[AG-TECH] Access Grid Seminar

Lee Margetts Lee.Margetts at manchester.ac.uk
Mon Oct 2 14:15:05 CDT 2006

*** Apologies for Cross Posting ***


"Two recent examples of HPC Research at Manchester Computing: Symmetric Pivoting
in ScaLAPACK and Improving Collective Calls with MPI One-sided Communication"

Dr Craig Lucas & Kevin Roy, University of Manchester

Friday 6th October 2006, 1400-1500 (1300-1400 UTC)

Room 1.10, Kilburn Building

The role of the HPC team at Manchester Computing is to help support research
using HPC systems; this is achieved in many ways. This seminar provides two
recent examples of where work undertaken at Manchester Computing aids research
across scientific domains.

In the ScaLAPACK parallel numerical linear algebra library there is no symmetric
(or "complete") pivoting in its algorithms. Here we examine an implementation
of the pivoted Cholesky factorization of semidefinite matrices, which uses
symmetric pivoting, and provides new functionality for ScaLAPACK. The routine
is built using PBLAS, the BLACS routines and block cyclic data distribution.

The majority of parallel applications on HPC machines use MPI. In some cases MPI
collective operations consume a substantial amount of time reducing the
efficiency of the application. This talk describes work that has dramatically
improved the efficiency of the collective operations and hence scalability of
the applications that use them.

*** Access Grid Information ***

For information regarding joining the seminar using the Access Grid, please see

Best regards



Dr Lee Margetts
Senior HPC Consultant
University of Manchester

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