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All three phases of the project have been completed successfully,
based on Castep 4.2 source code, though there remains some scope for
optimisation and several possible extensions. Basic Castep
calculations can be parallelised over bands in addition to the usual
parallelisation schemes, and the large matrix diagonalisation and
inversion operations have also been parallelised. Two band-independent
optimisation schemes have been implemented and shown to work under
certain conditions, but unfortunately neither is fast or robust enough
to be useful to a general Castep user, and neither have been
parallelised fully.
Despite the lack of an effective band-independent optimiser, the
performance of Castep on HECToR has been improved dramatically by this
dCSE project. One example is the standard benchmark al3x3,
which now scales effectively to almost four times the number of cores
compared to the ordinary Castep 4.2 (see figure 1.1).
Figure 1.1:
Graph showing the performance and scaling improvement
achieved by this dCSE project (using 8-way band-parallelism) compared
to the ordinary Castep 4.2 code for the standard al3x3
benchmark.
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The changes made in this dCSE project are expected to be merged into
the main Castep source code for version 4.4, due for release in the
latter quarter of 2008. It is hoped that many of the restrictions of
the new scheme will be lifted in time for Castep 4.5.
Next: Castep
Up: Introduction
Previous: The dCSE Project
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Sarfraz A Nadeem
2008-09-01