[Nek5000-users] hpts and pressure

Tue Jun 14 13:27:21 CDT 2011

Josh, Stefan,

Correct... we should just add the map to the hpts
routine.   Maybe Katie can take care of this.

Thanks for raising this issue!

Paul

On Tue, 14 Jun 2011, nek5000-users at lists.mcs.anl.gov wrote:

> Hi
>
> You are right, the pressure is not mapped automatically. This issue
> was already discussed in
> https://lists.mcs.anl.gov/mailman/htdig/nek5000-users/2010-May/000584.html.
> At the moment there is only a trigger to map the pressure in case we
> are dumping a field file
>
> @Paul: I am not sure where we should trigger the pressure mapping but
> the way it's implement now is error prone.
>
> -Stefan
>
> On 6/14/11, nek5000-users at lists.mcs.anl.gov
> <nek5000-users at lists.mcs.anl.gov> wrote:
>> Hello,
>>
>> It appears my hypothesis was correct.  I post the following for
>> reference to any users who run into the same issue in the future (and
>> I apologize in advance if this question has already been answered
>> before, I didn't see anything in my search, but that doesn't mean it
>> wasn't there).
>>
>> 1)  I included the following in the variable declarations of userchk()
>>
>>       common /scrcg/ pm1(lx1,ly1,lz1,lelv)  ! Mapped pressure
>>       real pa(lx1,ly2,lz2), pb(lx1,ly1,lz2) ! Working arrays for mappr
>>
>> 2) Then, before I call hpts, I call mappr
>>
>>       if (mod(istep,10).eq.0) then   ! Only call this every 10th step
>>          call mappr(pm1,pr,pa,pb)   ! Map pressure first
>>          call hpts
>>       endif
>>
>> For my case, I didn't want to call hpts every time step to prevent
>> hpts.out from becoming too large.
>>
>> I haven't run this for too long, but on a preliminary basis the
>> results look good.  It seems that the scrcg common block must be
>> included in userchk for this to work, as pm1 isn't a part of any of
>> the standard "include" files.
>>
>> Developers and other users, feel free to chime in if there is a more
>> efficient or elegant solution to this problem.
>>
>> Thanks,
>>
>> Josh
>>
>> On Mon, Jun 13, 2011 at 6:42 PM,  <nek5000-users at lists.mcs.anl.gov> wrote:
>>> Hi Josh,
>>>
>>> Yes, it seems to me that either htps() needs modification for Pn-Pn-2
>>> pressure points or pr() should be mapped to pm1() before calling htps() as
>>> you suggested -- something along the lines for .not.ifsplit in
>>> prepot.f:219
>>>
>>>         if (ifsplit) then
>>>            call copy(pm1,pr,ntot1)
>>>         else
>>>            do 1000 e=1,nelv
>>>               call mxm (ixm21,nx1,pr(1,1,1,e),nx2,pa(1,1,1),nyz2)
>>>               do 100 iz=1,nz2
>>>                  call mxm (pa(1,1,iz),nx1,iytm21,ny2,pb(1,1,iz),ny1)
>>>  100          continue
>>>               call mxm (pb(1,1,1),nxy1,iztm21,nz2,pm1(1,1,1,e),nz1)
>>>  1000       continue
>>>         endif
>>>
>>> Best,
>>> Aleks
>>>
>>>
>>> ----- Original Message -----
>>> From: nek5000-users at lists.mcs.anl.gov
>>> To: "nek5000-users" <nek5000-users at lists.mcs.anl.gov>
>>> Sent: Monday, June 13, 2011 5:29:50 PM
>>> Subject: [Nek5000-users] hpts and pressure
>>>
>>> Hello Neks,
>>>
>>> I am trying to output pressure data at various points using the hpts
>>> routine.
>>>
>>> The values that are output for the first time step look ok, but all
>>> subsequent time steps seem to give garbage (i.e. the pressures given
>>> in hpts.out are way different that what is given by visualizing
>>> pressure in VisIt).  I know previously that this was an issue for
>>> someone and it was thought that passive scalars may be messing the
>>> hpts output up, but in my case I don't output temperature or pressure.
>>>
>>> I looked at the hpts routine and noticed that it uses pm1 when it is
>>> stacking the field variables into the working array.  Since I am using
>>> a Pn-Pn-2 formulation for my case, do I need to use the mappr
>>> subroutine in my usrchk to map the pressure from mesh 2 to mesh 1
>>> before calling hpts()?
>>>
>>> I'm assuming the issue arises because I am calling hpts more
>>> frequently than I am outputing field files, and thus perhaps pm1 isn't
>>> properly being updated (or perhaps it may have already been
>>> destroyed).
>>>
>>> Thanks,
>>>
>>> --
>>> Josh Camp
>>>
>>> "All that is necessary for the triumph of evil is that good men do
>>> nothing" -- Edmund Burke
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>>
>>
>>
>> --
>> Josh Camp
>>
>> "All that is necessary for the triumph of evil is that good men do
>> nothing" -- Edmund Burke
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