TY  - CONF
AU  - Di Napoli, Edoardo
AU  - Berljafa, Mario
TI  - Parallel block Chebyshev subspace iteration algorithm optimized for sequences of correlated dense eigenproblems
M1  - FZJ-2012-00907
PY  - 2012
AB  - In many material science applications simulations are made of dozens of sequences, where each sequence groups together eigenproblems with increasing self-consistent cycle outer-iteration index. Successive eigenproblems in a sequence possess a high degree of correlation. In particular it has been demonstrated that eigenvectors of adjacent eigenproblems become progressively more collinear to each other as the outer-iteration index increases. This result suggests one could use eigenvectors, computed at a certain outer-iteration, as approximate solutions to improve the performance of the eigensolver at the next one. In order to opti- mally exploit the approximate solution, we developed a block iterative eigensolver augmented with a Chebyshev polynomial accelerator (BChFSI). Numerical tests show that, when the sequential version of the solver is fed approximate solutions instead of random vectors, it achieves up to a 5X speedup. Moreover the parallel shared memory implementation of the algorithm obtains a high level of efficiency up to 80 \% of the theoretical peak performance. Despite the eigenproblems in the sequence being relatively large and dense, the parallel BChFSI fed with ap- proximate solutions performs substantially better than the corresponding direct eigensolver, even for a significant portion of the sought-after spectrum
T2  - 5th International Conference of the ERCIM Working Group
CY  - 2 Dec 2012 - 2 Dec 2012, Oviedo (Spain)
Y2  - 2 Dec 2012 - 2 Dec 2012
M2  - Oviedo, Spain
LB  - PUB:(DE-HGF)6
UR  - https://juser.fz-juelich.de/record/127961
ER  -