
The \CompHEP~ project  was founded in 1989 by the group of 
 physicists and programmers of D.V. Skobeltsyn Institute of Nuclear
Physics of
Moscow State University.  The project was initiated by Edward Boos,
 Viacheslav Ilyin  and  Victor Savrin. The primary formulation of  
physical problems  for the project was done by E.~Boos, Mikhail Dubinin, and
Dmitri Slavnov.
The first software working group was organized and managed by V.~Ilyin.

    The main author of the \CompHEP~ software is Alexander Pukhov.
He has developed almost all algorithms and data-representation 
structures  of the package. Namely, the structure  of physical
model database, the algorithm for generation of Feynman diagrams, 
the algorithm for evaluation of squared matrix elements, the structure 
of output codes for different programming languages, 
the algorithm for optimization of numerical codes, the algorithm for 
phase-space integration with smoothing of propagator peaks. He also has
created  the specialized   symbolic manipulation package for \CompHEP.

  The first version of the package appeared in 1989 \cite{First,AIHENP1}.
It was written  in the {\it Turbo Pascal} programming language for 
the {\it  MS-DOS}  operation system. The program produced a code
for calculation of squared  diagrams, written in  the \REDUCE~
symbolic manipulation language.    Routines for evaluation of the color
factors
 were written by Alexander Kryukov. The \REDUCE~ code-generation 
routines were written by Alexander Taranov and A.~Pukhov.

The authors of \CompHEP~ were being lead by an idea to create a user
friendly software. So they paid a special attention
to the interface and data-representation facilities.
The general part of graphical interface was  designed  by A.~Pukhov.
 The routines  for graphic representation of diagrams
were written by Victor Edneral.  The context-sensitive help facility
was designed by Sergey Shichanin. The program for the \CompHEP~ database
table manipulation was done by A.~Kryukov. Later on 
the plot drawing and \LaTeX~ output were designed  by
V.~Edneral, A.~Pukhov and S.~Shichanin.  


The  \CompHEP~ symbolic answers were compared by Mikhail Dubinin
with a large number of  known symbolic 
expressions for  differential  and integral cross sections 
\cite{sCompare}. Starting from this point 
the physicists of \CompHEP~ group  E.~Boos, M.~Dubinin, and
V.~Ilyin applied \CompHEP~ for studying  new physics signals and relevant 
backgrounds.
 
 In 1991 \CompHEP~ got the built-in symbolic 
manipulation package created by A.~Pukhov and the \FORTRAN~
code output written by A.~Pukhov and S.~Shichanin \cite{AIHENP2}.

In 1992 Andrei Davydychev  proposed to use the t'Hooft-Feynman
gauge for evaluation of squared  diagrams. This idea was
realized by A.~Pukhov.
 It has opened the real possibility 
to  calculate any 2~\verb|->|~4 process with the help of the \CompHEP~
package. In the same  year V.~Ilyin and S.~Shichanin designed
a \FORTRAN~ program of  phase-space integration  for  2~\verb|->|~3
processes
and A.~Pukhov developed the numerical interpreter for 2~\verb|->|~2 
processes. These achievements were announced in \cite{AIHENP2}.

The numerical results by \CompHEP~ for a large  set of processes  were
compared  with the {\it GRACE} package \cite{nCompare}. E.~Boos,
M~.Dubinin,  V~.Ilyin and S~.Shichanin  performed  some other cross-checks
of  the \CompHEP~ package.  Later on   A.~Belyaev, E.~Boos and L.~Dudko 
compared \CompHEP~  with the FNAL program
{\it VECBOS} \cite{Vecbos}  and
extensive cross-checks of numerical results for $e^+,e^- \to 4\quad fermions$
set of processes have been performed by M.~Dubinin \cite{YellowPreprint}.  


In 1993 the symbolic part of \CompHEP~ was rewritten in the 
{\cal C}  programming language by V.~Edneral \cite{PtoC}.
 The realization 
of the {\it Turbo Pascal} graphic routines by means of X11 tools
was done by Andrey Semenov \cite{X11}. 
It has opened  the way to create the version for  UNIX 
workstations  \cite{PtoC, AIHENP3, Seoul}.
 

   The main problem remaining in this version 
was the  phase-space  integration. \CompHEP~  created 
the \FORTRAN~ code for  squared matrix elements  with a high 
level of  automation. Generally  the matrix elements have a lot 
of singularities caused by the propagators of virtual particles.
   In order to succeed in  the Monte Carlo  phase-space
integration of singular matrix elements the user was forced every time to
modify the program of  phase-space parameterization.  

For  automation of this operation step   A.~Pukhov proposed
a general approach to the  generation  of  multi-particle kinematics
and to the regularization of  matrix elements. In 1995-96  this scheme 
was realized by A.~Pukhov, Dmitri Kovalenko and V.~Ilyin \cite{AIHENP4,
AIHENP5, kinemat}. At the same time V.~Ilyin  wrote  new 
\FORTRAN~ interface
programs like  {\it menus} and together with  A.~Kryukov
  embedded the parton structure functions
in \CompHEP. Later on the structure-function package was improved  by
A.~Pukhov to include the regularization of integration over   Feynman
parameters. As a result   we get a version which 
provides the user with a possibility   of automatic evaluation  starting from 
the input of Lagrangian  and finishing with distributions in 
physical parameters.  The corresponding service for a histogram filling
also was done by A.~Pukhov. The list of needed distributions 
was compiled by E.~Boos.

During this work it was realized that  the \Fortran~ programming 
language is not convenient for  the future development of the numerical
part of \CompHEP.   In 1997 the \C~ code output for the numerical
calculation
was designed and  the \Fortran~ program for the numerical evaluation
was rewritten in \C~ as well. This work was done by A.~Pukhov. 
In the same year A.~Kryukov  imported  \CompHEP~ onto  the MS-Windows95/NT
platform.

The development of \CompHEP~ was being under a continuous 
pressure of physicists' requests. 
The works  of  E.~Boos, 
M.~Dubinin, V.~Ilyin, V.~Savrin and S.~Shichanin, who first used  \CompHEP~
for physical calculations, at the same time
were defining a direction of the package development. They
also contribute to  and  are responsible for debugging the package.

 It must be especially  noted the role of E.~Boos and V.~Ilyin 
in  the popularization of  \CompHEP~  for  the scientific community.

The manual was written by A.~Pukhov, V.~Savrin, and S.~Shichanin.
