Spectral Element Method and GPU Computing for Seismic Imaging
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Spectral Element Method and GPU Computing for Seismic Imaging Chaiwoot Boonyasiriwat May 1, 2010
description
Spectral Element Method and GPU Computing for Seismic Imaging. Chaiwoot Boonyasiriwat May 1, 2010. Outline. Introduction to Seismic Imaging Spectral Element Method GPU Computing and Computational Steering Summary. 1. Seismic Imaging. Given a seismic data set. - PowerPoint PPT Presentation
Transcript of Spectral Element Method and GPU Computing for Seismic Imaging
Spectral Element Method andGPU Computing for Seismic Imaging
Chaiwoot BoonyasiriwatMay 1, 2010
Outline
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• Introduction to Seismic Imaging• Spectral Element Method• GPU Computing and Computational Steering• Summary
Seismic Imaging
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• Given a seismic data set )( trueobs A md
• Find a model that best describes the given data or minimizes the misfit function where
)(~ trialcalc A md 2
)()( mddm calcobsE
m?CSG
Common shot gather
Seismic Imaging
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obsd
m?
• Use iterative gradient-based methods
Seismic Imaging in 3D
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• Improve efficiency• Forward modeling: use better numerical methods• Improve convergence rate: preconditioning• Use many sources simultaneously
Forward Modeling
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• Important component of seismic imaging methods)(md A
• Numerically solving a wave equation, e.g., acoustic wave equation
spvptt 22
• Numerical methods:• Finite difference• Spectral/pseudo-spectral• Finite element/spectral element
Outline
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• Introduction to Seismic Imaging• Spectral Element Method• GPU Computing and Computational Steering• Summary
Finite Element Methods
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FDM vs FEM
Finite Element Formulation
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Acoustic wave equation),(),()(),( 22 tstpvtptt rrrr
rrr vsdpdvvvpdtt2 Weak form
n
iii tPtp
1
)()(),( rr Linear combination of basis functions
FKPPM tt
rM dM jiijij ][
rK dvK jiijij 2][
where
Matrix form
rdspvpv tt22 Weighted residual method
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Geophysical Applications of FEM
• Global-scale• Exploration-scale
Outline
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• Introduction to Seismic Imaging• Spectral Element Method• GPU Computing and Computational Steering• Summary
Seismic Imaging on GPUs
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• High performance and large band-width• General-purpose computing on GPUs using CUDA• Advanced hardware (GPUs) + algorithm
(multisource imaging)• Computational steering: computation + visualization
13Courtesy of NVIDIA
1000
Peak
GFL
OP/
s 750
500
250
0
Performance of GPU vs CPU
Memory Bandwidth of GPU vs CPU
14Courtesy of NVIDIA
120
BandwidthGB/s
100
80
60
40
20
0
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Conventional vs Multisource Method
Conventional RTM Image using 200 gathers
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Multisource RTM Image using 20 supergathers
10x speedup
Conventional vs Multisource Method
Computational Steering
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• Initial model• Line search method• Regularization• Iteration number• Perturb model
manually (steering)
User Interface
Iteration numberM
isfit
val
ue
True model
Tomogram 1
Tomogram 218
Summary
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• Seismic imaging using spectral element methods• Global-scale waveform inversion using SEM• 3D seismic imaging on GPU cluster (CUDA+MPI)• Computational steering on GPU cluster
