%    \begin{macrocode}
\renewcommand\footnoterule{
  \setlength\skip@{\AIPfootnoteruleheight+\AIPfootnoterulepostskip}
  \vskip-\skip@
  \moveright \AIPfootnoteruleindent\vbox{%
    \hrule \@width \AIPfootnoterulewidth 
           \@height \AIPfootnoteruleheight}%
  \vskip \AIPfootnoterulepostskip \relax}
%    \end{macrocode}
%
%    \begin{macrocode}
\AtBeginDocument{
  \setlength{\skip\footins}{\AIPfootnoterulepreskip
                            +\AIPfootnoterulepostskip}}
%    \end{macrocode}
%
%    \begin{macrocode}
\renewcommand\@makefntext[1]{
    \UseParagraphLayout{AIPfootnote}
    \noindent
    \hbox{\AIPfootnotetextmarkerformat
             {\AIPfootnotetextmarkerfont\@thefnmark}}%
    \ignorespaces
    #1}
%    \end{macrocode}
%    
%    \begin{macrocode}
\def\@makefnmark{\hbox{%
  \AIPfootnotemarkerformat{\AIPfootnotemarkerfont\@thefnmark}}}
%    \end{macrocode}
%    
% \subsubsection{Output routine changes}
%
% The following redefinition of the output routine makes footnotes 
% come out below of bottom floats.
%    \begin{macrocode}
\def \@makecol {%
   \setbox\@outputbox \box\@cclv
   \@combinefloats
   \ifvoid\footins
   \else
     \setbox\@outputbox \vbox {%
       \boxmaxdepth \@maxdepth
       \unvbox \@outputbox
       \vskip \skip\footins
       \color@begingroup
         \normalcolor
         \footnoterule
         \unvbox \footins
       \color@endgroup
       }%
   \fi
   \xdef\@freelist{\@freelist\@midlist}%
   \global \let \@midlist \@empty
   \ifvbox\@kludgeins
     \@makespecialcolbox
   \else
     \setbox\@outputbox \vbox to\@colht {%
       \@texttop
       \dimen@ \dp\@outputbox
       \unvbox \@outputbox
       \vskip -\dimen@
       \@textbottom
       }%
   \fi
   \global \maxdepth \@maxdepth
}
%    \end{macrocode}
%
%
%
%
% \subsection{Counters}
%
% The counter representation commands |\@alph| and |\@fnsymbol| are
% extended to support more possibilities.
%
%    \begin{macrocode}
\def\@fnsymbol#1{\ensuremath{\ifcase#1\or *\or \dagger\or **\or 
   \ddagger\or \mathsection\or \mathparagraph\or \|\or \dagger\dagger
   \or \ddagger\ddagger \or\mathsection\mathsection
   \or \mathparagraph\mathparagraph \or *{*}*\or
   \dagger{\dagger}\dagger \or\ddagger{\ddagger}\ddagger\or
   \mathsection{\mathsection}\mathsection 
   \or \mathparagraph{\mathparagraph}\mathparagraph \else\@ctrerr\fi}}
%    \end{macrocode}
%    \begin{macrocode}
\def\@alph#1{\ifcase#1\or a\or b\or c\or d\or e\or f\or g\or h\or i\or
  j\or k\or l\or m\or n\or o\or p\or q\or r\or s\or t\or u\or v\or
  w\or x\or y\or z\or aa\or bb\or cc\or dd\or ee\or ff\or gg\or hh\or
  ii\or jj\or kk\or ll\or mm\or nn\or oo\or pp\or qq\or rr\or ss\or
  tt\or uu\or vv\or ww\or xx\or yy\or zz\else\@ctrerr\fi}
%    \end{macrocode}
%
%
%
%
% \subsection{Math}
%
%    The support for the |\eqref| command needs to be deferred until
%    start of the document since the user might have added the
%    \texttt{amsmath} package.
%    \begin{macrocode}
\AtBeginDocument{%
  \ifx\tagform@\@undefined
    \def\eqref#1{\mbox{\AIPeqreffont\AIPeqrefformat{\ref{#1}}}}%
  \else
    \def\tagform@#1{\mbox{\AIPeqreffont
      \AIPeqrefformat{\ignorespaces
                      #1\unskip\@@italiccorr}}}%
%    \end{macrocode}
%    In case switching tags to the left more work would be necessary
%    at this point
%    \begin{macrocode}
  \fi
  \def\@eqnnum{{\AIPeqfont\AIPeqformat\theequation}}
}
%    \end{macrocode}
%    
%
%
%
%
% \subsection{Minipages}
%
% No changes
%    \begin{macrocode}
%    \end{macrocode}
%
%
%
%
% \subsection{Lists}
%
% Defaults are used.
%
%
%
% \subsection{References}
%
% Page references are either disabled (if |\pageref| is 0 at this
% point) or the |\varioref| package is used to allow for textual page
% references.
%    \begin{macrocode}
\ifnum\pageref>0
 \MakeSpaceNormal
  \RequirePackage{varioref}
 \MakeSpaceIgnore
%    \end{macrocode}
% Customize varioref strings so that they don't talk about ``facing''
% pages as in this class the final page numbers are not known.
%    \begin{macrocode}
 \renewcommand\reftextfaceafter {on~ the~ next~ page}
 \renewcommand\reftextfacebefore{on~ the~ \reftextvario{previous}
                                                     {preceding}~ page}
 \renewcommand\reftextafter     {on~ the~ \reftextvario{following}
                                                     {next}~ page}
 \renewcommand\reftextbefore    {on~ the~ \reftextvario{preceding~ page}
                                                     {page~ before}}
 \renewcommand\reftextcurrent   {on~ \reftextvario{this}%
                                                 {the~ current}~ page}
%    \end{macrocode}
% |\reftextfaraway| needs a more drastic redefinition since we have to
% find out if we reference earlier or later pages.
%    \begin{macrocode}
 \renewcommand\reftextfaraway[1]{%
%    \end{macrocode}
%
% We know that page numbers are always numbers in this class
% (so we either have a number or \texttt{??}) and we know that they are
% stored in |\@tempa| and |\@tempb| so we can test if we refer back or
% forward:
%    \begin{macrocode}
   \is@pos@number\@tempb
    {\ifnum\@tempb<0\@tempa\relax
       \reftextearlier
     \else
       \reftextlater
     \fi}%
%    \end{macrocode}
% if |\@tempb| does not contain number we produce a warning using
% the command also used by |\ref| for this.
%    \begin{macrocode}
   {\@setref\relax\relax{#1}}}
%    \end{macrocode}
%
% With the above redefinition we have two new strings that need
% textual definitions:
%    \begin{macrocode}
 \newcommand\reftextearlier{\reftextvario{on~ an~ earlier~ page}
                                         {earlier~ on}}
 \newcommand\reftextlater  {\reftextvario{later~ on}{further~ down}}
%    \end{macrocode}
% If |\pageref| is 2 the user has requested to omit variations in the
% generated strings. We implement this by choosing always the first variant:
%    \begin{macrocode}
 \ifnum\pageref=2
   \def\reftextvario#1#2{#1}
 \fi
%    \end{macrocode}
% After all this prelims we finally give a sensible meaning to |\pageref|:
%    \begin{macrocode}
 \let\pageref\vpageref
%    \end{macrocode}
%
% So now for the case that |\pageref| was 0, i.e., no page references.
%    \begin{macrocode}
\else
  \renewcommand\pageref[1]
    {\AIP@error{Page~ references~ not~ supported}
      {This~ class~ does~ not~ support~ references~ to~ page~
       numbers~ unless~ the~ varioref~ or~ the~ nonvarioref~ option~ 
       is~ used,~ since~ it~ doesn't~ print~ page~ numbers.}}
\fi
%    \end{macrocode}
%
%
%
%
% \subsection{Floats}
%
%
% \subsubsection{Caption handling}
%
% We have different caption formatting for tables and figures.
%    \begin{macrocode}
\newcommand\AIP@maketablecaption[2]{%
  \UseParagraphLayout{AIPtable-singlelinecaption}
  \settowidth\@tempdima{%
      \noindent
      {\AIPtablecaptionheadfont\AIPtablecaptionheadformat{#1}}
      \AIPtablecaptiontextfont\ignorespaces#2}
  \ifdim\@tempdima>\hsize
     \UseParagraphLayout{AIPtable-multilinecaption}
  \fi
  \noindent
  {\AIPtablecaptionheadfont\AIPtablecaptionheadformat{#1}}
  \AIPtablecaptiontextfont\ignorespaces#2\par
  \vskip\AIPtablecaptionskip}
%    \end{macrocode}
%    
%    \begin{macrocode}
\newskip\AIPtablecaptionskip
%    \end{macrocode}
%
%    \begin{macrocode}
\newcommand\AIP@makefigurecaption[2]{%
  \UseParagraphLayout{AIPfigure-singlelinecaption}
  \UseBBskip\AIPfigurecaptionBBskip
  \settowidth\@tempdima{%
      \noindent
      {\AIPfigurecaptionheadfont\AIPfigurecaptionheadformat{#1}}
      \AIPfigurecaptiontextfont\ignorespaces#2}
  \ifdim\@tempdima>\hsize
     \UseParagraphLayout{AIPfigure-multilinecaption}
  \fi
  \noindent
  {\AIPfigurecaptionheadfont\AIPfigurecaptionheadformat{#1}}
  \AIPfigurecaptiontextfont\ignorespaces#2\par
}
%    \end{macrocode}
%    
%    \begin{macrocode}
\newskip\AIPfigurecaptionBBskip
%    \end{macrocode}
%
%
%
% \subsubsection{The source command}
%
% The |\source| command is supported within the table and the figure
% environment but not elsewhere.
%    \begin{macrocode}
\newcommand\AIP@sourceerror{\AIP@error
  {\noexpand\source is only supported with `table' or `figure' 
   environment}\@ehd}
\let\source\AIP@sourceerror
%    \end{macrocode}
%
%
%    \begin{macrocode}
\newcommand\AIP@fsource@setup{%
    \def\source##1{\gdef\AIP@typeset@source
      {\addvspace\AIPfiguresourceskip
       \rightline{\AIPfiguresourceheadfont \AIPfiguresourceheadtext
                  \AIPfiguresourcetextfont ##1}
      }}
    \global\let\AIP@typeset@source\@empty}
%    \end{macrocode}
%
%
%    \begin{macrocode}
\newcommand\AIP@tsource@setup{%
    \def\source##1{\gdef\AIP@typeset@source
      {\addvspace\AIPtablesourceskip
       \rightline{\AIPtablesourceheadfont \AIPtablesourceheadtext
                  \AIPtablesourcetextfont ##1}
      }}
    \global\let\AIP@typeset@source\@empty}
%    \end{macrocode}
%
%
% \subsubsection{Table notes and column headers}
%
% Table notes are only supported within the table environment.
%    \begin{macrocode}
\newcommand\AIP@tablenoteerror{\AIP@error
  {\noexpand\tablenote is only supported inside `table' 
   environment\MessageBreak and not allowed inside
   the \noexpand\caption or \noexpand\source command}\@ehd}
\let\tablenote\AIP@tablenoteerror
%    \end{macrocode}
%
% The internal definition takes two arguments, the first defines
% whether the note marker occupies any space (by supplying |\rlap| 
% or |\relax|).
%    \begin{macrocode}
\newcommand\AIP@tablenote[2]{%
       \leavevmode
       \stepcounter\@mpfn
       \protected@xdef\@thefnmark{\thempfn}%
       #1\@footnotemark
       \protected@xdef\AIP@tnote@process
            {\AIP@tnote@process
             \protect\footnotetext
               [\the\c@mpfootnote]
               {\protect\UseParagraphLayout{AIPtablenote}#2}}%
}
%    \end{macrocode}
%
%    \begin{macrocode}
\newcommand\AIP@tnote@setup{%
    \def\@mpfn{mpfootnote}%
    \def\thempfn{\thempfootnote}%
    \def\thempfootnote{\AIP@tnote@representation\c@mpfootnote}%
    \global\c@mpfootnote\z@
    \def\tablenote{\@ifstar{\AIP@tablenote\relax}
                           {\AIP@tablenote\rlap}}
    \gdef\AIP@tnote@process{}%
    \setlength{\skip\@mpfootins}{\AIPtablenoteskip}
    \let\footnoterule\relax
    \let\@footnotetext\@mpfootnotetext
}
%    \end{macrocode}
%    
%    \begin{macrocode}
\newskip\AIPtablenoteskip
%    \end{macrocode}
%
% This is the internal definition for the |\tablehead| command. It is
% essentially a tabular environment within a |\multicolumn|
% command. The strange |\vrule| commands add some space above and
% below (not the most sophisticated definition possible :-).
%    \begin{macrocode}
\newcommand\AIP@tablehead[4]{\multicolumn{#1}{#2}%
   {\AIPtableheadfont\begin{tabular}[#3]{@{}#2@{}}%
    \vrule \@height \bodytextsize\@width \z@\relax
    \ignorespaces#4\unskip
    \vrule \@depth .5\bodytextsize\@width \z@\end{tabular}}}
%    \end{macrocode}
%
% We redefine |\hline| slightly by allowing for some additional space
% above and below the rule. As typically more space is needed below
% this is not distributed evenly.
%    \begin{macrocode}
\def\hline{%
  \noalign{\ifnum0=`}\fi\vskip\AIPhlinesep
      \hrule \@height \arrayrulewidth\vskip3\AIPhlinesep
      \futurelet \reserved@a\@xhline}
\newdimen\AIPhlinesep
%    \end{macrocode}
%
%
% \subsubsection{Tables}
%
% The \texttt{ltxtable} and \texttt{ltxtable*} environment implement,
% except for font setup, the original \LaTeX{} table environments.
%    \begin{macrocode}
\newenvironment{ltxtable}
               {\@float{table}
                \let\tablehead\AIP@tablehead
                \let\@makecaption\AIP@maketablecaption
                \AIPtablefont}
               {\end@float}
\newenvironment{ltxtable*}
               {\@dblfloat{table}
                \let\tablehead\AIP@tablehead
                \let\@makecaption\AIP@maketablecaption
                \AIPtablefont}
               {\end@dblfloat}
%    \end{macrocode}
%
% \texttt{table*} environment is not supported by this class.
%    \begin{macrocode}
\renewenvironment{table*}[1][tbp]
   {\AIP@error{Environment `table*' not supported\MessageBreak
                         --- environment `table' used instead}%
    {The class automatically determines the position of the float 
     according\MessageBreak
     to its size.}%
    \begin{table}}
   {\end{table}}
%    \end{macrocode}
%
% And here the new definition for the table environment. It captures
% the body into and horizontal box, storing any |\label| or |\caption|
% command in some save place.
%    \begin{macrocode}
\renewenvironment{table}[1][tbp]
   {\def\AIP@floatspec{#1}%
    \let\tablehead\AIP@tablehead
    \let\@makecaption\AIP@maketablecaption
    \AIP@tsource@setup
    \AIP@tnote@setup
    \global \setbox\AIP@box
    \color@hbox
      \hbox \bgroup
      \@floatboxreset
         \def\caption##1{\gdef\AIP@save@caption{##1}}%
         \def\label##1{\gdef\AIP@save@label{##1}}%
         \global\let\AIP@save@caption\@undefined
         \global\let\AIP@save@label\@undefined
       \normalcolor
       \AIPtablefont
       \ignorespaces
   }
   {%
       \AIP@remove@any@previous@space
       \outer@nobreak
      \egroup
    \color@endbox
%    \end{macrocode}
% At this place the float body is in |\AIP@box|, caption text in
% |\AIP@save@caption|, any source info in |\AIP@typeset@source|,
% etc. We now have to determine how to typeset all this.
%
% The following code distinguishes between the width of |\AIP@box| being
% \begin{itemize}
% \item less or equal than |\columnwidth|,
% \item bigger than |\columnwidth| but less or
% equal than |\textwidth|, and
% \item bigger than |\textwidth|.
% \end{itemize}
%
% Actually the tests are for |\columnwidth+1pt|, etc.\ because it
% turned out that commands like |\resizebox| are not completely
% accurate so that 
%\begin{verbatim}
%   \resizebox{\columnwidth}{!}...
%\end{verbatim}
%  may end up being a
% tiny bit bigger than |\columnwidth|. This is in fact mainly a
% problem with the \texttt{figure} environment but we allow some
% rounding errors here as well.
%    \begin{macrocode}
    \setlength\dimen@{\columnwidth+1pt}%
    \ifdim\wd\AIP@box >\dimen@
      \setlength\dimen@{\textwidth+1pt}%
      \ifdim\wd\AIP@box >\dimen@
        \def\@captype{table}%
        \sbox\@tempboxa{\AIP@make@table@body}%
        \setlength\dimen@{\ht\@tempboxa+\dp\@tempboxa}%
%    \end{macrocode}
% If the width is bigger than |\textwidth| we test if the height is
% small enough to fit into a column. If so we turn the float and make
% it a column float.
%    \begin{macrocode}
        \ifdim\dimen@ <\columnwidth
          \def\@tempa{\@float{table}}%
          \expandafter\@tempa\expandafter[\AIP@floatspec]%
            \centerline{\rotatebox{90}{\box\@tempboxa}}%
          \end@float
%\typeout{single chosen}%
%    \end{macrocode}
% Otherwise we turn it but make it a double column float. If even after
% turning the width is wider than |\textwidth| the user will have a problem
% since this means that the table is both to wide and to high. In that case
% the code will turn and \LaTeX{} will produce some overfull box (inclusive
% a warning).
%    \begin{macrocode}
        \else
           \def\@tempa{\@dblfloat{table}}%
           \expandafter\@tempa\expandafter[\AIP@floatspec]%
%           \centerline{\rotatebox{90}{\box\@tempboxa}}%
           \setbox\@tempboxa\hbox{\rotatebox{90}{\box\@tempboxa}}
%    \end{macrocode}
%    Test if table is still too wide (allowing 5pt grace):
%    \begin{macrocode}
           \dimen@\wd\@tempboxa
           \advance\dimen@ -5\p@   % grace
           \ifdim \dimen@ >\textwidth
             \AIP@error{Table~ too~ wide~ (\the\wd\@tempboxa\space 
                        >~\the\textwidth)}
                {Table~ doesn't~ fit~ even~ after~ turning~ it~ 
                 by~ 90~ degrees.~ You~ probably\MessageBreak
                 have~ to~ change~ it~ somewhat.}
           \fi
           \centerline{\unhbox \@tempboxa}
          \end@dblfloat
%\typeout{double chosen}%
        \fi
%    \end{macrocode}
% Here we have something which is suitable for a double column float\ldots
%    \begin{macrocode}
      \else
        \def\@tempa{\@dblfloat{table}}%
        \expandafter\@tempa\expandafter[\AIP@floatspec]%
          \AIP@make@table@body
        \end@dblfloat
      \fi
%    \end{macrocode}
% \ldots and finally this branch is taken if the width is not bigger than
% |\columnwidth|; so make it a column float.
%    \begin{macrocode}
    \else
      \def\@tempa{\@float{table}}%
      \expandafter\@tempa\expandafter[\AIP@floatspec]%
        \AIP@make@table@body
      \end@float
    \fi
} 
%    \end{macrocode}
%
% The next macro implements the formatting of body and caption:
%    \begin{macrocode}
\newcommand\AIP@make@table@body{%
      \centering
      \@tempdima\wd\AIP@box
%    \end{macrocode}
%
% By default the caption is typeset to the width of the table, however
% if the table is too small we typeset it wider:
%    \begin{macrocode}
      \ifdim\@tempdima<\AIPtablecaptionminwidth 
        \@tempdima\AIPtablecaptionminwidth
      \fi
      \begin{minipage}\@tempdima
        \ifx\AIP@save@caption\@undefined\else
          \let\tablenote\AIP@tablenoteerror
          \caption{\AIP@save@caption
                   \ifx\AIP@save@label\@undefined\else
                     \label\AIP@save@label
                   \fi}%
        \fi
        \par
        \offinterlineskip                % or we get \lineskip
        \vbox{\hsize\wd\AIP@box
                          \box\AIP@box
                          \AIP@typeset@source}%
        \AIP@tnote@process
     \end{minipage}%
}
\newdimen\AIPtablecaptionminwidth
%    \end{macrocode}
%
% Some helper macro used above that removes stray spaces 
% as long as they are  positive (the name is not quite right).
%    \begin{macrocode}
\newcommand\AIP@remove@any@previous@space
  {\unskip\loop\unskip\ifdim\lastskip>\z@\repeat}
%    \end{macrocode}
%
%
%    
%    \begin{macrocode}
\newbox\AIP@box
%    \end{macrocode}
%
%
%
% \subsubsection{Figures}
%
% Implementation of figures is more or less the same as for tables,
% except there we don't have the complication of turning the body if
% it gets too wide (it just better doesn't get too wide).
%    \begin{macrocode}
\newenvironment{ltxfigure}
               {\@float{figure}
                \let\@makecaption\AIP@makefigurecaption}
               {\end@float}
\newenvironment{ltxfigure*}
               {\@dblfloat{figure}
                \let\@makecaption\AIP@makefigurecaption}
               {\end@dblfloat}
%    \end{macrocode}
%    \begin{macrocode}
\renewenvironment{figure}[1][tbp]
   {\def\AIP@floatspec{#1}%
    \AIP@fsource@setup
    \global \setbox\AIP@box
    \color@hbox
      \hbox \bgroup
      \@floatboxreset
         \def\caption##1{\gdef\AIP@save@caption{##1}}%
         \def\label##1{\gdef\AIP@save@label{##1}}%
         \global\let\AIP@save@caption\@undefined
         \global\let\AIP@save@label\@undefined
       \normalcolor
       \normalfont
       \normalsize
       \ignorespaces
   }
   {%
       \AIP@remove@any@previous@space
       \outer@nobreak
      \egroup
    \color@endbox
    \def\@tempa{\@dblfloat{figure}}%
    \setlength\dimen@{\columnwidth+1pt}%
    \ifdim\wd\AIP@box >\dimen@
      \expandafter\@tempa\expandafter[\AIP@floatspec]%
        \AIP@make@figure@body
      \end@dblfloat
    \else
      \def\@tempa{\@float{figure}}%
      \expandafter\@tempa\expandafter[\AIP@floatspec]%
        \AIP@make@figure@body
      \end@float
    \fi
} 
%    \end{macrocode}
%    \begin{macrocode}
\renewenvironment{figure*}{\figure}{\endfigure}
%    \end{macrocode}
%    \begin{macrocode}
\newcommand\AIP@make@figure@body{%
      \centering
%    \end{macrocode}
% The need to account for rounding errors from the graphics package
% was explained above. Though this may get fixed one day\ldots
%    \begin{macrocode}
      \setlength\@tempdima{\wd\AIP@box-1pt}%
%    \end{macrocode}
%
% The next bit would center the caption as a block depending on size
% of the figure\ldots
%    \begin{macrocode}
%      \ifdim\@tempdima<.7\columnwidth \@tempdima.7\columnwidth
%      \else
%        \ifdim\@tempdima<\columnwidth \@tempdima\columnwidth \fi
%      \fi
%    \end{macrocode}
% \ldots while the code below always justifies to column or page width.
% The command to typeset the figure caption then as some additional
% logic for centering the caption text if it fits on a single line
%    \begin{macrocode}
      \ifdim\@tempdima>\columnwidth 
         \@tempdima\textwidth
      \else
         \@tempdima\columnwidth
      \fi
      \begin{minipage}\@tempdima
        \centerline{\vbox{\hsize\wd\AIP@box
                          \box\AIP@box
                          \AIP@typeset@source}}%
        \ifx\AIP@save@caption\@undefined\else
          \let\@makecaption\AIP@makefigurecaption
          \caption{\AIP@save@caption
                   \ifx\AIP@save@label\@undefined\else
                     \label\AIP@save@label
                   \fi}%
        \fi
        \par
     \end{minipage}}
%    \end{macrocode}
%
%    \begin{macrocode}
\renewcommand\fnum@figure{\thefigure}
\renewcommand\fnum@table{\thetable}
%    \end{macrocode}
%
%
% The next commands makes an empty box of the right size to leave 
% room for an illustion that will get pasted in manually later.
% \changes{1998/11/12}{v1.0b}{Define command cs{spaceforfigure}}
%    \begin{macrocode}
\newcommand\spaceforfigure[2]{\parbox{#1}{\mbox{}\vspace*{#2}}}
%    \end{macrocode}
%
%
%
% 
% \subsubsection{Long table support}
%
% The user has to load the longtable package manually in the
% preamble. What we do here is to overwrite some of its commands and
% make sure that our redefinitions are executed only after the package
% got loaded.
%    \begin{macrocode}
\AtBeginDocument{%
\newcommand\@@longtable{}%
\let\@@longtable\longtable
%
\def\longtable{%
%    \end{macrocode}
% Better don't look too closely into that code, it calculates the
% width of the table if known and assigns it to |\LTcapwidth|.
%    \begin{macrocode}
  \begingroup
    \LTcapwidth\z@
    \advance\c@LT@tables\@ne   % local as stepcounter comes later
    \let\LT@entry\AIP@get@longtable@width
    \csname LT@\romannumeral\c@LT@tables\endcsname
    \ifdim \LTcapwidth=\z@ \global \LTcapwidth2in
    \else \global\LTcapwidth\LTcapwidth
    \fi
  \endgroup
  \AIPtablefont
%    \end{macrocode}
% We support |\tablehead| command and that's it.
%    \begin{macrocode}
  \let\tablehead\AIP@tablehead
  \@@longtable
}%
%    \end{macrocode}
% |\LT@makecaption| is used to typeset the caption so we better make
% this look like other captions for this class.
%    \begin{macrocode}
\def\LT@makecaption#1#2#3{%
  \LT@mcol\LT@cols {@{}l@{}}{\rlap{\parbox[t]\LTcapwidth{%
  \UseParagraphLayout{AIPtable-multilinecaption}
  \noindent
  {\AIPtablecaptionheadfont\AIPtablecaptionheadformat{#1#2}}
  \AIPtablecaptiontextfont\ignorespaces#3\endgraf
  \vspace*\AIPtablecaptionskip
  }}}}%
%    \end{macrocode}
%    
%    \begin{macrocode}
\def\LT@hline{%
  \noalign{\ifnum0=`}\fi
    \penalty\@M\vskip\AIPhlinesep
    \futurelet\@let@token\LT@@hline}
\def\LT@@hline{%
  \ifx\@let@token\hline
    \global\let\@gtempa\@gobble
    \gdef\LT@sep{\penalty-\@medpenalty\vskip\doublerulesep}%
  \else
    \global\let\@gtempa\@empty
    \gdef\LT@sep{\penalty-\@lowpenalty\vskip-\arrayrulewidth}%
  \fi
  \ifnum0=`{\fi}%
  \multispan\LT@cols
     \unskip\leaders\hrule\@height\arrayrulewidth\hfill\cr
  \noalign{\LT@sep}%
  \multispan\LT@cols
     \unskip\leaders\hrule\@height\arrayrulewidth\hfill\cr
  \noalign{\penalty\@M\vskip3\AIPhlinesep}%
  \@gtempa}
}
%    \end{macrocode}
% And here a helper to get to the right caption width.
%    \begin{macrocode}
\newcommand\AIP@get@longtable@width[2]{\advance\LTcapwidth#2\relax }
%    \end{macrocode}
%
%
%
%
% \subsection{Acknowledgments}
%
% \begin{environment}{theacknowledgements}
%    That's a simple one.
%    \begin{macrocode}
\newenvironment{theacknowledgments}
     {\AIPacknowledgmentsheadtype\AIPacknowledgmentsheadtext
      \UseParagraphLayout{AIPacknowledgments}}
     {\par}
%    \end{macrocode}
% \end{environment}
%      
%
%
%
% \subsection{Index}
%
% \begin{environment}{theindex}
%     Nothing very fancy here.
%    \begin{macrocode}
\renewenvironment{theindex}
               {
                \if@twocolumn
                  \@restonecolfalse
                  \AIPindexheadtype\indexname
                \else
                  \columnseprule \z@
                  \columnsep 35\p@
                  \@restonecoltrue
                  \twocolumn[\AIPindexheadtype\indexname]
                \fi
                \parindent\z@
                \parskip\z@ \@plus .3\p@\relax
                \let\item\@idxitem}
               {\if@restonecol\onecolumn\fi}
%    \end{macrocode}
% \end{environment}
%
%
% \subsection{Bibliography}
%
%    The bibliography handling for this class assumes that the
%    \texttt{natbib} system is available. If not, we have to give up
%    for some journal styles.
%    \begin{macrocode}
\IfFileExists{natbib.sty}
  {
   \if@load@natbib
%    \end{macrocode}
%    If \texttt{natbib} is around we use its |\citestyle| command at
%    |\begin{document}| to select the right citation style for the
%    journal. But we have to do this before loading \texttt{natbib}
%    itself since that puts stuff into the document hook and we need
%    to execute |\citestyle| prior to this point (messy).
%    \begin{macrocode}
     \AtBeginDocument{
        \citestyle
           {\csname AIP \AIPcitestyleselect citestyle\endcsname}
     }
%    \end{macrocode}
%    Now load \texttt{natbib} with normal spacing rules.
%    \begin{macrocode}
    \MakeSpaceNormal
    \RequirePackage{natbib}
    \MakeSpaceIgnore
   \fi
   }{}
%    \end{macrocode}
%    Now we check if |\citet| is defined. If not, we haven't been able
%    to load \texttt{natbib} (the code below can't be placed into
%    |\IfFileExists| since that command doesn't like |#| marks in its
%    arguments, sigh.)
%    \begin{macrocode}
\ifx\citet\@undefined
   \def\citet{\AIP@natbibnotavailable\citet}
   \def\citep{\AIP@natbibnotavailable\citep}
   \def\citealt{\AIP@natbibnotavailable\citealt}
   \def\citealp{\AIP@natbibnotavailable\citealp}
   \def\citetext{\AIP@natbibnotavailable\citetext}
   \def\citeauthor{\AIP@natbibnotavailable\citeauthor}
   \def\citeyear{\AIP@natbibnotavailable\citeyear}
   \def\citeyearpar{\AIP@natbibnotavailable\citeyearpar}
   \def\Citet{\AIP@natbibnotavailable\Citet}
   \def\Citep{\AIP@natbibnotavailable\Citep}
   \def\Citealt{\AIP@natbibnotavailable\Citealt}
   \def\Citealp{\AIP@natbibnotavailable\Citealp}
   \def\Citetext{\AIP@natbibnotavailable\Citetext}
   \def\Citeauthor{\AIP@natbibnotavailable\Citeauthor}
   \def\Citeyear{\AIP@natbibnotavailable\Citeyear}
   \def\Citeyearpar{\AIP@natbibnotavailable\Citeyearpar}
%    \end{macrocode}
% 
%
%    This code is close to the original \LaTeX{} one with the modifications
%    necessary to implement the class layout (as far as possible
%    without \texttt{natbib}).
%    \begin{macrocode}
   \renewenvironment{thebibliography}[1]
     {\AIPbibliographyheadtype\refname
      \list{\AIPbibliographymarkerformat{\@arabic\c@enumiv}}%
           {\settowidth\labelwidth{\AIPbibliographymarkerformat{#1}}%
            \UseParagraphLayout{AIPbibliography}
            \leftmargin\labelwidth
            \advance\leftmargin\labelsep
            \setlength\itemsep\AIPbibliographyitemsep
            \@openbib@code
            \usecounter{enumiv}%
            \let\p@enumiv\@empty
            \renewcommand\theenumiv{\@arabic\c@enumiv}}%
      \sfcode`\.\@m}
     {\def\@noitemerr
       {\@latex@warning{Empty `thebibliography' environment}}%
      \endlist}
%    \end{macrocode}
%    
%
%    The citations in text are formatted according to |\AIPcitelayout|
%    using the |\AIPcitefont|.
%    \begin{macrocode}
  \renewcommand*\@cite[2]{{\AIPcitefont
     \AIPciteformat{#1\if@tempswa , #2\fi}}}
%    \end{macrocode}
%    We definitely can't do author/year citation styles. But even
%    numerical ones might be wrong, e.g., the arlo one wants
%    superscripts.
%    \begin{macrocode}
  \AtBeginDocument{
        \ifthenelse{\equal\AIPcitestyleselect{num}}
           {}
           {\AIP@error{Author/year~ citation~ style~ impossible}
              {Without~ the~ natbib~ system~ only~ numerical~ citations~ are~
               possible.~ But~ you~ (or~ the~ journal~ \string\layoutstyle)~
               requested~ a~ diffferent~ citation~ style.}
           }
    }
%    \end{macrocode}
%    But if |\citet| was defined, we have \texttt{natbib} available so
%    now it is only a matter of changing a few dozen lines of that
%    system to get what we want :-)
%    \begin{macrocode}
\else
   \renewcommand\bibsection{\AIPbibliographyheadtype\refname}
   \renewcommand\NAT@bibsetnum[1]{
      \ifdim\AIPbibliographylabelwidth=\maxdimen
	\settowidth\labelwidth{\@biblabel{#1}}
        \setlength\leftmargin\labelwidth
      \else
        \setlength\labelwidth\AIPbibliographylabelwidth
        \setlength\leftmargin
          {\AIPbibliographyleftmargin+\AIPbibliographyleftmarginextra}
        \setlength\itemindent{-\AIPbibliographyleftmarginextra}
      \fi
      \addtolength\leftmargin\AIPbibliographylabelsep
      \setlength\labelsep\AIPbibliographylabelsep
      \setlength\itemsep\AIPbibliographyitemsep
      \UseParagraphLayout{AIPbibliography}
      \setlength\parsep{\parskip}
   }
  \renewcommand\NAT@bibsetup[1]{
       \setlength\leftmargin
          {\AIPbibliographyleftmargin+\AIPbibliographyleftmarginextra}
       \setlength\itemindent{-\AIPbibliographyleftmarginextra}
       \setlength\itemsep\AIPbibliographyitemsep
       \UseParagraphLayout{AIPbibliography}
       \setlength\parsep{\parskip}
      }
%    \end{macrocode}
%    The above is a bit crude; it is especialy tailored to the needs
%    of the journal styles so far implemented, but\ldots
%
%    A few citation styles that we might want to use in the parms sections.
%    \begin{macrocode}
  \newcommand\bibstyle@arlonum{\bibpunct{}{}{,}{s}{}{\textsuperscript{,}}%
     \gdef\NAT@biblabelnum##1{\textsuperscript{##1}}
     \gdef\thefootnote{\alph{footnote}}
  }
  \newcommand\bibstyle@aipproc{\bibpunct{[}{]}{,}{n}{}{,}
     \gdef\NAT@biblabelnum##1{##1.\hfill}}
\fi
%    \end{macrocode}
%
%
% We finish with making the space being a space again.
%    \begin{macrocode}
\MakeSpaceNormal
%</class>
%    \end{macrocode}
%
%
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%
%
%
%
%
% \PrintIndex
% \Finale
%
\endinput