How to Install HepLib

• Download and extract the all-in-one archive

  wget https://heplib.github.io/download/Install.tar.gz
  tar xfv Install.tar.gz
  

• Install using install.sh

  cd Install
  INSTALL_PATH=<Path to Install> jn=8 ./install.sh
  # INSTALL_PATH=<Path to Install> jn=8 ./install-M1.sh # Apple Silicon Chip
  

Try a simple example

1. Prepare a C++ file named trace.cpp with the following content

   #include "HepLib.h"
   using namespace HepLib;
   int main(int argc, char** argv) {
    Index mu("mu"), nu("nu");
    Vector p1("p1"), p2("p2");
    Symbol m("m");
    //note GAS(1) in gline, corresponds to the identity matrix
    ex gline = GAS(p1)*GAS(mu)*(GAS(p2)+m*GAS(1))*GAS(mu);
    ex trace = form(TR(gline));
    cout << trace << endl;
    return 0;
   }
   

2. Compile trace.cpp using heplib++ from HepLib

   INSTALL_PATH/bin/heplib++ -o trace trace.cpp
   

3. Run trace to get the trace for $Tr[\gamma \cdot p_1{\gamma }^{\mu }(\gamma \cdot p_2+m\left){\gamma }_{\mu }\right]$

   ./trace
   # -4*d*p2.p1+8*p2.p1