[FLASH-USERS] QuickFlash Interpolation Question

[Nathan Hearn]

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


-- 
Nathan C. Hearn
nhearn at ucar.edu

Project Scientist
Computational & Information Systems Laboratory
National Center for Atmospheric Research


On Mon, Feb 15, 2010 at 10:06, Samuel Friedman <friedman at astro.wisc.edu> wrote:
> Dear FLASH people,
>
> I'm trying to port some of my analysis code from IDL to C++ and one of the
> things I need to do is to generate a uniform grid of values from a 3D
> simulation that uses Cartesian coordinates.  Using fidlr3.0, I can do this
> very simply:
>
> density = loaddata('filename_hdf5_0000','dens',/double)
>
> I have looked at QuickFlash and I do not know how to do this.  There are
> some routines for slices but I need the full grid.  There is one previous
> email about this topic in the flash-users archive but there was never a
> response to this issue.  Can somebody tell me how to execute the above
> code using QuickFlash?
>
> Thanks,
> Sam
>
> Samuel Friedman
> Graduate Student
> Department of Astronomy
> University of Wisconsin