Start julia from main directory with julia --project
then compute the energy like
using Distributed
addprocs(exeflags="--project=@.") # these two lines enable MC sampling on all cores
using VITA2D
energy(L=4, P=1, θ=ones(3), Nmc=10^4, hX=3.0)
If it doesn't run, then try
julia --project
Now press ]
and type instantiate
This should initialize the project and all dependancies.