Fast direct solution of high-order MoM accelerated by local ACA

In this paper, the local adaptive cross approximation based on the compressed LDL
^T
factorization is proposed to directly solve the matrix equation obtained by high-order hierarchical MoM. By means of the local ACA algorithm, high accurate result with much higher compressed rate can be achieved. Because of using the hierarchical high-order basis functions (BFs), the number of the unknowns is rapidly reduced. We extensively investigate the compressed LDL
^T
factorization on the use of Local ACA algorithm, and provide remedial procedures to improve the efficiency of the implementations.