Hi Chris,
We use record and unlimited interchangeably.
A record dimenison is an unlimited dimension.
> if you had a 1-d variable of records, would that mean chunks equal the
> record size? 'cause that would be way too small in the common case.
yes, the rd1 map is not good for access speeds on 1D vars.
use the --cnk_dmn=time,sz option to override this. or use lfp map...
> Not so clear from the amount of time I've spent reading that, but what
> would be the default chunking for a 1-d unlimited variable? or a 2-d,
> with one dimension very small (Nx3, for instance)?
for lfp map these are [N] and [N/3,3] where N is total chunksize, as
you can see with these commands:
ncks -O -4 --cnk_plc=all --cnk_map=lfp ~/nco/data/in.nc ~/foo.nc
ncks -m --cdl --hdn ~/foo.nc
> Those were the use cases where the default chunking in netcdf4
> killed us.
We may change the NCO default map from rd1 to lfp or something
similar in 4.4.1.
Your feedback is helpful!
c
--
Charlie Zender, Earth System Sci. & Computer Sci.
University of California, Irvine 949-891-2429 )'(
