[netCDF #PDL-125161]: Writing parallel files with zero-size chunks

I wrote:
> Sorry, I see I was confusing your support ticket with another similar 
> question that
> asked whether having count[i]==0 for any i in nc_put_var calls was permitted 
> on
> parallel platforms.
> 
> Now I've compiled and run the bug demonstration code you provided and have 
> reproduced
> the problem, resulting in hanging at the same place you observed:
> 
> $ mpirun -n 5 ./nc4partest
> mpi_name: spock.unidata.ucar.edu size: 5 rank: 0, isDataWriter=0
> mpi_name: spock.unidata.ucar.edu size: 5 rank: 1, isDataWriter=0
> mpi_name: spock.unidata.ucar.edu size: 5 rank: 2, isDataWriter=1
> mpi_name: spock.unidata.ucar.edu size: 5 rank: 3, isDataWriter=0
> mpi_name: spock.unidata.ucar.edu size: 5 rank: 4, isDataWriter=0
> mpi_rank=0 start[0]=0 start[1]=0 count[0]=0 count[1]=0
> mpi_rank=2 start[0]=0 start[1]=0 count[0]=24 count[1]=24
> mpi_rank=3 start[0]=0 start[1]=0 count[0]=0 count[1]=0
> mpi_rank=4 start[0]=0 start[1]=0 count[0]=0 count[1]=0
> mpi_rank=1 start[0]=0 start[1]=0 count[0]=0 count[1]=0
> mpi_rank=1 start[0]=0 start[1]=0 count[0]=0 count[1]=0  C-c C-cCtrl-C 
> caught... cleaning up processes

I should have mentioned that I also tried to issuing nc_create_par with 
NC_MPIPOSIX 
and nc_var_par_access with flag NC_INDEPENDENT, for which you claimed you got
invalid output.  When I compiled and ran that, it appeared to run OK:

  $  mpirun -n 5 ./nc4partest2
  mpi_name: spock.unidata.ucar.edu size: 5 rank: 0, isDataWriter=0
  mpi_name: spock.unidata.ucar.edu size: 5 rank: 1, isDataWriter=0
  mpi_name: spock.unidata.ucar.edu size: 5 rank: 2, isDataWriter=1
  mpi_name: spock.unidata.ucar.edu size: 5 rank: 3, isDataWriter=0
  mpi_name: spock.unidata.ucar.edu size: 5 rank: 4, isDataWriter=0
  mpi_rank=0 start[0]=0 start[1]=0 count[0]=0 count[1]=0
  mpi_rank=1 start[0]=0 start[1]=0 count[0]=0 count[1]=0
  mpi_rank=2 start[0]=0 start[1]=0 count[0]=24 count[1]=24
  mpi_rank=3 start[0]=0 start[1]=0 count[0]=0 count[1]=0
  mpi_rank=4 start[0]=0 start[1]=0 count[0]=0 count[1]=0

and ncdump seems to show the output is a 24x24 array of the value 2,
which seems to me to be the expected value.  Have I misinterpreted
what you meant, or does this show that I can't reproduce that part
of your bug report?

--Russ

Russ Rew                                         UCAR Unidata Program
address@hidden                      http://www.unidata.ucar.edu



Ticket Details
===================
Ticket ID: PDL-125161
Department: Support netCDF
Priority: Normal
Status: Closed