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[previous article]Tired of slow execution of your FORTRAN programs? Interested in giving your programs some pep? Why not experience life in the fast-lane by using the Gould Advanced Vector Preprocessor (available on the NP-1 only). The vector preprocessor is a software tool that translates DO loops and IF statements into the array syntax described in the proposed FORTRAN 8X standard. The main advantage of this array syntax is the use of vector hardware features which allow faster execution.
To demonstrate the impact of vectorization on code processing, comparison runs have been made with the DIF3D program. The DIF3D program is 96,000+ lines of sophisticated code developed at Argonne National Laboratory for nuclear reactor design. It solves the multi-group neutron diffusion equation in 1, 2 or 3 dimensions for a wide variety of geometries using standard finite-differencing or nodal techniques and uses a red/black SLOR algorithm that has been vectorized on CRAY machines with great success. The code is currently being used by Mike Orr of Nuclear Engineering to redesign the Purdue University Reactor (PUR-1) and by Chi-wen Tsaoi to analyze the Fast Breeder Blanket Facility (FBBF) in the basement of Physics.
The table below compares DIF3D being processed with different data sets on the NP-1 (vectorized and non-vectorized) and the CYBER 205. The NP-1 vector version was compiled with the -f -c -O -V options of fort. The CYBER 205 version was compiled with opt=dprs, and then processed with KAP 4.0. Looking at the table, dramatic differences are shown between vectorized and non- vectorized runs on the NP-1 with Tsaoi's runs decreasing execution time by about 3000 seconds (almost an hour) and yielding a 25-30% reduction in CPU time. Note: Tsaoi's account was charged $675.00 to run her program on the CYBER 205 and zero to run on the NP-1. Turnaround time was about 60 hours for the CYBER 205 and 18 hours for the NP-1.
Talk with your site specialist if you are interested in using the vector preprocessor on the NP-1 The manual ECN #742 Gould Advanced Vector Preprocessor User's Guide is an invaluable aid that is available in the reference section of Potter Library.
NP-1 NP-1 CYBER 205
Problem (non-vector) (vector) (vector)
Description (sec) (sec) (sec)
DIF3D 174 group 2-D Hex geo.,FBBF (Tsaoi) 10,250 7145 2802
DIF3D 2 group 3-D X-Y-Z geo., PUR-1 (Orr) 1,910 1393 128
DIF3D 4 group 3-D Hex geo., Benchmark (Rhodes)354 221 71
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