OFA-OCR / fairseq /scripts /build_sym_alignment.py
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# Copyright (c) Facebook, Inc. and its affiliates.
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.
"""
Use this script in order to build symmetric alignments for your translation
dataset.
This script depends on fast_align and mosesdecoder tools. You will need to
build those before running the script.
fast_align:
github: http://github.com/clab/fast_align
instructions: follow the instructions in README.md
mosesdecoder:
github: http://github.com/moses-smt/mosesdecoder
instructions: http://www.statmt.org/moses/?n=Development.GetStarted
The script produces the following files under --output_dir:
text.joined - concatenation of lines from the source_file and the
target_file.
align.forward - forward pass of fast_align.
align.backward - backward pass of fast_align.
aligned.sym_heuristic - symmetrized alignment.
"""
import argparse
import os
from itertools import zip_longest
def main():
parser = argparse.ArgumentParser(description="symmetric alignment builer")
# fmt: off
parser.add_argument('--fast_align_dir',
help='path to fast_align build directory')
parser.add_argument('--mosesdecoder_dir',
help='path to mosesdecoder root directory')
parser.add_argument('--sym_heuristic',
help='heuristic to use for symmetrization',
default='grow-diag-final-and')
parser.add_argument('--source_file',
help='path to a file with sentences '
'in the source language')
parser.add_argument('--target_file',
help='path to a file with sentences '
'in the target language')
parser.add_argument('--output_dir',
help='output directory')
# fmt: on
args = parser.parse_args()
fast_align_bin = os.path.join(args.fast_align_dir, "fast_align")
symal_bin = os.path.join(args.mosesdecoder_dir, "bin", "symal")
sym_fast_align_bin = os.path.join(
args.mosesdecoder_dir, "scripts", "ems", "support", "symmetrize-fast-align.perl"
)
# create joined file
joined_file = os.path.join(args.output_dir, "text.joined")
with open(args.source_file, "r", encoding="utf-8") as src, open(
args.target_file, "r", encoding="utf-8"
) as tgt:
with open(joined_file, "w", encoding="utf-8") as joined:
for s, t in zip_longest(src, tgt):
print("{} ||| {}".format(s.strip(), t.strip()), file=joined)
bwd_align_file = os.path.join(args.output_dir, "align.backward")
# run forward alignment
fwd_align_file = os.path.join(args.output_dir, "align.forward")
fwd_fast_align_cmd = "{FASTALIGN} -i {JOINED} -d -o -v > {FWD}".format(
FASTALIGN=fast_align_bin, JOINED=joined_file, FWD=fwd_align_file
)
assert os.system(fwd_fast_align_cmd) == 0
# run backward alignment
bwd_align_file = os.path.join(args.output_dir, "align.backward")
bwd_fast_align_cmd = "{FASTALIGN} -i {JOINED} -d -o -v -r > {BWD}".format(
FASTALIGN=fast_align_bin, JOINED=joined_file, BWD=bwd_align_file
)
assert os.system(bwd_fast_align_cmd) == 0
# run symmetrization
sym_out_file = os.path.join(args.output_dir, "aligned")
sym_cmd = "{SYMFASTALIGN} {FWD} {BWD} {SRC} {TGT} {OUT} {HEURISTIC} {SYMAL}".format(
SYMFASTALIGN=sym_fast_align_bin,
FWD=fwd_align_file,
BWD=bwd_align_file,
SRC=args.source_file,
TGT=args.target_file,
OUT=sym_out_file,
HEURISTIC=args.sym_heuristic,
SYMAL=symal_bin,
)
assert os.system(sym_cmd) == 0
if __name__ == "__main__":
main()