====== CompHEP installation ======

This is a short guide for CompHEP 4.6. The complete instructions are in the [[https://gitverse.ru/comphep/comphep/content/master/INSTALL|INSTALL]] file. To install an older version, follow the INSTALL file in its archive.

===== Requirements =====

  * Linux. CompHEP also builds on macOS (see [[new-mac|macOS notes]]) and other UNIX-like systems.
  * gcc, g++, gfortran, GNU make, X11 development libraries (libX11, libXext), perl.
  * Optional: LHAPDF 6 with yaml-cpp, ROOT, libxml2 (for HepML), pdflatex (for diagram export).

Debian/Ubuntu:<code>
apt install gcc g++ gfortran make libx11-dev libxext-dev perl
</code>
Fedora/RHEL:<code>
dnf install gcc gcc-c++ gcc-gfortran make libX11-devel perl
</code>

===== Getting the code =====

Take an archive from the [[https://gitverse.ru/comphep/comphep/releases|releases page]], or clone the repository:<code>
git clone https://gitverse.ru/comphep/comphep.git
</code>

===== Building from source =====

<code>
./configure --optimise -mp
make
</code>

  * ''-mp'' enables parallel compilation with all CPU cores; ''-mpN'' uses N threads.
  * LHAPDF 6, ROOT and libxml2 are detected automatically if ''lhapdf-config'', ''root-config'' and ''xml2-config'' are in PATH. Use ''%%--with-lhapdf%%'', ''%%--no-lhapdf%%'', ''%%--with-root%%'', ''%%--no-root%%'', ''%%--with-libxml%%'' and ''%%--no-libxml%%'' to change this.
  * ''./configure %%--help%%'' lists all options.

When you update the sources, rebuild from a clean tree: ''make clean && make''.

===== Setting up a user directory =====

<code>
make setup WDIR=$HOME/comphep_work
cd $HOME/comphep_work && ./comphep
</code>

===== Testing =====

<code>
make test        # fast: numerical protocol and unit tests
make test-full   # all suites; some of them need Docker or Podman
</code>

===== Spack and Docker =====

Spack:<code>
git clone https://gitverse.ru/comphep/comphep.git
spack repo add comphep/spack
spack install comphep +lhapdf
</code>

Docker, from the source directory:<code>
docker build -f docker/Dockerfile -t comphep-build .
docker run -it comphep-build
</code>

===== Parton distributions =====

To use LHAPDF 6, install at least one PDF set, for example ''lhapdf install cteq6l1''. See the [[https://gitverse.ru/comphep/comphep/content/master/doc/LHAPDF6-migration.txt|LHAPDF 6 guide]].

===== Incompatibilities with old versions =====

  - Models of CompHEP version 4.4 and later have different notations for leptons: <code>
e,E/ne,Ne instead of e1,E1/n1,N1; m,M/nm,Nm instead of e2,E2/n2,N2; and l,L/nl,Nl instead of e3,E3/n3,N3.
</code>
  - In debug mode the environment variable COMPHEP defined in the startup scripts like ~/.cshrc can interfere with the run time environment defined in the script 'comphep'