Memory storage of multidimensional arrays in fortran 90


by vacuum
Tags: arrays, fortran, memory
vacuum
vacuum is offline
#1
Oct17-10, 08:01 AM
P: 26
Hello,

I think i heard somewhere that a multidimensional array in fortran 90 may be stored non-contiguously in memory. Is this true? Even if it the size was known at compile time?

If your answer is it depends on a compiler, what about ifort and gfortran?
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vacuum
vacuum is offline
#2
Oct19-10, 06:24 AM
P: 26
OK, after some investigation, I found that fortran 90, unlike fortran 77 (and C) does not impose a storage implementation on the arrays. But, according to some people, in all implementations at least the first index is contiguous. What is certainly not contiguous are subarrays chosen with a stride of course (A(1:50:10)), though when used as an argument they are usually copied to a contiguous temporary. The pointers to such arrays are also not contiguous.
If arrays are defined with a simple format, e.g. A(10,20,30), they are, in most (all?) cases contiguous.

Any further comments or clarifications would be welcome.


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