[Users] yt visualization software for Carpet hdf5 data?

[Ian Hinder]

On 12 Mar 2012, at 17:06, Ian Hinder wrote:

> 
> On 12 Mar 2012, at 17:01, Roland Haas wrote:
> 
>> Hello Ian, Bruno,
>> 
>>> 	thanks for the info. I don't know if that format is supported, but I will ask.
>> To my knowledge (I wrote an xdmf xml generator for SpEC so had reason to
>> look into the specifications and source code), XDMF does not directly
>> support AMR meshes I believe. It does support subgrids, but not grids
>> where the fine grid overlaps the coarse one. At last there is nothing in
>> the file format that would allow you to specify something akin to
>> refinement levels or which region to prefer.
> 
> Right - when I first looked at it, this seemed to be the case.  But I think I looked at it more recently and it had developed somewhat.  Is that true?

It looks like you can have trees of "dataitems", so there is nesting information there.  For example, you could have RL0 as a tree containing all the dataitems (i.e. uniform HDF5 datasets) from RL0, and then have RL1 as a subtree of this.  The question is how this is supposed to be interpreted by the visualisation client.  This paper

http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4438005&tag=1

contains basically the same content as http://www.xdmf.org/index.php/XDMF_Model_and_Format, and they say that major work is done to support concepts such as AMR.  So presumably the intent is that the current format supports AMR.  My naive interpretation would be that within a tree structure, the parent items would logically contain the child items.  The client could then either simply provide a GUI for switching on and off child items, and render both parent and child when both are "on", or it could be intelligent and clip the parent items to remove the portions which are overlayed with the child items.  I remember Christian did some work in the VisIt plugin to make it aware of the containment relations between different Carpet datasets.  The question is whether the XMDF readers interpret the data in the same way.

-- 
Ian Hinder
http://numrel.aei.mpg.de/people/hinder