Code verification for practically singular equations

The method-of-moments implementation of the electric-field integral equation (EFIE) yields many code-verification challenges due to various sources numerical error and their possible interactions. Matters are further complicated by singular integrals, which arise from presence a Green's function. To address these an approach was previously presented wherein both solution function manufactured. Because arising equations poorly conditioned, they reformulated as set constraints for optimization problem that selects closest manufactured solution. In this paper, we demonstrate how, such practically systems equations, computing truncation inserting exact into discretized cannot detect certain orders coding errors. On other hand, discretization optimal is more sensitive metric can less than those expected convergence rate.