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From: prentice@triton.unm.edu (John Prentice)
Newsgroups: comp.lang.fortran
Subject: vectorization question
Message-ID: <1991Mar29.141313.7418@ariel.unm.edu>
Date: 29 Mar 91 14:13:13 GMT
Organization: University of New Mexico, Albuquerque, NM
Lines: 38
Originator: prentice@triton.unm.edu

Consider the following loop:

      do 30 k=1,kmax
	  do 20 j=1,jmax
	      do 10 i=1,imax
		  a(i,j,k)=...
   10         continue
   20     continue
   30 continue

On the Cray, only the inner most loop will vectorize.  Does anyone
have a suggestion for how to collapse this loop while still using
the three dimensional array?  In other words, I need a vectorized
equivalent to:

      i=0
      j=1
      k=1
      do 10 n=1,imax*jmax*kmax
	  i=i+1
	  if (i.gt.imax) then
	      i=1
	      j=j+1
	      if (j.gt.jmax) then
		  j=1
		  k=k+1
              endif
          endif
	  a(i,j,k)=...
   10 continue

Any suggestions would be welcomed.  Thanks.

John
-- 
John K. Prentice    john@unmfys.unm.edu (Internet)
Dept. of Physics and Astronomy, University of New Mexico, Albuquerque, NM, USA
Computational Physics Group, Amparo Corporation, Albuquerque, NM, USA