Application of Hierarchical Two-Level Spectral Preconditioning Method for Electromagnetic Scattering from the Rough Surface

<table>Convergence history of the hierarchical two-level spectral preconditioned GMRES, FGMRES and GMRES algorithms for 2-order hierarchical Legendre basis functions for the missile target above a rough surface.</table>

International Journal of Antennas and Propagation

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Figure 9

Figure 9: Application of Hierarchical Two-Level Spectral Preconditioning Method for Electromagnetic Scattering from the Rough Surface 