Help getting started with Pnetcdf

[michael]

On Mon, 2008-10-13 at 16:48 -0500, Robert Latham wrote:
> On Mon, Oct 13, 2008 at 04:07:52PM -0500, Nikhil Laghave wrote:
> > Hello All,
> > 
> > I have been using Parallel HDF5 for our code to do parallel IO of huge files
> > but the performance we're getting is not very encouraging. So I wanted to do
> > the same with Pnetcdf, but I am not able find much tutorials on the web with
> > simple examples to write out files in parallel. The ones that are there are
> > the serial ones.
> > 
> > So I was wondering if someone on this mailing list has a simple Pnetcdf
> > example, that will help me in understanding how to use pnetcdf.
> 
> Hi
> 
> We really could use some more in-depth tutorials.  Perhaps the best
> examples right now are those in the 'test' directory.   You can also
> use the serial netcdf as a starting point:  nfmpi_def_dim behaves just
> like nf_def_dim, for example, though you might have to adjust the size
> and types of some of your variables.
> 
> > Also, I am trying to create a simple file using pnetcdf and am getting this
> > error. There seems to be some problem with the include file and I don't
> > understand how to get rid of this error. My code is as follows:
> 
> I think I see what's wrong here.  Two things, one small and one
> larger.
>  
> >       nfmpi_create(MPI_COMM_WORLD,FILE_NAME,
> >      &     NF_NETCDF4,MPI_INFO_NULL,ncid)
> 
> The NF_NETCDF4 flag doesn't have any meaning in pnetcdf land, but I
> don't think this why you are having problems. 
> 
> > When i compile this using : ftn simple.f $PNETCDF, i get this error.
> > 
> > PGF90-S-0021-Label field of continuation line is not blank
> > (/usr/common/usg/pnetcdf/1.0.2/include/pnetcdf.inc: 1816)
> 
> line 1816 is:
> #define NF_INT1_IS_C_SIGNED_CHAR 1
> 
> We require our fortran codes to use the C preprocessor.  For many
> compilers, this means using the '.F' suffix, or take Jim Edward's
> advice.
> 
> People have used the portland group compilers with parallel-netcdf, so
> I bet we can get you back on track in short order.
> 
> ==rob


I can dig out my examples and offer up, perhaps we could create a Wiki
for people to upload (and improve!) examples? 

I don't know if there's {m}any UK {academic-related} people on the list
but here's an event you may be interested in on 4 Dec 2008 in NW
England: http://www.hpcx.ac.uk/about/events/parallel_io.html (albeit
apparently more application than lower level focussed). Feel free, when
booking/enquiring, to said I advertised this to you.

M