Re: [boost] Geometry and spatial indexes, my opinion

Isn't the cross product 3D-only?

The 3-dimensional cross product can be extended to n-dimensions. The n-dimensional cross-product takes (n-1) n-vectors as arguments and returns an n-vector. If the argument vectors are linearly dependent, then the return vector is 0. If the argument vectors are linearly independent, then the return vector is the unique n-vector such that 1. it is perpendicular to all the argument vectors 2. its length is equal the (n-1)-dimensional volume of the parallellepiped spanned by the argument vectors 3. the argument vectors and the return vector form a positively oriented system. --Johan