Improving the performance of PME or FMM, and adopting them to new GPU architectures are still being developed . Yet, it also helps to search for new methods that potentially achieve O(N) scaling without expensive prefactor calculation. To this end, a spherical grid and treecode (SGT) algorithm has been developed . It divides the long-range electrostatic interaction term into a sum involving the Gauss-Hermite quadrature and the spherical t-design , together forming a cubature. This is combined with dividing the simulation box into bisecting trees. For each "leaf" at a given level of a tree, the structure factor is calculated, which is the sum of complex exponentials involving the roots and weights of the Gauss-Hermite quadrature, and a dot product between the unit node vectors of the spherical t-design and position vectors of individual atoms within the leaf. The Coulomb potential energy and force between a given atom and atoms in a distant leaf is then simply a dot product between a cubature factor for that atom and the structure factor for the leaf, obviating the need for pairwise evaluation of interactions. Through the treecode architecture, leaves further away from the atom under consideration are grouped in increasing powers of 2 and treated as a single bigger leaf at the next level of the tree .