[Nek5000-users] Compute the derivatives

nek5000-users at lists.mcs.anl.gov nek5000-users at lists.mcs.anl.gov
Thu Jul 1 21:03:23 CDT 2010 

Michael,

time is "time" --- so you can trigger that way if you prefer it
to iostep/istep.

Paul



On Thu, 1 Jul 2010, nek5000-users at lists.mcs.anl.gov wrote:

>
>
> I think I see the issue, my iostep is set to zero because my iotime is 0.01.  Is there a way to check the time directly, and compare it to the iotime, rather than comparing the steps to iostep?
>
>
>
>
> ----- Original Message -----
> From: nek5000-users at lists.mcs.anl.gov
> To: nek5000-users at lists.mcs.anl.gov
> Sent: Thursday, July 1, 2010 8:25:35 PM GMT -06:00 US/Canada Central
> Subject: Re: [Nek5000-users] Compute the derivatives
>
>
>
>
> Aleks,
>
>
>
> Do I need to include anything in the header, or common block?  I added the condition statement, but the simulation quits on the first time step when it calls userchk.
>
>
>
> - Michael
>
>
> ----- Original Message -----
> From: nek5000-users at lists.mcs.anl.gov
> To: nek5000-users at lists.mcs.anl.gov
> Sent: Thursday, July 1, 2010 8:04:41 PM GMT -06:00 US/Canada Central
> Subject: Re: [Nek5000-users] Compute the derivatives
>
> Hi Michael,
>
>
> iostep dump works only for the dump of quantities specified as T in your .rea like
>
>   ***** OUTPUT FIELD SPECIFICATION *****
>             8 SPECIFICATIONS FOLLOW
>   T      COORDINATES
>   T      VELOCITY
>   T      PRESSURE
>   T      TEMPERATURE
>   F      TEMPERATURE GRADIENT
>             2      PASSIVE SCALARS
>  F
>  F
>
>
> Since userchk is called every timestep so you'll need something like
>
>
> if (mod(istep,iostep).eq.0) then
> ...
>
> Best,
> Aleks
>
>
>
> ----- Original Message -----
> From: nek5000-users at lists.mcs.anl.gov
> To: nek5000-users at lists.mcs.anl.gov
> Sent: Thursday, July 1, 2010 7:57:07 PM GMT -06:00 US/Canada Central
> Subject: Re: [Nek5000-users] Compute the derivatives
>
>
>
>
>
> Hi Paul and Aleks,
>
>
>
> I have a question regarding this. I have implemented this and it is working nicely, however it is dumping
>
> out a .f file every step, rather than every iotime step I have specified in the rea.
>
>
>
> Do you know how to fix this?
>
>
>
> - Michael
>
>
> ----- Original Message -----
> From: nek5000-users at lists.mcs.anl.gov
> To: nek5000-users at lists.mcs.anl.gov
> Sent: Wednesday, June 2, 2010 10:57:41 AM GMT -06:00 US/Canada Central
> Subject: Re: [Nek5000-users] Compute the derivatives
>
> Hi JC,
>
> To dump the computed derivatives into separate field files you can use in
> userchk
>
> ifxyo = .true. ! for cooordinates
> ifpo = .false. ! turn off pressure output
> ifto = .false. ! turn off pressure output
> call outpost(vxx,vxy,vxz,pr,t,'dvx')
> call outpost(vyx,vyy,vyz,pr,t,'dvy')
> ...
>
> Best,
> Aleks
>
>
>
> On Wed, 2 Jun 2010, nek5000-users at lists.mcs.anl.gov wrote:
>
>>
>> dudxyz is somewhat dated and slow...
>>
>> I recommend somthing like:
>>
>> parameter (lt=lx1*ly1*lz1*lelv)
>> common /mygrad/ vxx(lt),vxy(lt),vxz(lt)
>> $ , vyx(lt),vyy(lt),vyz(lt)
>> $ , vzx(lt),vzy(lt),vzz(lt)
>>
>> call gradm1(vxx,vxy,vxz,vx)
>> call gradm1(vyx,vyy,vyz,vy)
>> call gradm1(vzx,vzy,vzz,vz)
>>
>> Note that putting these arrays into a common block, as
>> shown, is a good idea for several reasons, one of which
>> is that it guarantees that the data will be byte-aligned with the cache line.
>> On some machines (e.g., BG/P) this
>> is crucial for proper functionality - for this reason we
>> don't mix variable types in a given common block.
>>
>> If you subsequently wish to access elements of vxx etc.
>> on an element-by-element basis you can of course do something
>> like
>>
>> parameter (lt=lx1*ly1*lz1)
>> common /mygrad/ vxx(lt,lelt),vxy(lt,lelt),vxz(lt,lelt)
>> :
>> :
>>
>> Paul
>>
>> On Wed, 2 Jun 2010, nek5000-users at lists.mcs.anl.gov wrote:
>>
>>> Hi Nek's,
>>>
>>> I have a home-made global stability code, but in order to use it I first
>>> need to compute the derivatives of my base flow: dUdX, dUdY, dVdX, dVdY.
>>> How could one compute these derivatives using Nek 5k and drop them along
>>> with X Y U V in the blah.f**** file (or perhaps another .f**** file) ? I
>>> assume I have to make use of the subroutine *dudxyz
>>> (du,u,rm1,sm1,tm1,jm1,imsh,isd)*, but I'm not sure what to put as inputs.
>>>
>>> Regards,
>>> JC
>>>
>> _______________________________________________
>> Nek5000-users mailing list
>> Nek5000-users at lists.mcs.anl.gov
>> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
>>
> _______________________________________________
> Nek5000-users mailing list
> Nek5000-users at lists.mcs.anl.gov
> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
>
> _______________________________________________
> Nek5000-users mailing list
> Nek5000-users at lists.mcs.anl.gov
> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
> _______________________________________________
> Nek5000-users mailing list
> Nek5000-users at lists.mcs.anl.gov
> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
>
> _______________________________________________ Nek5000-users mailing list Nek5000-users at lists.mcs.anl.gov https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users

More information about the Nek5000-users mailing list