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20010705: size of netCDF Fortran real

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  • Subject: 20010705: size of netCDF Fortran real
  • Date: Thu, 05 Jul 2001 09:52:35 -0600
Sue Yang,

> To: <address@hidden>
> From: "Xue (Sue) YANG" <address@hidden>
> Subject: Re: netcdf
> Organization: ?
> Keywords: 200107050049.f650nC104302 netCDF Fortran real

The above message contained the following:

> We've got netcdf installed on our Irix6.5 machine. We konw that the
> size of real variables for the netCDF external data types in the
> FORTRAN interface are 32 bits. We wonder whether we can change the
> size to 64 bits by recompiling the software? If so, would you give us
> any suggestions about how to do it?
> 
> Thanks!
> 
> Sue YANG

The size of netCDF variables of type NF_FLOAT and NF_DOUBLE are
32-bits and 64-bits, respectively. These sizes can't be changed. The
netCDF library is capable, however, of transferring netCDF NF_FLOAT
variables (32-bits) to and from 64-bit Fortran variables (of type REAL
or DOUBLEPRECISION -- depending on the platform). The library is also
capable of transferring netCDF NF_DOUBLE variables (64-bits) to and from
32-bit Fortran variables (although some loss of precision may occur).

If you wish to save values in a netCDF file using a 64-bit
floating-point representation, then I recommend defining the netCDF
variables as type NF_DOUBLE and transferring the values between whatever
Fortran variables are 64-bits wide on the system in question.  The
software should not need to be recompiled.

Contact me if you have further questions.

Regards,
Steve Emmerson   <http://www.unidata.ucar.edu>