[petsc-users] local row calculation in 3D

[ilyas ilyas]

Hi Randy,

Thank you for your answer.

I have already done it. You can see it in my first e-mail.

It does not work properly for all number of processors.
For certain number of processors, it works correctly,
not for all number of processors.
For example, for 1,2,or 3 processors, it's ok.
For 4 processors, it gives wrong location, so on.
"Problem" occurs in 3rd dimension ( (kk-gzs)*gxm*gym )

Here is another suggestion (I have not tried yet) ;

       do kk=zs,zs+zm-1
        do jj=ys,ys+ym-1
          do ii=xs,xs+xm-1

            row=ii-gxs + (jj-gys)*MX + (kk-gzs)*MX*MY

MX,MY,MZ are global dimensions.This is also what I do serially

Do you think that it is correct or any other suggestions?

Regards,
Ilyas.

2011/4/18 Randall Mackie <rlmackie862 at gmail.com>

> Here's how I do it:
>
>        do kk=zs,zs+zm-1
>         do jj=ys,ys+ym-1
>           do ii=xs,xs+xm-1
>
>              row=ii-gxs + (jj-gys)*gxm + (kk-gzs)*gxm*gym
>
>
> Good luck,
>
> Randy M.
>
>
>
> On Mon, Apr 18, 2011 at 6:54 AM, ilyas ilyas <ilyascfd at gmail.com> wrote:
>
>> 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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