Re: question about HDF5 parallel use of unlimited dimensions...

On Wed, 29 Jun 2005, Ed Hartnett wrote:

> Howdy all!
> I have a question about parallel programming with HDF5. Do parallel
> programmers just not use unlimited dimensions?
You can use unlimited dimensions for parallel programming.
> I noticed that H5Dextend is a collective operation. This would make it
> difficult for programs to add a record at a time.

I don't think it is difficult as long as all processors participate.

I may miss something. Parallel NetCDF tests I wrote include unlimited 
dimension dataset tests for both collective and independent modes. Tests 

Although H5Dextend is collective, I remember that I noticed that doesn't 
matter for netCDF4 users. I may be wrong. Maybe other people can give 
some insights.


 > Alternatively I could imagine a scheme where extending the 
dataset > would be buffered - some large number of records could be added
> whenever the current batch is used up.
> Any thoughts or comments about the use or misuse of unlimited
> dimensions with HDF5 parallel would be most welcome.
> Thanks!
> Ed