Efficient Solution of 3-D Vector Electromagnetic Scattering by CG-MLFMA with Partly Approximate Iteration

摘要

In the conjugate gradient iteration-multilevel fast multipole algorithm (CG-MLFMA), the matrix-vector multiplication can be implemented by the interactions from nearby region and non-nearby region. Based on CG-MLFMA, an efficient partly approximate iteration technique is developed for solving the scattering from the object with large electrical sizes in this paper. When the iterative error is low than the critical iteration error (CIE), determined by the contributions of nearby region and the accuracy required, the matrix-vector multiplication can be computed approximately by the interactions from nearby region. Compared to the interactions from non-nearby region, the interactions from nearby region only possess a very small portion of total complexity. So the total CPU time can be reduced greatly, although the total number of iteration needed in the present method is nearly same to the one in CG-MLFMA. Numerical results are given to demonstrate the validity and efficiency of the present method.