A Linux cluster for between-pulse magnetic equilibrium reconstructions andother processor bound analyses

A 12-processor Linux PC cluster has been installed to perform between-pulse magnetic equilibrium reconstructions during tokamak operations using the E FIT code written in FORTRAN. The MPICH package implementing message passing interface is employed by EFIT for data distribution and communication. The new system calculates equilibria eight times faster than the previous syst em yielding a complete equilibrium time history on a 25 ms time scale 4 min after the pulse ends. A graphical interface is provided for users to contr ol the time resolution and the type of EFITs. The next analysis to benefit from the cluster is CERQUICK written in IDL for ion temperature profile ana lysis. The plan is to expand the cluster so that a full profile analysis (T e, Ti, ne, Vr, Zeff) can be made available between pulses, which lays the g round work for Kinetic EFIT and/or ONETWO power balance analyses. (C) 2001 American Institute of Physics.