Gravity inversion using wavelet-based compression on parallel hybrid CPU/GPU systems: application to South-West Ghana

Abstract : We solve the 3-D gravity inverse problem using a massively parallel voxel (or finite element) implementation on a hybrid multi-CPU/multi-GPU (graphics processing units/GPUs) cluster. This allows us to obtain information on density distributions in heterogeneous media with an efficient computational time. In a new software package called TOMOFAST3D, the inversion is solved with an iterative least-square or a gradient technique, which minimizes a hybrid L1-/L2-norm-based misfit function. It is drastically accelerated using either Haar or fourth-order Daubechies wavelet compression operators, which are applied to the sensitivity matrix kernels involved in the misfit minimization. The compression process behaves like a pre-conditioning of the huge linear system to be solved and a reduction of two or three orders of magnitude of the computational time can be obtained for a given number of CPU processor cores. The memory storage required is also significantly reduced by a similar factor. Finally, we show how this CPU parallel inversion code can be accelerated further by a factor between 3.5 and 10 using GPU computing. Performance levels are given for an application to Ghana, and physical information obtained after 3-D inversion using a sensitivity matrix with around 5.37 trillion elements is discussed. Using compression the whole inversion process can last from a few minutes to less than an hour for a given number of processor cores instead of tens of hours for a similar number of processor cores when compression is not used.
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Article dans une revue
Geophysical Journal International, Oxford University Press (OUP), 2013, 195 (3), pp.1594-1619. <10.1093/gji/ggt334>
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https://hal.archives-ouvertes.fr/hal-00905098
Contributeur : Dimitri Komatitsch <>
Soumis le : vendredi 15 novembre 2013 - 23:16:17
Dernière modification le : mardi 10 mai 2016 - 11:06:06

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Roland Martin, Vadim Monteiller, Dimitri Komatitsch, Stephane Perrouty, Mark Jessell, et al.. Gravity inversion using wavelet-based compression on parallel hybrid CPU/GPU systems: application to South-West Ghana. Geophysical Journal International, Oxford University Press (OUP), 2013, 195 (3), pp.1594-1619. <10.1093/gji/ggt334>. <hal-00905098>

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