Equations and Python code for going back and forth between quaternion and matrix representations of rotations.| John D. Cook
There are a lot of classic Fortran libraries from the 1970s to the early 1990s whose names end in "pack" (or, more specifically, "PACK"). I presume this stands for "package", and it seems to have been a common nomenclature for software libraries back in the day. Here is a list …| Degenerate Conic