MODFLOW 6 is parallelized using the Message Passing Interface (MPI) and the Portable, Extensible Toolkit for Scientific Computation (PETSc). This HOWTO explains how to compile these dependencies and MODFLOW 6 on Slackware.

# switch to root
su -
 
# install openmpi and python3-numpy; petsc requires python3-numpy and blas;
# build queuefiles, not packages, to automatically build any other dependencies
sbopkg -k -i "openmpi python3-numpy blas lapack"
 
# download and unzip a petsc build script
cd /tmp
wget https://clawiki.isnew.info/_media/howtos/petsc.zip
unzip petsc.zip
cd petsc
 
# build petsc
./petsc.SlackBuild
 
# install petsc
cd ..