[petsc-users] local row calculation in 3D

[ilyas ilyas]

Hi,
Thank you for your suggestion. I will take it into account.
Since changing this structure in my "massive" code may take  too much time,
I would like to know that how "row" is calculated in 3D, independently from
processor numbers.

Regards,
Ilyas

2011/4/18 Matthew Knepley <knepley at gmail.com>

> On Mon, Apr 18, 2011 at 8:34 AM, ilyas ilyas <ilyascfd at gmail.com> wrote:
>
>> Hi,
>>
>> In ex14f.F in KSP, "row" variable is calculated either
>>
>
> These are very old. I suggest you use the FormFunctionLocal() approach in
> ex5f.F which
> does not calculate global row numbers when using a DA.
>
>    Matt
>
>
>> 349: do 30 j=ys,ys+ym-1
>> 350: ...
>> 351: do 40 i=xs,xs+xm-1
>> 352:          row = i - gxs + (j - gys)*gxm + 1
>>
>> or
>>
>> 442: do 50 j=ys,ys+ym-1
>> 443: ...
>> 444: row = (j - gys)*gxm + xs - gxs
>> 445: do 60 i=xs,xs+xm-1
>> 446:          row = row + 1
>>
>> How can I calculate "row" in 3D ?
>>
>> I tried this;
>>
>> do k=zs,zs+zm-1
>>    do j=ys,ys+ym-1
>>       do i=xs,xs+xm-1
>>
>>            row = i - gxs + (j - gys)*gxm + (k - gzs)*gxm*gym + 1
>>
>> It does not work for certain number of processors.
>>
>>
>> Thanks,
>>
>> Ilyas
>>
>
>
>
> --
> 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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