Affiliations: Lawrence Livermore National Laboratory, PO Box 808,
L-312, Livermore, CA 94551, USA. Tel.: +1 925 423 2612; Fax: +1 925 422 3134;
E-mail: [email protected] | Jet Propulsion Laboratory, CA, USA
Note: [] Corresponding author
Abstract: The objective of our investigation is to establish robust inverse
algorithms to convert GRACE gravity and ICESat altimetry mission data into
global current and past surface mass variations. To assess separation of global
sources of change and to evaluate spatio-temporal resolution and accuracy
statistically from full posterior covariance matrices, a high performance
version of a global simultaneous grid inverse algorithm is essential. One means
to accomplish this is to implement a general, well-optimized, parallel global
model on massively parallel supercomputers. In our present work, an efficient
parallel version of a global inverse program has been implemented on the Origin
2000 using the OpenMP programming model. In this paper, porting a sequential
global code to a shared-memory computing system is discussed; several efficient
strategies to optimize the code are reported; well-optimized scientific
libraries are used; detailed parallel implementation of the global model is
reported; performance data of the code are analyzed. Scaling performance on a
shared-memory system is also discussed. The parallel version software gives
good speedup and dramatically reduces total data processing time.
Keywords: OpenMP, inverse model, least squares, GRACE, gravity
