My work requires us to have full-disk encryption, so these are the steps I use.
The basic idea is to create a LUKS-encrypted partition which is used as an LVM Physical Volume.
The GRUB boot partition isn't encrypted, but everything else is.
These steps tested and working on 22.04 (jammy) and 20.04 (focal).
There are two schools how to write numerical code, which in this document we will call the IEEE school and the Fortran school.
One end of the spectrum: no changes in floating point by the compiler, the developer must express exact intent. This is the IEEE school.
On the other end of the spectrum: Developer specifies math, the compiler is