INSTALL

We explain the procedure for a Linux C-shell, considering EPOS version 4.0.0 (to have a concrete case). After downloading the code, a couple of environment variables have to be defined, before compiling the code using CMake.

Download code

First, check on "Version" which versions are available and download the appropriate one.

Define environment variables

Define environment variables concerning the EPOS version number (EPOVSN), the place where the tar file has been placed (MYDIR), and based on that the name of the EPOS directory (EPO):

    setenv  EPOVSN  4.0.0  
    setenv  MYDIR  $PWD/  
    setenv  EPO  ${MYDIR}epos${EPOVSN}/  

Then one defines the place where intermediate files and executables should be placed (LIBDIR), and the directories for input (OPT), histogram output (HTO) and other kinds of output like run information and checks (CHK), like

    setenv LIBDIR ${EPO}bin  
    setenv OPT ./  
    setenv HTO ./  
    setenv CHK ./  

There are two compilation modes, the DEMO mode which allows simple applications and does not depend on external libraries, and the BASIC mode which allows standard EPOS applications, requiring the installation of ROOT and FASTJET. The mode needs to be defined via the variable COP. We will discuss the two options below.

Source file installation

    cd $MYDIR  
    tar xvfz epos${EPOVSN}.tgz  

Compilation and test, DEMO mode

    setenv COP DEMO  
    cd $EPO  
    rm -Rf $LIBDIR && cmake3 -B$LIBDIR && make -C$LIBDIR -j8  
    cd examples/  
    $EPO/scripts/epos expl1   

This will run EPOS taking input from expl1.optns. Output will be in z-expl1.histo and z-expl1.check, as explained via comments in the optns file. In the same way, one may use expl2, expl3, or expl4.

The latter one represents proton-proton scattering using the PFE option (parameterized fluid expansion), which allows fast simulations including collective effects, via fluid expansion and hadronic cascade. Most results are very similar to the (much slower) full simulation, so it may be useful for tests.

Compilation and test, BASIC mode

Here one first needs to install ROOT and FASTJET and define the two environment variables ROOTSYS and FASTSYS pointing to the corresponding directories, and put $ROOTSYS/bin and $FASTSYS/bin into the path, with something like

    set path= ( $ROOTSYS/bin $FASTSYS/bin $path )

and then

    setenv COP BASIC  
    setenv LD_LIBRARY_PATH $ROOTSYS/lib:$ROOTSYS/lib/root:/usr/local/lib  
    cd $EPO  
    rm -Rf $LIBDIR && cmake3 -B$LIBDIR && make -C$LIBDIR -j8  
    cd examples/  
    $EPO/scripts/epos expl5  

In the same way, one may use expl1, expl2, expl3, expl4, or expl6.

The $EPO/scripts/epos script uses a fixed seed for the random number initialization, so running the code several times will produce identical results. To change this, one may replace "seedj=111111111" and "seedi=222222222" in the script by

    seedj=`date  '+%N'`  
    seedi=`date  '+%N'`  

which allows making parallel runs to increase statistics.