parallel netCDF

[John Tannahill]

Jianwei,

A quick follow-on and something else you may have already taken
care of.  I have finally gotten my latest Fortran test code to
run correctly.  The last thing I had to do is subtract 1 from
each of the netCDF start points.  Again, I think a C versus
Fortran issue.  Believe this needs to be fixed as well, but
like I say, something you may already be aware of.

Anxiously awaiting the next release,
John

Jianwei Li wrote:
> 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
>>============================
>>
> 
> 
> 


-- 
============================
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
============================