PPT Slide

2. From VPP Fortran to HPF/JA

Since last June, we have had the opportunity to use HPF/JA with a

vector-parallel type supercomputer, Fujitsu VPP5000/56 in the

Computer Center of Nagoya University.

I had the impression that we could obtain good performance by

translating the MHD codes from VPP Fortran to HPF/JA. The main points

are summarized as follows,

(1) We can use the same domain division (z-direction in 3-dimension)

as in VPP Fortran, and overlap data at the boundary of distributed

data which was handled by "sleeve" in VPP Fortran can be replaced

by "shadow" and "reflect" in HPF/JA.

(2) Parallelizing formalities for division are performed by

"independent" sentence as is done in VPP Fortran.

(3) Lump transmission of distributed data is done by "asynchronous"

sentence.

(4) "asynchronous" sentence can be used for lump transmission between

the distributed data with different divided directions.

(5) Unnecessary communication, which was problem in HPF, can be removed

by instructions of "independent new( )" and "on home local( )".

(6) Maximum and minimum can be calculated in parallel by "reduction".