newcprnc/README

Tool to compare CAM or CLM history files.

Building the executable:

cprnc is a Fortran-90 application. It relies on netcdf version 3 or
later. F90 support DOES NOT need to exist in the netcdf library. Easiest case
scenario for a successful build of cprnc is to simply run "gmake" or one of
its aliases in this directory. The build will fail if netcdf include files
and library files are not in the default locations of /usr/local/include and
/usr/local/lib, respectively. These default locations (specified as Makefile
macros) can be overridden by setting environment variables INC_NETCDF and
LIB_NETCDF to the proper values. The Makefile has entries for IRIX64, AIX,
OSF1, SUN, and Linux.  On Linux, entries exist for pgf90 and lf95
compilers. The Makefile is extremely simple, so adding support for new
architectures or compilers should be a piece of cake.

What it does:

cprnc is an analysis tool for gathering and printing statistics about
variables on 1 or 2 CAM or CLM history files. Simplest invocation is: "cprnc
file1.nc [file2.nc]".  Command-line arguments are available (e.g. for
printing variable values in a user-specified subdomain). An explanation of
cmd-line options is printed by running "cprnc" with no arguments. When given
one or two input files, the code prints a summary of statistics for variables
on the file(s) which are dimensioned something by time. For example, field max,
min, and i,j,k positions of these values are printed for each time index. If
two files are input, difference statistics are also printed for each field
which exists on both files.  For example, max absolute difference, max
relative difference, and positional information are printed. The relative
difference is defined as abs(v1-v2)/(2*max(abs(v1), abs(v2))), where v1 and
v2 represent variable values from file1 and file2, respectively. The factor
of 2 in the denominator of this expression is a convenience for computing the
worst case number of matching decimal digits, which is also printed.

Sample usage:

newcprnc <file1> <file2>

