[FLASH-USERS] QuickFlash Interpolation Question

Tomasz Plewa tplewa at fsu.edu
Wed Feb 17 13:19:41 EST 2010


Sam -

Have you tried VisIt? I am not sure what are you exact needs, but VisIt 
is more than just visualization tool, but offers a strong and growing 
capability for data analysis.

VisIt is available at

https://wci.llnl.gov/codes/visit/

and there exists large and active group of users/developers,

http://www.visitusers.org/index.php?title=Main_Page

Tomek
--
Samuel Friedman wrote:
> Dear Nathan,
>
> I played around with the code and looked at fidlr's merge_amr routine.  A 
> few things I noticed:
>
> 1)  I managed to create very easily a 3D uniform grid from AMR data by 
> simply modifying the example routine in map_uniform.  Quite easy.
> 2)  fidlr's merge_amr routine calls either the IDL function congrid (in 
> 2D) or rebin (in 3D).  In both cases, they simply use nearest neighbor 
> sampling.  So I think the "interpolation" should be really easy to 
> implement for QuickFlash.
> 3)  This is harder, but I tried using map_uniform on a simulation that 
> used a uniform grid and QuickFlash gave me an error message (about an 
> invalid neighbor code and that mesh information was not available).
>
> The main reason I looked into QuickFlash is that it was pretty much the 
> ONLY set of tools outside of IDL avaiable for analysis.  Ultimately, I 
> am looking for something without IDL's licensing agreement and fidlr3.0 
> does not seem to work properly with GDL.
>
> Sam
>
> On Wed, 17 Feb 2010, Nathan Hearn wrote:
>
>   
>> Hi Sam,
>>
>>     Thank you very much for your interest in QuickFlash -- providing
>> basic tools for developing your own analysis software is what I
>> intended by releasing it!  Indeed, the now-quite-old 1.0.0 release has
>> only very simple sampling methods for automated extraction of data
>> over large areas.  [Massimo: I do apologize for missing your question
>> about slicing in October.  I hope that the current discussion is of
>> interest to you.]  QuickFlash's strength continues to be
>> high-performance access to raw block data.  However, my desire is to
>> have a simple, consistent set of data structures for holding
>> interpolated data, and interpolation routines compatible with the
>> ghost-cell generation in Paramesh.  (I have not determined how
>> Paramesh's inter-block interpolation compares to the method used in
>> Fidlr's merge_amr routine that is called by loaddata.)
>>
>>     I have been working on some significant functional improvements to
>> the QuickFlash library, and I hope to have an interpolation
>> infrastructure in the next release.  Unfortunately, development of the
>> library is a one-person operation at this point, and is separate from
>> the work of my current research position, so I can not make any
>> guarantees about how soon it will be available.  (But I can make
>> interpolation a priority.)
>>
>>     In the meantime, I can certainly provide you with examples of
>> filling a uniform mesh with values based on sub-sampling, but they
>> would still lead to blocky structure as seen in slices that cover a
>> wide range in refinement.  If you wish to develop interpolation
>> routines for your own codes using QuickFlash (or help me with
>> developing ones within library), I would be more than happy to assist
>> you.
>>
>>
>> - Nathan
>>
>>
>>
>>     
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