[petsc-users] array still valid after DMDAVecRestoreArrayF90()?

[Jed Brown]

On Sun, Jul 15, 2012 at 11:20 PM, Panruo Wu <pwu at mymail.mines.edu> wrote:

> Hello,
>
> For some reason, it would be convenient for me to do something
> like
>
> call DMDAVecGetArrayF90(da, global, array, ierr)
>
> call DMDAVecGetArrayF90(da, global, array, ierr)
> ! read-only access to array here.
> call DMDAVecRestoreArrayF90(da, global, array,ierr)
> ! read&write access to array here.
> call DMDAVecRestoreArrayF90(da, global, array, ierr)
>

No, it is not okay to lie about the array status.


>
> Will this piece of code do what I expect?  I wrote a simply
> program which gave positive answer but I want to know if
> it's guaranteed to work or only happened to be working.
>
> Thanks!
> Panruo Wu
>
> On Sat, Jul 14, 2012 at 1:30 PM, Panruo Wu <pwu at mymail.mines.edu> wrote:
>
>> Thank you Barry!
>>
>> Panruo
>>
>>
>> On Sat, Jul 7, 2012 at 3:10 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:
>>
>>>
>>>    So long as you have the same boundary types and the same array sizes
>>> in the i and j direction they give the same distribution.
>>>
>>>     Barry
>>> On Jul 7, 2012, at 3:58 PM, Panruo Wu wrote:
>>>
>>> > Hello,
>>> >
>>> > If I create 2 DAs with (almost) identical parameters except DA name
>>> > and dof like:
>>> >
>>> > call DMDACreate2d(PETSC_COMM_WORLD, DMDA_BOUNDARY_GHOSTED,
>>> > DMDA_BOUNDARY_GHOSTED, &
>>> >   stype, M, N, m, n, dof1, s &
>>> >   PETSC_NULL_INTEGER, PETSC_NULL_INTEGER, &
>>> >   da1, ierr)
>>> >
>>> >
>>> >
>>> > call DMDACreate2d(PETSC_COMM_WORLD, DMDA_BOUNDARY_GHOSTED,
>>> > DMDA_BOUNDARY_GHOSTED, &
>>> >   stype,  M, N, m, n, dof2, s &
>>> >   PETSC_NULL_INTEGER, PETSC_NULL_INTEGER, &
>>> >   da2, ierr)
>>> >
>>> >
>>> > my question is, will the two DAs have the same distribution scheme?
>>> > Specifically,
>>> > will the DMDAGetCorners() give the same results when querying da1 &
>>> da2?
>>> >
>>> > Thanks,
>>> > Panruo Wu
>>>
>>>
>>
>
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