beam-eval-until-stable

#!/bin/bash

if [[ $# -ne 4 ]]; then
    cat <<EOF
ERROR: Missing -t and -r arguments.

Usage: Run this script with the same parameters as you would give
apertium-eval-translator.pl when running it without -beam, e.g.:

$0 -t test.txt -r ref.txt

This script will keep running apertium-eval-translator.pl with
doubling sizes of the -beam parameter until the result seems stable.
EOF
    exit 1
fi


last=-1

b=5

while true; do
    printf "Trying -beam %s …\t" "$b" >&2
    out=$("$(dirname "$0")"/apertium-eval-translator.pl -b $b "$@")
    cur=$(grep -m1 WER <<<"${out}")
    if [[ "$last" = "$cur" ]]; then
        echo "Stabilised; got the same result as with -beam $lastb: $cur" >&2
        echo "${out}"
        break
    else
        echo "got $cur" >&2
        lastb="$b"
        (( b += b ))
        last="$cur"
    fi
done