Three-dimensional visco-acoustic modeling using a renormalized integral equation iterative solver

We present a frequency-domain renormalized integral equation formulation for solving a three-dimensional visco-acoustic medium using an iterative solver. Upon applying this special renormalization, the resulting integral equation operator can be proven to have a contraction property. Hence, solving the linear-system of equations using a Krylov optimization method, will result in a good convergence rate. Furthermore since the matrix-vector multiplication can be done using a Fast-Fourier transform (FFT) technique, its operation is of the order of ONlogN, where N is the size of the discretization grid. This technique also allows us to use matrix-free implementation. Hence, the memory usage is about ON. Numerical tests show that the computational time and memory usage of this renormalized integral equation approach can be quite competitive with the frequency-domain finite difference iterative solver. Further, the numerical examples demonstrate that it is possible to solve a problem with over 100 million unknowns using an integral equation approach.