[petsc-dev] errors for /petsc/src/ts/examples/tutorials/ex29.c

Barry Smith bsmith at mcs.anl.gov
Thu Sep 22 22:19:58 CDT 2016

branch barry/fix-dmdacreate in next for testing pulls the DMSetFromOptions() and DMSetUp() call out of the DMDACreateNd(). It also removes any special handling of negative M,N, and P arguments.


> On Sep 15, 2016, at 11:35 PM, Jed Brown <jed at jedbrown.org> wrote:
> Barry Smith <bsmith at mcs.anl.gov> writes:
>>  A perhaps better fix is to finally remove this from the DMDCreateNd() calls 
>>  /* This violates the behavior for other classes, but right now users expect negative dimensions to be handled this way */
>>  ierr = DMSetFromOptions(*da);CHKERRQ(ierr);
>>  ierr = DMSetUp(*da);CHKERRQ(ierr);
>>  Perhaps we could remove both of these lines from those calls and require every use of DMDCreateNd() to add the 
>> DMSetUp() call. Then the user is free to insert a DMSetFromOptions() in between or not. We remove the negative value business which is hokey anyway?
>>  So in the use of DMDAGetReducedDMDA() it could call DMDACreate2d() then the DMSetUp() but skip the DMSetFromOptions() line.
> I won't stop you, but I'm not sure that's worth it.  We don't use
> MatCreateAIJ type "convenience" functions in library code, so why should
> we use the DMDACreate*d convenience functions?  Presumably doing so
> would remove the conditionals (over dimension) that we have now.  Or
> perhaps we should do both?

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