[Nek5000-users] Restart with geometry changes

[nek5000-users at lists.mcs.anl.gov]

Markus,

If you're using .fld files, you can simply modify your .rea file:

:
:
             1 PRESOLVE/RESTART OPTIONS  *****
my_old.fld01  U P T time=0
:
:
:


which tells nek to take _only_ U P T and from the .fld
file (assuming they are present), and to not take anything
else.   Also, it tells it to reset time to 0 at the start
of this calculation.   Note that if you have, say,

             2 PRESOLVE/RESTART OPTIONS  *****
my_old.fld01  U P T time=0
my_old.fld02    P T


it would take U from fld01 and P, T, and time from fld02.


I don't believe we have this level of support in the .f0000
format yet, but I can possibly put someone on it.

In your case (assuming you're using .f0000 format), you can
instead do the following in usrdat2 (by which point nek
knows the geometry, but has not yet read initial conditions):


c-----------------------------------------------------------------------
       subroutine usrdat2
       include 'SIZE'
       include 'TOTAL'
       parameter (ltt=lx1*ly1*lz1*lelt)
       common /cmygeom/ xmo(llt),ymo(llt),zmo(llt)

       call opcopy(xmo,ymo,zmo,xm1,ym1,zm1)  ! Preserve my geometry

       return
       end
c-----------------------------------------------------------------------
       subroutine usrchk
       include 'SIZE'
       include 'TOTAL'
       parameter (ltt=lx1*ly1*lz1*lelt)
       common /cmygeom/ xmo(llt),ymo(llt),zmo(llt)

       call opcopy(xm1,ym1,zm1,xmo,ymo,zmo)  ! Restore my geometry

       call geom_reset(1)                    ! Force regen. of Jacobians etc.

       return
       end
c-----------------------------------------------------------------------


Paul


On Thu, 10 Mar 2011, nek5000-users at lists.mcs.anl.gov wrote:

> Howdy Neks,
>
> I ran a simulation on a certain geometry, saved solution files and would now 
> like to restart the same run from a given time step. The difference is that I 
> have implemented a geometry change via usrdat, but when I reload the previous 
> solution (which contains xyz), it overwrites my changes and uses the geometry 
> on which the solution was originally computed.
>
> To work around this, is it OK to just comment out line 367 in ic.f?
> c         call geom_reset(1)  !  recompute geometric factors
> Would this cause the old data to be mapped onto the new grid?
>
> Thanks,
> Markus
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