“…These methods were primarily developed to expedite the matrix-vector multiplications during the iterative solution of the VIE system. They leverage analytic or algebraic compression techniques, including the fast multipole method (FMM) [4], [5], fast Fourier transform [6]- [8], [13], low-rank compression [9], hierarchical matrices as kernel-free FMM [10], [11], and, more recently, tensor decompositions [12]. Despite the success of these methods in expediting matrixvector multiplications during iterative solution, the discretized VIE systems are often ill-conditioned.…”