[petsc-users] Use of DMDAVecGetArrayF90 and DMDAVecRestoreArrayF90

[TAY wee-beng]

On 10/11/2015 8:27 PM, Matthew Knepley wrote:
> On Tue, Nov 10, 2015 at 3:27 AM, TAY wee-beng <zonexo at gmail.com 
> <mailto:zonexo at gmail.com>> wrote:
>
>     Hi,
>
>     Inside my subroutine, I need to access the DA variable
>     cu_types_array frequently.
>
>     So I need to call DMDAVecGetArrayF90 and DMDAVecRestoreArrayF90
>     before and after frequently.
>
>     Is this necessary? Can I call DMDAVecGetArrayF90 at the start and
>     only call DMDAVecRestoreArrayF90 towards the end, where I don't
>     need to modify the values of cu_types_array anymore?
>
>     Will this cause memory corruption?
>
>
> You cannot use any other vector operations before you have called Restore.

Hi,

What do you mean by vector operations? I will just be doing some maths 
operation to change the values in cu_types_array. Is that fine?
>
>     Also, must the array be restored using DMDAVecRestoreArrayF90
>     before calling DMLocalToLocalBegin,DMLocalToLocalEnd?
>
>
> Yes.
>
>   Matt
>
>
>     -- 
>     Thank you.
>
>     Yours sincerely,
>
>     TAY wee-beng
>
>
>
>
> -- 
> What most experimenters take for granted before they begin their 
> experiments is infinitely more interesting than any results to which 
> their experiments lead.
> -- Norbert Wiener

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