[FLASH-USERS] QuickFlash Interpolation Question

[Samuel Friedman]

Dear Tomek,

I just looked at VisIt and it does not appear to satisfy my needs.  In 
short, I need to generate a uniform grid of the data.  If you know how to 
do this with VisIt, I'll listen; I looked through VisIt's manuals and 
there is no mention about it in the manuals. 

Sam


On Wed, 17 Feb 2010, Tomasz Plewa wrote:

> 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
> > >
> > >
> > >
> > >     
> 
>