A PARALLEL SPECTRAL ELEMENT METHOD FOR ACOUSTIC-WAVE MODELING

The finite element method is well reputed for its great flexibility in solving problems with complex geometries and heterogeneous structures ! but, in its classical form, it has fairly low accuracy and poor comp utational efficiency. This makes an adverse impact on a large-scale nu merical simulation of acoustic wavefield propagation. It has been show n by the author and his co-workers that the spectral approach, based o n the use of high-order orthogonal interpolating functions (the Spectr al Element Method), yields high accuracy with almost no numerical arti facts; it also significantly reduces the simulation computing costs. I n this paper, the method is presented in conjunction with an iterative solution technique in such a way that it fully exploits the currently available parallel computers. The underlying algorithm is based on th e observations that the assembly of mass and stiffness matrices is not really needed, and that the matrix-vector product required for the it erations can be done concurrently via an element-by-element approach. Moreover, by using a tenser-product sum-factorization scheme, computat ional and storage requirements can be further reduced as neither eleme nt nor global matrices are ever formed. The method is tested on the Gr ay T3D MPP computer, and its parallel efficiency and speed performance are discussed.