[petsc-users] updating values in a DA Global array

[Barry Smith]

On Jun 23, 2010, at 4:01 AM, Jed Brown wrote:

> On Tue, 22 Jun 2010 23:35:08 -0500, Barry Smith <bsmith at mcs.anl.gov> wrote:
>>   Looking at this more closely and trying to do it, I think it may
>>   not be possible in F90. You don't seem to be able to set the range
>>   of indices in the ptr array (it seems it must always be
>>   1:somevalue) so we can't do the trick we do in C and F77 of
>>   embedding a smaller 2d array inside an imaginary larger array and
>>   accessing values out of the smaller array by using indices of the
>>   larger array.
> 
> Is it possible to declare the bounds when you declare the pointer?

   I cannot find any F90 syntax that allows that. 

   Barry

>  Even
> if that worked, it's not clearly less awkward than using a separate
> local function, which is not completely unreasonable.  Slightly awkward
> to work with, but it does direct addressing which we can't do for
> multi-dimensional non-0-based arrays in C (C99 offers direct indexing
> for runtime-dimensioned 0-based arrays).
> 
> Jed