Christina DWI Riyanti

Postdoctoral Fellow

Scientific Computing
Delft Institute of Applied Mathematics (DIAM)
  Delft University of Technology (TUDELFT)

Mekelweg 4, 2628 CD Delft
The Netherlands
Office: +31-15-2787297
Hp: +31-61-4267181
c.d.riyanti<at>ewi.tudelft.nl
Project: "Rigorous modeling of 3D wave propagation in inhomogeneous media for geophysical and optical problems"

The objective of this research is to develop a parallel performance of an iterative solver for 3D heterogeneous Helmoltz problems related to applications in seismic wave propagation. The algorithm is based on a finite difference method. We solve the linear system by using a Krylov subspace method (preconditioned BiCGSTAB) combined with the multigrid method. A complex-shifted Laplacian is used as the preconditioner and the multigrid method is employed to approximate the inverse of the preconditioner. The method can also be applied to optical problems. For large 3D problems, the computation is no longer feasible on a single processors, and the memory requirements increase rapidly. Therefore, parallelization of the solver is needed. Large 3D models arising in the geophysical applications for high frequency are computed using this method. This method can also serve as a starting point for solving the full inverse problem and to develop an imaging technique based on the finite-difference wave-equation in the frequency domain.


This work is part of a joint project between Philips and Shell and this project was financially supported by the Dutch Ministry of Economic Affairs.


Methods:

- Finite difference method
- Krylov subspace iterative method
- Multigrid method
- Parallel computing


Programming skills:

- Fortran 77 and 90
- C/C++
- Matlab, Maple, Seismic Unix
- Parallel Implementation (MPI, Open MP)
- Linux/Unix, Windows