parallel netCDF

[Jianwei Li]

John,

Thanks for your feed back!

Don't worry, we had identified and taken care of this Fortran
dimension ordering issue in our current developing version of
parallel netCDF. Now, it should be running the same way as the
serial netCDF Fortran interface and you won't have to worry to
artificially transfer the Fortran dimension order into C order
explicitly within the user application code any more.

Jianwei

On Fri, 22 Aug 2003, John Tannahill wrote:

> A while back, I think there was some discussion about the order of
> dimensions with regards to C/Fortran.  In my original Fortran test
> code, I just mimicked the way things were done in NERSC's csnap.c
> code.  That is, in my Fortran code, I just used the same dimensioning
> order as the C code.  The Fortran code results then matched the C
> code results.
>
> Now I have written two additional Fortran codes.  One that mimics
> the way our Fortran modeling code currently does its netCDF I/O,
> which uses serial netCDF, the slaves read their portions of the
> large arrays, and the slaves communicate their array parts back
> to the Master for output, generally in some sort of round-robin
> fashion because of memory limitations on the Master.  Anyway, this
> test code is up and running.  Note also that this code uses
> Fortran ordering for everything and netCDF takes care of
> translating to the C ordering that it needs.
>
> The Fortran code that I am currently working on is using your
> parallel-netCDF library to replace the serial netCDF.  I do not have
> it working yet, but one issue that I have already run into is that
> I don't want to artificially "C order" things in this Fortran code,
> which I believe I currently will have to do.
>
> Anyway, I wanted to give you a heads up, as I believe this topic
> was under discussion a while back.  I do believe that your
> parallel-netcdf library will need to handle the conversion to
> C ordering itself and not have the application writer have to
> deal with it.  I hope this all makes sense, and note that I am
> down to my last couple of weeks that I will be able to devote
> much time to this work.  I am hoping that a new release will show
> up shortly?
>
> I am currently using version 0.8.9 on NERSC's IBM SP (seaborg).
>
> Regards,
> John
>
> --
> ============================
> John R. Tannahill
> Lawrence Livermore Nat. Lab.
> P.O. Box 808, M/S L-103
> Livermore, CA  94551
> 925-423-3514
> Fax:  925-423-4908
> ============================
>