[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: 950915: netCDF and NC_UNLIMITED woes

This archive contains answers to questions sent to Unidata support through mid-2025. Note that the archive is no longer being updated. We provide the archive for reference; many of the answers presented here remain technically correct, even if somewhat outdated. For the most up-to-date information on the use of NSF Unidata software and data services, please consult the Software Documentation first.

  • Subject: Re: 950915: netCDF and NC_UNLIMITED woes
  • Date: Fri, 15 Sep 1995 13:55:07 -0600
>Organization:  Geophysical Inst., Univ. of Alaska Fairbanks 
>Keywords: 199509151936.AA08228

Hi Dave,

> I think my last email didn't get sent properly, so to summarise I have a
> similar problem that one person had on the support email replies, but I didn't
> see a solution. Basically I am trying to write a variable with an unlimited
> dimension, but ncdump shows me only the header. Here is a sample piece of code
> which has the problem.
> 
> If I specify a finite time dimension it works fine. Thanks for your time.
> 
> Regards,
> 
> Dave
> 
> #include "netcdf.h"
> 
> #define TIMES 3
> #define LATS  5
> #define LONS  10
> 
> main() {
> int  ncid;                         /* netCDF ID */
> int  rh_id;                        /* variable ID */
> static long start[] = {0, 0, 0};    /* start at first value */
> static long count[] = {1, LATS, LONS};
> int dimids[3];
> int time_def, lat_def, lon_def;
> double rh_vals[LATS*LONS];   /* array to hold values */
> int i,iret;
> 
> ncid = nccreate("foo.nc", NC_NOCLOBBER);
> lat_def = ncdimdef(ncid,"lat",LATS);
> lon_def = ncdimdef(ncid,"lon",LONS);
> time_def = ncdimdef(ncid,"times",NC_UNLIMITED);
> dimids[0] = time_def;
> dimids[1] = lat_def;
> dimids[2] = lon_def;
> rh_id = ncvardef(ncid, "rh", NC_DOUBLE, 3, dimids);
> iret = ncendef(ncid);
> 
> for (i = 0; i < LATS*LONS; i++)
>      rh_vals[i] = 0.5;
> 
> /* write hyperslab of values into netCDF variable */
> iret = ncvarput(ncid, rh_id, start, count, (void *) rh_vals);
> iret = ncclose(ncid);
> 
> }

I just tested your code here (on a SPARCstation 10/Solaris 2.4 with netCDF
2.3.2) and it seems to work as intended:

    test$ ncdump foo.nc
    netcdf foo {
    dimensions:
            lat = 5 ;
            lon = 10 ;
            times = UNLIMITED ; // (1 currently)

    variables:
            double rh(times, lat, lon) ;

    data:

     rh =
      0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5,
      0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5,
      0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5,
      0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5,
      0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5 ;
    }

Unless you are using "ncdump -h" or "ncdump -c" (which specifies not to
print the data), I don't see what the problem is.  If you'll tell me
what computer and OS you are using, maybe we can duplicate the problem here.
Thanks.

--Russ

______________________________________________________________________________

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