[netcdfgroup] netCDF Operators NCO version 5.0.3 are on tap

• To: NCO Announce Mail List <nco-announce@xxxxxxxxxxxxxxxxxxxxx>, netCDF Mail List <netcdfgroup@xxxxxxxxxxxxxxxx>
• Subject: [netcdfgroup] netCDF Operators NCO version 5.0.3 are on tap
• From: Charlie Zender <zender@xxxxxxx>
• Date: Wed, 6 Oct 2021 15:41:19 -0700

The netCDF Operators NCO version 5.0.3 are on tap.

http://nco.sf.net (Homepage, Mailing lists, Help)
http://github.com/nco (Source Code, Issues, Releases, Developers)

What's new?
Version 5.0.3 contains significant improvements to the quantization
algorithms and fixes to MOAB/mbtempest regridding. NCO now supports
the Digit Round and Granular BitGroom quantization algorithms. The
failed self-test problems that prevented Conda from building NCO
5.0.2 have been fixed, and a 5.0.3 Conda package will soon be
available.

Work on NCO 5.0.4 has commenced and will improve ncremap support
for MOAB, incorporate new MOAB improvements, and further improve
quantization metadata and algorithms.

Enjoy,
Charlie

NEW FEATURES (full details always in ChangeLog):

A. Lossy quantization algorithms have been refactored. First, the
   attribute name that store the level of quantization are now
   algorithm-specific, e.g.,
   QuantizeBitGroomNumberOfSignificantDigits. Previsously, NCO
   stored the NSD attribute number_of_significant_digits. However,
   this was deemed too ambiguous, given the increasing number of
   supported quantization methods. The new attribute names better
   disambiguate which algorithm was used to quantize the variable.
   Second, the default algorithm has been changed from BitGroom with
   BitRound masks from R. Kouznetsov (2021), to what we call Granular
   BitGroom (GBG). GBG combines features of BitGroom,
   BitRound, and DigitRound by Delaunay et al. (2019). GBG improves
   compression ratios by ~20% relative to BitGroom for NSD=3 on
   our benchmark 1 GB climate model output dataset.
   ncks -7 -L 1         --ppc default=3 in.nc out.nc # GranularBitGroom
   ncks -7 -L 1 --baa=0 --ppc default=3 in.nc out.nc # BitGroom
   ncks -7 -L 1 --baa=1 --ppc default=3 in.nc out.nc # BitShave
   ncks -7 -L 1 --baa=2 --ppc default=3 in.nc out.nc # BitSet
   ncks -7 -L 1 --baa=3 --ppc default=3 in.nc out.nc # DigitRound
   ncks -7 -L 1 --baa=4 --ppc default=3 in.nc out.nc # GranularBitGroom
   ncks -7 -L 1 --baa=5 --ppc default=3 in.nc out.nc # BitRound
   ncks -7 -L 1 --baa=6 --ppc default=3 in.nc out.nc # HalfShave
   ncks -7 -L 1 --baa=7 --ppc default=3 in.nc out.nc # BruteForce
   Documentation on Bit-Adjustment-Algorithms (BAA) 3-7 will be
   improved in the future. Bit-Groom/Shave/Set are described here:
   http://nco.sf.net/nco.html#ppq
   http://nco.sf.net/nco.html#gbg

BUG FIXES:

A. ncremap fixes issues that caused a self-test to fail.
   This prevented Conda from building an NCO 5.0.2 package.
   The tested algorithm is now 'fv2fv_flx' not 'tempest'. The
   MPI-enabled E3SM-Unified (SYSTEM) environment no longer changes
   the behavior of ncremap commands. --mpi_nbr now has complete
   control over whether mpirun (or srun) commands are issued.

Full release statement at http://nco.sf.net/ANNOUNCE
--
Charlie Zender, Earth System Sci. & Computer Sci.
University of California, Irvine 949-891-2429 )'(