This is a first suggestion of how to implement spatio-temporal vector
fields. It is hardly tested and more a foundation for a discussion.

The normalisation in the projector has to use the first `vec_dim`
elements of the cov_samples, just check div. of equations.

This is a first suggestion of how to implement spatio-temporal vector
fields. It is hardly tested and more a foundation for a discussion.

The normalisation in the projector has to use the first `vec_dim`
elements of the cov_samples, just check div. of equations.

…nto nd-vector-fields