Function u = unitvector(v) returns the unit vector of the 3-dimensional input vectors. Matrices v and u have 3 columns which contain the x,y,z coordinates, respectively. Each row represents a 3-dimansional vector. The validity of the input is not checked! Nor zero vectors [0, 0, 0] are picked out! (c) 2026 fabien van mook 2026.08.20 release of this file within package "fvm-geometry" under GNU GPLv3+