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Rolf September 13, 2002 05:23

F90 Performance, Pointer
 
Hey everybody, I'm currently porting a pure F77 code to F90 by using derived data types, pointers and all that modern stuff. Unfortunately, I do loose significantly performance on nearly all platforms (HP;SGI;DEC;IBM) eventhough I do not use the pointers within computationally intensive subroutines. In those routines the data is seen as pure arrays. Using the pointer data directly in strong do-loops (something I really would like to do) kills the perfomance completely. Does somebody experience something similar in the past and does somebody now about Compiler Options which might help? I'm pretty much convinced that aliasing is the problem I'm struggling with.

Thanks in advance -Rolf

Markus Lummer September 13, 2002 05:45

Re: F90 Performance, Pointer
 
Hi Rolf,

once I have encountered a similar drop in performance using F90 pointers. I my case, the compiler obviously generated local (hidden) copies of the fields before they were passed to the subroutine. Unfortunately I have found no remedy for it.

Best regards

Markus


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