[FLASH-USERS] restart PM run in UG mode

[Alexander Wagner]

Dear Anshu and Tomek,

Many thanks for your quick replies. I'll give Tomek's suggestion a go 
and see if it's fast enough. I will let you know if I manage to write a 
utility to read in AMR data into UG.

Cheers,
Alex



Tomasz Plewa wrote:
> The simplest way of eliminating most of the AMR overhead is to set
> lrefine_min=lrefine_max upon restart, dump a checkpoint after the first
> mesh refinement, and restart again but now with nrefs=0.
>
> It will not be as fast as real UG, but estimating possible gains is not
> straightforward. If I remember correctly and for simple hydro, the above
> approach offers gains provided the filling factor exceeds about 0.3.

Anshu Dubey wrote:
> Alex,
>
> As the FLASH code is now you will have to start a new run and read the
> initial conditions manually from the checkpoint. Better still, you
> could consider creating a utility to read in AMR data into the UG grid
> and contributing it to the code base.  We do take contributions from
> users and acknowledge those contributions in the user's guide. If you
> choose to do this, we will give much technical help.
>
> Anshu
>
> On Mon, Mar 29, 2010 at 6:49 PM, Alexander Wagner
> <alexander.y.wagner at googlemail.com> wrote:
>   
>> Dear FLASH developers/users,
>>
>> Just a quick question, as I can't find the answer in the manual or mailing
>> list archive;
>>
>> Is it possible to restart an AMR simulation in UG mode with a checkpoint
>> file created in PM mode? Or does it involve starting a new run and reading
>> in the initial conditions from the checkpoint file manually.
>>
>> I can imagine this being a scenario commonly required when the flow in a
>> simulation (especially in 3D) becomes more complex and fills larger portions
>> of the domain; at some point most of the domain is maximally refined and the
>> overhead in AMR exceeds the advantages of using AMR.
>>
>> Many thanks,
>> Alex
>>
>>
>>
>>