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From: Charlie Zender <zender@uc...>  20090715 23:21:18

The netCDF operators NCO version 3.9.9 are ready. http://nco.sf.net (Homepage) http://dust.ess.uci.edu/nco (Homepage "mirror") This version offers six new significant features: GSL statistics routines, GSL interpolation routines, netCDF4 chunksize support (can increase speed of large file reads and writes), netCDF4 string support, record coordinate "rebasing" (climate model analysts take note!), and onedimensional offsets in ncap2. Short explanations of these appear below. This is the most featurefull release in quite some time. Work on NCO 4.0.0 is underway. Areas of improvement include more GSL interpolation and fitting functions, and bilinear interpolation. "New stuff" details: A. ncrcat supports "rebasing", a new feature that relies on UDUnits. When concatenating multiple input files whose record dimension uses a units attribute convention like "timesince", and whose base times vary amongst the files (e.g., "timesince 20010101" in the first file and "timesince 20020101" in the second), ncrcat now automatically rebases the record coordinate values in the output file so that they all refer to the same base time. This often produces a monotonically increasing record coordinate in the output file. Analysis of climate model output in CMIP3 type collections will be easier as a result. B. ncap2 supports the GSL (Chapter 20) statistics routines, e.g., ncap2 v O s 'defdim("dmn",100);sigma[dmn]=1.0;var1=gsl_ran_gaussian(sigma);var2=gsl_stats_skew(var1);print(var2)' in.nc out.nc ncap2 functions added since 3.9.8 are listed below http://nco.sf.net/nco.html#gsl C. NCO supports netCDF4 chunking options: These options can improve performance on large datasets. Large file users: Send us suggestions on useful chunking patterns! More advanced chunking patterns will be implemented in NCO 4.0.0. ncks O 4 cnk_plc=all in.nc out.nc http://nco.sf.net/nco.html#chunking D. NCO supports the netCDF4 NC_STRING atomic type. NCO has longsupported the other netCDF4 atomic types. An "s" trailing double quotes specifies NC_STRING (not NC_CHAR): ncap2 4 O v s 'name[lat]={"US"s,"Them"s};' in.nc out.nc Ragged arrays of strings are finally here! Let's use them. http://nco.sf.net/nco.html#nco4 E. ncap2 supports GSL (Chapter 27) interpolation routines, e.g., gsl_interp_cspline(). Also, missing values handling is improved. http://nco.sf.net/nco.html#gsl F. ncap2 LHS hyperslabs of multidimensional variables work with a single index corresponding to the 1D array offset, e.g., three_dmn_var_dbl(1,1,2)=10.0 is same as three_dmn_var_dbl(14)=10.0 http://nco.sf.net/nco.html#xmp_ncap2 G. UDUnits2 support completed. "time since" handled correctly. All future units features will utilize UDUnits2. UDUnits1 support will eventually be deprecated. H. Operators add an NCO global attribute containing NCO version I. ncks secret prints hidden/unsupported options "Sticky" reminders: K. Prebuilt, uptodate Debian Sid & Ubuntu Intrepid packages: http://nco.sf.net#debian L. Prebuilt Fedora and CentOS RPMs: http://nco.sf.net#rpm M. Find/add NCO tips and tricks on the NCO Wiki: http://nco.wiki.sourceforge.net N. Did you try SWAMP (Script Workflow Analysis for MultiProcessing)? SWAMP efficiently schedules/executes NCO scripts on remote servers: http://swamp.googlecode.com SWAMP can work commandline operator analysis scripts besides NCO. If you must transfer lots of data from a server to your client before you analyze it, then SWAMP will likely speed things up. O. NCO support for netCDF4 features is tracked at http://nco.sf.net/nco.html#nco4 NCO supports netCDF4 atomic data types, compression, and chunking. NCO 3.9.9 with was built and tested with HDF5 1.8.3snap2 and with netCDF4 4.1beta1snapshot2009061712. NCO may not build with earlier, but should build with later, netCDF4 releases. This is particularly true with NCO 3.9.9 which takes advantage of an internal change to the netCDF API for nc_def_var_chunking(). export NETCDF4_ROOT=/usr/local/netcdf4 # Set netCDF4 location cd ~/nco;./configure enablenetcdf4 # Configure mechanism or cd ~/nco/bld;./make NETCDF4=Y allinone # Old Makefile mechanism P. Have you seen the NCO logo candidates by Tony Freeman and Rich Signell? http://nco.sf.net/logo_pch.png http://nco.sf.net/logo_cog.png Tell us what you think... Enjoy, Charlie GSL functions added to ncap2 in 3.9.9: ncap2 f  grep gsl_interp ncap2 f  grep gsl_stats gsl_interp_akima() gsl_interp_akima_periodic() gsl_interp_cspline() gsl_interp_cspline_periodic() gsl_interp_linear() gsl_interp_polynomial() gsl_stats_absdev() gsl_stats_absdev_m() gsl_stats_correlation() gsl_stats_covariance() gsl_stats_kurtosis() gsl_stats_lag1_autocorrelation() gsl_stats_lag1_autocorrelation_m() gsl_stats_max() gsl_stats_max_index() gsl_stats_mean() gsl_stats_median_from_sorted_data() gsl_stats_min() gsl_stats_min_index() gsl_stats_pvariance() gsl_stats_quantile_from_sorted_data() gsl_stats_sd() gsl_stats_sd_m() gsl_stats_sd_with_fixed_mean() gsl_stats_skew() gsl_stats_ttest() gsl_stats_variance() gsl_stats_variance_m() gsl_stats_variance_with_fixed_mean() gsl_stats_wabsdev() gsl_stats_wabsdev_m() gsl_stats_wkurtosis() gsl_stats_wkurtosis_m_sd() gsl_stats_wmean() gsl_stats_wsd() gsl_stats_wsd_m() gsl_stats_wsd_with_fixed_mean() gsl_stats_wskew() gsl_stats_wskew_m_sd() gsl_stats_wvariance() gsl_stats_wvariance_m() gsl_stats_wvariance_with_fixed_mean()  Charlie Zender, Department of Earth System Science University of California, Irvine (949) 2317002 :) 