A nodal discontinuous Galerkin method for reverse-time migration on GPU clusters

Axel Modave, Amik St-Cyr, Wim Mulder and 
Tim Warburton
november, 2015
Publication type:
Paper in peer-reviewed journals
Geophysical Journal International, vol. 203 (2), pp. 1419 - 1435
Oxford University Press (OUP)
assets/images/icons/icon_arxiv.png 1506.00907
Improving both accuracy and computational performance of numerical tools is a major challenge for seismic imaging and generally requires specialized implementations to make full use of modern parallel architectures. We present a computational strategy for reverse-time migration (RTM) with accelerator-aided clusters. A new imaging condition computed from the pressure and velocity fields is introduced. The model solver is based on a high-order discontinuous Galerkin time-domain (DGTD) method for the pressure–velocity system with unstructured meshes and multirate local time stepping. We adopted the MPI+X approach for distributed programming where X is a threaded programming model. In this work we chose OCCA, a unified framework that makes use of major multithreading languages (e.g. CUDA and OpenCL) and offers the flexibility to run on several hardware architectures. DGTD schemes are suitable for efficient computations with accelerators thanks to localized element-to-element coupling and the dense algebraic operations required for each element. Moreover, compared to high-order finite-difference schemes, the thin halo inherent to DGTD method reduces the amount of data to be exchanged between MPI processes and storage requirements for RTM procedures. The amount of data to be recorded during simulation is reduced by storing only boundary values in memory rather than on disk and recreating the forward wavefields. Computational results are presented that indicate that these methods are strong scalable up to at least 32 GPUs for a three-dimensional RTM case.
    author={Axel Modave and Amik St-Cyr and Wim Mulder and Tim Warburton },
    title={A nodal discontinuous Galerkin method for reverse-time 
           migration on GPU clusters },
    doi={10.1093/gji/ggv380 },
    journal={Geophysical Journal International },
    year={2015 },
    volume={203 (2) },