[netCDF #ZMF-465105]: can not append data to an exist NETCDF file on cygwin platform

Xueming Zhu,

> Thanks for your replying. But if in that case, I have a question why
> I can not find any introduction of the nf90_put_vara from your link or
> the help file of netcdf interface( attached by this e-mail)? I just can
> find the interface nf90_put_var, and it looks like can be used to wroten
> an array to the netcdf variable. I know that there are an interface
> nf_put_vara for nf77. But never heard about the nf90_put_vara.

Oops, sorry, I forgot that the nf90_put_var interface already includes the
put_vara behavior if you provide the optional keyword arguments "start=..." 
and "count=...". You're right, that there is no separate function for using
those optional arguments, as there is in C, which didn't have optional
keyword arguments.

A Fortran-90 example using those arguments to write a record variable is here:

  
http://www.unidata.ucar.edu/software/netcdf/examples/programs/pres_temp_4D_wr.f90

--Russ

> 2013/8/23 0:34, Unidata netCDF Support ?:
> > Hi Xueming Zhu,
> >
> >> I tried to write data to an exist netCDF file with record variables
> >> on cygwin platform. My fortran codes as follow,
> >>
> >> clm  =trim(direc)//trim(casename)//'_monthly_'//year//'.nc'
> >> ierr=nf90_open(trim(clm),nf90_write,ncid)
> >> CALL HANDLE_ERR(ierr)
> >> do m=1,12
> >> ierr=nf90_inq_varid(ncid,'ocean_time',varid)
> >> CALL HANDLE_ERR(ierr)
> >> ierr=nf90_put_var(ncid,varid,dnum,start=(/ m /))
> >> CALL HANDLE_ERR(ierr)
> >> enddo
> >>
> >> the variable ocean_time's dimension is ocean_time, which is an
> >> unlimited dimension. At beginning, ocean_time's dimension is 1. But
> >> after the loop, it is 1 still. Some ncdump results as follow,
> >>
> >> $ ncdump.exe -v ocean_time np8_monthly_2002.nc
> >> netcdf np8_monthly_2002 {
> >> dimensions:
> >> tracer = 2 ;
> >> boundary = 4 ;
> >> s_rho = 22 ;
> >> s_w = 23 ;
> >> ocean_time = UNLIMITED ; // (1 currently)
> >> eta_rho = 633 ;
> >> xi_rho = 1545 ;
> >> eta_u = 633 ;
> >> xi_u = 1544 ;
> >> eta_v = 632 ;
> >> xi_v = 1545 ;
> >> variables:
> >>
> >> double ocean_time(ocean_time) ;
> >> ocean_time:long_name = "averaged time since
> >> initialization" ;
> >> ocean_time:units = "seconds since 1990-01-01 00:00:00" ;
> >> ocean_time:calendar = "gregorian" ;
> >> ocean_time:field = "time, scalar, series" ;
> >>
> >> I found the file size changed, but had not got any error when run the
> >> fortran code. It is weird for me.
> >>
> >> Can you give me any suggestions to fix the problem? Thanks a lot.
> > I think the problem is that you should be using nf90_put_vara
> > instead of nf90_put_var.  For an explanation why, see this section
> > of the nf90_put_var documentation:
> >
> >    
> > http://www.unidata.ucar.edu/netcdf/docs/netcdf-f90.html#NF90_005fPUT_005fVAR
> >
> > where it says:
> >
> >    Take care when using the simplest forms of this interface with
> >    record variables (variables that use the NF90_UNLIMITED dimension)
> >    when you don't specify how many records are to be written. If you
> >    try to write all the values of a record variable into a netCDF file
> >    that has no record data yet (hence has 0 records), nothing will be
> >    written. Similarly, if you try to write all the values of a record
> >    variable from an array but there are more records in the file than
> >    you assume, more in-memory data will be accessed than you expect,
> >    which may cause a segmentation violation. To avoid such problems, it
> >    is better to specify start and count arguments for variables that
> >    use the NF90_UNLIMITED dimension.
> >
> > --Russ
> >
> > Russ Rew                                         UCAR Unidata Program
> > address@hidden                      http://www.unidata.ucar.edu
> >
> >
> >
> > Ticket Details
> > ===================
> > Ticket ID: ZMF-465105
> > Department: Support netCDF
> > Priority: Normal
> > Status: Closed
> >
> >
> 
> 
> 
Russ Rew                                         UCAR Unidata Program
address@hidden                      http://www.unidata.ucar.edu



Ticket Details
===================
Ticket ID: ZMF-465105
Department: Support netCDF
Priority: Normal
Status: Closed