) can be a finite basis set (B i λi with nb i λi basis functions) or a finite quadrature grid (G i λi with nq i λi grid points and weights). The index, λ i , enables to control the sizes of the i th basis set and grid (see below for their relations). Tipically, nb i λi and nq i λi values are larger than 10, so that the total number of basis functions, N b or grid point N q are larger than 10 n .