[Nexus-developers] Extendible datasets

[Mark Koennecke]

Dear Stephane,

POIRIER Stephane wrote:
> Hi all,
>
> Up to now, using napi 4.0, it's possible to create one dimension uncompressed extensible datasets using HDF5. Would it be possible to add the possibility to create extendible dataset of two or more dimensions ?
>
>   
The NAPI currently only supports one unlimited dimension which must be 
the first. This has been inherited from
HDF-4 which only supports this. With HDF-5 it is now possible to have 
more then one unlimited dimension.
The use of HDF-4 is more or less deprecated, so this would be an 
argument to support to add this for NAPI.
But implementing general unlimited dimensions for XML would be another, 
serious problem.
> Looking at napi5.cpp the limitation seems coming from the dataset creation were only the first dimension may be set as unlimited.
> Here is a example explain how to do it using the HDF5 api: http://beige.ucs.indiana.edu/I590/node133.html
>
> One another limitation is I can't create compressed dataset of unlimited size. I think it's a bug because NX5compmakedata seems support unlimited size datasets.
>   
I have to see your code. I write compressed datasets along an unlimited 
dimension routinely.

                 Best Regards,

                        Mark
> Thanks for your attention.
>
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