Frequency-domain Acoustic Wave Modeling Using a Hybrid Direct-iterative Solver Based on a Domain Decomposition Method

Designing an efficient modeling tool is a key point for large 3D frequency-domain full-waveform inversion problems. We present a frequency-domain acoustic wave modeling using a hybrid direct-iterative solver based on a parallel domain decomposition method and Schur complement approach. The main interest of mixing solvers is to overcome the huge memory complexity of direct solvers while partially preserving efficient multi-RHS simulations and mitigating the iteration count in iterative solvers. To improve the convergence rate of the iterative solver, a preconditioning based on an additive Schwartz approach is used. Discretization of the Helmholtz equation is based on a parsimonious finite-difference method but the domain decomposition method could apply to any numerical scheme such as finite-element or finite-volume methods and to any media such as elastic, anisotropic ones ... To asses the efficiency of the hybrid approach, we computed simulations in the 2D Marmousi II and 3D SEG/EAGE Overthrust model, and compared results with that of a direct solver.