I hope other users will forgive the newbie question, but I want to get a class to use just the public domain (PD) utilities to define variable size vectors and matrices. Am I right in thinking that to stay with the PD rights I have to use NRVec and NRMat, whereas to use Vec_I_DP and Mat_O_DP etc. I would need to have the full license for all the students?

Everything in Appendix B of the Numerical Recipes in C++ is in the public domain. This includes both nrtypes.h and nrutil.h. So you can use both NRVec and Vec_I_DP freely.

Saul Teukolsky