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Publications of SPCL
|T. Hoefler, R. Janisch, W. Rehm:|
|Parallel scaling of Teter's minimization for Ab Initio calculations|
(Vol , Nr. , In , presented in Tampa, FL, USA, pages , , ISSN: , ISBN: , Nov. 2006, Presented at the workshop HPC Nano in conjunction with the IEEE international conference on Supercomputing (SC'06) )
AbstractWe propose a parallelization scheme for the conjugate gradient method by Teter et. al. and report a detailed analysis of its scalability. We use MPI collective operations exclusively to take advantage of optimized collective implementations with possible hardware support. Our parallel conjugate gradient calculation can be applied in addition to the already implemented parallelism in the application ABINIT. We propose distribution schemes for the band vectors and the 3D-FFT, and provide both a detailed runtime and scalability analysis and a model for the used collective operations. We use this model of collective communication to predict the parallel scaling and to show that the scalability is mostly limited by the communication. Our codes scales up to 52 processors for a small 43 atom system and up to 120 processors for a larger 86 atom system for a single k-point on our test cluster. Our results suggest that non-blocking collective communication could be used to enhace the application running time especially for cluster computers.