icefall/icefall/shared/convert-k2-to-openfst.py
zr_jin 6d275ddf9f
fixed broken softlinks (#1381)
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* fixed dependencies

* fixed file permission
2023-11-10 14:45:16 +08:00

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Python
Executable File

#!/usr/bin/env python3
# Copyright 2022 Xiaomi Corp. (authors: Fangjun Kuang)
#
# See ../../../../LICENSE for clarification regarding multiple authors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""
This script takes as input an FST in k2 format and convert it
to an FST in OpenFST format.
The generated FST is saved into a binary file and its type is
StdVectorFst.
Usage examples:
(1) Convert an acceptor
./convert-k2-to-openfst.py in.pt binary.fst
(2) Convert a transducer
./convert-k2-to-openfst.py --olabels aux_labels in.pt binary.fst
"""
import argparse
import logging
from pathlib import Path
import k2
import kaldifst.utils
import torch
def get_args():
parser = argparse.ArgumentParser()
parser.add_argument(
"--olabels",
type=str,
default=None,
help="""If not empty, the input FST is assumed to be a transducer
and we use its attribute specified by "olabels" as the output labels.
""",
)
parser.add_argument(
"input_filename",
type=str,
help="Path to the input FST in k2 format",
)
parser.add_argument(
"output_filename",
type=str,
help="Path to the output FST in OpenFst format",
)
return parser.parse_args()
def main():
args = get_args()
logging.info(f"{vars(args)}")
input_filename = args.input_filename
output_filename = args.output_filename
olabels = args.olabels
if Path(output_filename).is_file():
logging.info(f"{output_filename} already exists - skipping")
return
assert Path(input_filename).is_file(), f"{input_filename} does not exist"
logging.info(f"Loading {input_filename}")
k2_fst = k2.Fsa.from_dict(torch.load(input_filename))
if olabels:
assert hasattr(k2_fst, olabels), f"No such attribute: {olabels}"
p = Path(output_filename).parent
if not p.is_dir():
logging.info(f"Creating {p}")
p.mkdir(parents=True)
logging.info("Converting (May take some time if the input FST is large)")
fst = kaldifst.utils.k2_to_openfst(k2_fst, olabels=olabels)
logging.info(f"Saving to {output_filename}")
fst.write(output_filename)
if __name__ == "__main__":
formatter = "%(asctime)s %(levelname)s [%(filename)s:%(lineno)d] %(message)s"
logging.basicConfig(format=formatter, level=logging.INFO)
main()