Update a subset of vectors.
The index must have a direct_map
@param nv nb of vectors to update @param idx vector indices to update, size nv @param v vectors of new values, size nv*d
See Implementation
Update a subset of vectors.
The index must have a direct_map
@param nv nb of vectors to update @param idx vector indices to update, size nv @param v vectors of new values, size nv*d