
 \CompHEP~ uses the {\it Axodraw} package by J.A.M.~Vermaseren  \cite{axodraw} 
to write diagrams and plots in \LaTeX~ format. To use this package the 
{\it Axodraw}
 style  should be included in the {\it documentstyle} statement. 
An example would be 

{\tt	{$\backslash$}documentstyle[axodraw]\{article\} }

%The original source and full documentation  can be  got by {\it anonymous ftp} 
%from  the {\it  ftp.nikhef.nl}  site of the  directory 
%{\it pub/theory/form/axodraw}. 
Under  kind   permission of the author we put a copy of  {\it axodraw.sty} file 
in  the \$COMPHEP/ directory.
One bug in the axis drawing routine has been  corrected.    

    The {\it Axodraw} syntax is very easy and you can alter the \CompHEP~ 
output to get some local correction in picture if any.  The user can also 
change  line width,  scale of picture, and  size of characters. The
corresponding \LaTeX~ and {\it Axodraw} instructions are presented 
in the beginning of the output. For example,
\begin{verbatim}
{  \small              % letter  size control
   \SetWidth{0.7}      % line  width control
   \SetScale{1.0}      % line scale control
   \unitlength=1.0 pt  % text position control
   ............
}
\end{verbatim} 

Note that the  {\it {$\backslash$}SetScale}  instruction influences 
on  positions of lines, whereas the {\it {$\backslash$}unitlength} variable
is responsible for position if texts. Consequently, if  the user would like
to change the scale of picture, he must improve these instructions 
in the same manner.   For instance, to increase the picture by two times use 
\begin{verbatim}
   \SetScale{2.0}      % picture size control
   \unitlength=2.0 pt  % picture size control
\end{verbatim} 

In the case of Feynman diagram output \CompHEP~ substitutes \LaTeX~ 
names of particles as they are defined in the {\it Particle} table 
(see Section \ref{particles}).
