Recently, Rerát and Kirtman independently published a derivation of the PBC magnetic dipole, along with some proof of concept calculations of the β tensor . As Rerát and Kirtman note, ensuring that β has all real elements is equivalent to the constraint that m is Hermitian. However, the second term in Eq. 23 is anti-Hermitian and the third term in non-Hermitian. To ensure that the OR tensor is real, we explicitly symmetrize the magnetic dipole matrix. In practice, we only need to symmetrize the third term of Eq. 23, as the first term is already Hermitian and the second term, being anti-Hermitian, is canceled out by the symmetrization.