# This is a script in Bash.
# Author: Lionel GUEZ

# This script is a wrapper for a Fortran program. It compares NetCDF
# variables of type "NF90_FLOAT" or "NF90_DOUBLE" and of rank 1 to 4
# in two files. NetCDF variables are read into Fortran variables of
# type "double precision". The program computes the maximum of the
# absolute value of the difference and the maximum of the absolute
# value of the relative difference. The program either compares
# variables with the same varid or variables with the same name, or a
# single variable selected on the command line. Compared variables are
# assumed to have the same type. The program checks that compared
# variables have the same shape.

USAGE="usage: `basename $0` [-s] [-m] [-i] [-q] [-v <var>] file file
   -s: report identical variables
   -m: compute average order of magnitude
   -i: compare variables with same varid, regardless of variable name
   -q: only report names of variables which differ, without maximum difference
   -v <var>: only compare variable <var>"

# Default values:
report_id=False
comp_mag=False
same_varid=False
quiet=False

while getopts smiqv: name
  do
  case $name in
      s) report_id=True;;
      m) comp_mag=True;;
      i) same_varid=True;;
      q) quiet=True;;
      v) name1=$OPTARG;;
      \?) echo "$USAGE"
      exit 1;;
  esac
done

shift $((OPTIND - 1))

if (($# != 2))
    then
    echo "$USAGE" >&2
    exit 1
fi

##set -x
trap 'exit 1' ERR

for argument in $*
  do
  if [[ ! -f $argument ]]
      then
      echo "$argument not found"
      exit 1
  fi
done

max_diff_nc=...
if [[ ! -x $max_diff_nc ]]
    then
    echo "Fortran executable not found" >&2
    exit 1
fi

ln -s $1 in1.nc
ln -s $2 in2.nc

trap 'rm in1.nc in2.nc; exit 1' ERR

# Run the Fortran program:
$max_diff_nc <<EOF
$same_varid
$report_id
$quiet
$comp_mag
$name1
EOF

rm in1.nc in2.nc