gfortran IRC meeting?

[Paul Richard Thomas]

On Fri, Mar 25, 2011 at 1:57 PM, Tobias Burnus <burnus@net-b.de> wrote:
> Paul Richard Thomas wrote:
>>
>> I thought that you might take that view of array descriptors, Tobias
>> :-)  We will have to discuss how to do it; the stumbling block for me
>> is the dimension triplet.  The rest is even easy but tedious.
>
> What's actually the issue about the dimension triplet? Which information to
> include? The performance?

>
> CFI_index_t lower_bound; equal to the value of the lower bound of an array
> for a specified dimension.
> CFI_index_t extent; equal to the number of elements of an array along a
> specified dimension.
> CFI_index_t sm; equal to the memory stride for a dimension. The value is the
> distance in bytes between the beginnings of successive elements of the array
> along a specified dimension.

This is what is already implemented in fortran-dev.  The stumbling
block is to make it work!  It is a while since I looked at it but
there were quite a few regressions.  I determined that quite a lot of
work is required get rid of all the regressions; especially in the
library.  In the end, I am not entirely convinced that there will be
any benefit in terms of performance, so the task seems like a lot of
pain for little outcome.  For that reason, I want to share the load
and this is what I want to discuss.

BTW implementing the TR is easy - remember that one of the fields in
the TR descriptor is a pointer to the internal representation, which
could be as at present.

Cheers

Paul


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