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[netCDF #ESK-579185]: Re: access to /glade file that demos large block size performance problem

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  • Subject: [netCDF #ESK-579185]: Re: access to /glade file that demos large block size performance problem
  • Date: Wed, 04 Jan 2012 16:27:37 -0700
> Ahhh - that makes sense. Does make using the ncid as a subscript for various 
> purposes a bit tricky, though.

Yup, but you can get the fileid and groupid out of the ncid (which is called 
the "locid
in much of the documentation) by just dividing by 65536 or taking remainder of 
dividing 
by 65536, respectively.

--Russ

> >> Unrelated, but a quick question - why are the ncid values I get from
> >> nf_open so large and in units of 65,536?
> >
> > Good question, it's an artifact of how netCDF-4 combines both the file
> > ID and the group ID into one 32-bit integer for netCDF-4.  So with
> > 2^16 open files each of which has 2^16 groups, you would use up all the
> > 2^32 integers with group IDs of open netCDF files.
> >
> > --Russ

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



Ticket Details
===================
Ticket ID: ESK-579185
Department: Support netCDF
Priority: Normal
Status: Closed