Here are the instructions that work as of today [August 8th 2023 -- on Mac OS X Ventura 13.4.1 (c)].
This will currently exclude GoSam and VBFNLO.
- You need the homebrew package manager installed (https://brew.sh) with gcc (currently: 13.1.0) installed as well. This gives you gfortran 13.1.0: ```brew install gcc'''. You will need automake and python, if you don't have them installed already.
- Add this version of gfortran in the herwig-boostrap:
```if platform.system() == 'Darwin':
default_cc = os.getenv('CC', '/usr/bin/clang')
default_cxx = os.getenv('CXX', '/usr/bin/clang++')
default_fc = os.getenv('FC', '/opt/homebrew/bin/gfortran')```
- Using homebrew, “tap” into the homebrew-hep repo (see https://github.com/davidchall/homebrew-hep):
```brew tap davidchall/hep```
and install the following:
```brew install fastjet lhapdf boost hepmc3```
- Also install the LHAPDF pdfs:
```lhapdf install CT14lo; lhapdf install CT14nlo```
- Then run the bootstrap with:
./herwig-bootstrap --herwig-hg --thepeg-hg --with-boost=/opt/homebrew/Cellar/boost/1.82.0_1/ --with-fastjet=/opt/homebrew/Cellar/fastjet/3.4.0_1 --with-lhbapdf=/opt/homebrew/Cellar/lhapdf/6.5.3 --with-hepmc3=/opt/homebrew/Cellar/hepmc3/3.2.6/ --without-gosam --without-vbfnlo Herwig-full/
[versions of dependencies will change, so they will need to be adjusted accordingly -- check the versions installed in your /opt/homebrew/Cellar directory]
- Herwig will fail during the LoopTools compilation. I found that additional FCFLAGS are necessary, so I re-configure Herwig by finding the ./configure line in the Herwig-7.3.0/config.log and adding
```FCFLAGS='-w -fno-range-check -fallow-argument-mismatch -O2 -ffixed-line-length-none -DQUAD=0 -DQUADSIZE=16 -DU77EXT=0' ```
i.e. in my case, this looks like:
```./configure --prefix=/Users/apapaefs/Projects/Herwig/Herwig-full/ --with-thepeg=/Users/apapaefs/Projects/Herwig/Herwig-full/ --with-boost=/opt/homebrew/Cellar/boost/1.82.0_1/ --with-gsl=/Users/apapaefs/Projects/Herwig/Herwig-full/ --with-fastjet=/opt/homebrew/Cellar/fastjet/3.4.0_1 --with-madgraph=/Users/apapaefs/Projects/Herwig/Herwig-full/opt/MG5_aMC_v3_5_1 --with-openloops=/Users/apapaefs/Projects/Herwig/Herwig-full/opt/OpenLoops-2.1.2 --with-pythia=/Users/apapaefs/Projects/Herwig/Herwig-full/ --with-evtgen=/Users/apapaefs/Projects/Herwig/Herwig-full/ FCFLAGS='-w -fno-range-check -fallow-argument-mismatch -O2 -ffixed-line-length-none -DQUAD=0 -DQUADSIZE=16 -DU77EXT=0'```
[Again, package versions will change!]
- After re-reconfiguring Herwig, re-run the boostrap as before.