Function c = dot3d(a,b) returns the dot product of two 3-dimensional vectors a and b. Matrices a and b have 3 columns which contain the x,y,z coordinates, respectively. The operation is done per corresponding row in a and b. The validity of the input is not checked! (c) 2026 fabien van mook 2026.08.20 release of this file within package "fvm-geometry" under GNU GPLv3+