NCCMP(1)

NAME
nccmp - Compare two NetCDF files

SYNOPSYS
nccmp [OPTION]... FILE1 [FILE2]

DESCRIPTION
nccmp compares two NetCDF files bitwise, semantically or with a user defined tolerance. Comparisons are done in local memory without requiring temporary files.

OPTIONS

  -A, --Attribute=att1[,...]
Ignore attribute(s) att1[,...] for all variables.

  -b, --verbose
Print messages to show progress.

  -c, --var-diff-count=COUNT
Stop comparing a variable after COUNT data diffs.

  -C, --diff-count=COUNT
Stop comparing after COUNT data diffs total for all variables.

  -d, --data
Compare data (variable values).

  -D, --debug
Prints verbose debug messages.

  -e, --encoding
Compare these variable encoding settings: checksum, chunk, deflate, endianness, shuffle, szip

  -f, --force
Forcefully compare, do not stop after first difference.

  -F, --fortran
Print position indices using Fortran style (1-based column major order), instead of C style (0-based row major).

  -g, --global
Compare global attributes. (auto enables -m)

  -G, --globalex att1[,...]
Exclude global attributes att1[,...]. (auto enables -g)

  -h, --history
Compare global history attribute. (auto enables -g)

  -H, --help, --usage
Print usage message.

  -i, --info
Print file structure info for one or both files.

  -l, --color
Print colored messages.

  -m, --metadata
Compare metadata. Use -g to include global attributes.

  -M, --missing
Ignore difference between values that have different "missing_value" and/or "_FillValue" attributes. Attribute metadata differences are still reported.

  -n, --threads=N
Use N POSIX threads. Default is 1.

  -N, --nans-are-equal
Allow NaNs to be equal.

  -p, --precision=FMT
Global format precision of difference printing. Use '%x' to print bytes as hex string.

FMT defaults differently per data type:
    double '%g'
    float '%g'
    int '%d'
    int64 '%lld'
    schar '0x%02X'
    short '%d'
    text '%c'
    uchar '0x%02X'
    uint '%d'
    uint64 '%llu'
    ushort '%d'

  -P, --header-pad
Compare header padding in NetCDF3 classic and 64bit file formats.

  -q, --quiet
Do not print metadata or data differences.

  -r, --group=group1[,...]
Compare group(s) group1[,...] only. Group names can be full or short. "/" is the file root group. "/group1/subgroup2" is an example fullname, whereas "group1" and "subgroup2" are short names.

  -s, --report-identical-files
Report when files are the same.

  -S, --statistics
Report data difference statistics summary table after all comparisons.

  -t, --tolerance=TOL
Compare if absolute difference > TOL.

  -T, --Tolerance=TOL
Compare if relative percent difference > TOL.

  -v, --variable=var1[,...]
Compare variable(s) var1[,...] only.

  -V, --version
Print program version.

  -x, --exclude=var1[,...]
Exclude variable(s) var1[,...].

  -w, --warn=tag[,...]
Selectively make certain differences exceptions, but still print messages. As warnings, these differences will not return exit code 1.

Supported tags and their meanings:
    all: All differences.
    format: File formats.
    eos: Extra attribute end-of-string nulls.

EXAMPLES

  Print file structure info
$ nccmp -i encoded.nc

  Compare metadata and exclude specific variables
$ nccmp -mf -x recdata,rec test1a.nc test1b.nc

  Compare data and allow differences up to a threshold
$ nccmp -df -t 1e-3 test4a.nc test4b.nc

  Run in parallel and report table up to 5 differences per variable
$ nccmp -df -S --threads 4 -c 5 in1.nc in2.nc

BUGS
No known bugs. Report bugs with bug tracker: <http://sourceforge.net/p/nccmp/bugs/>

AUTHOR
Remik Ziemlinski

COPYRIGHT
Copyright © 2004-2015 Remik Ziemlinski. License GPLv2: GNU GPL version 2 <http://gnu.org/licenses/gpl.html>. This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.