[MITgcm-support] mnc questions

[Ed Hill]

On Thu, 2005-12-15 at 21:31 -0600, Michael Schaferkotter wrote:
> 
> i read the beta docs (i had used a data.mnc with 
> all default values in my first run. that/s what prompted
> and adjusted the value of mnc_max_fsize to what i 
> thought was an appropriate value.

Hi Michael,

In order to use the mnc_max_fsize variable, you must have the ability to
link against C code that contains the stat() function.  This capability
is checked when you run genmake2 and see output that looks like this:

  Can we use stat() through C calls...  yes

If the answer you see is a "no" then the file size code is excluded and
setting mnc_max_fsize at runtime is a pointless exercise.  So please
check first that the HAVE_STAT define is set for your system.


>  mnc_max_fsize=3.0e+06,

The value you've set here is 3*10^6 bytes which is just a bit less than
3MB.  This is a mighty small value.  You might want to consider
increasing it.


> i don/t see why the files are the same size and i don/t 
> see why state.0000.000001.nc is over 289MB.
> i didn/t recompile.
> so what am i missing?

I think perhaps you don't have the ability to call the stat() function
but it may be something else.  So lets check the stat() think first and
then move on from there.

And have you looked inside the netCDF files?  Perhaps using ncdump or
ncview or the MatLAB mexcdf utilities?  NetCDF files may contain many
variables along with a lot of helpful metadata!  Honestly, they aren't
supposed to be all the same size!

Ed

-- 
Edward H. Hill III, PhD
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