Add fast_beam_search_LG (#622)

* Add fast_beam_search_LG

* add fast_beam_search_LG to commonly used recipes

* fix ci

* fix ci

* Fix error

.github/scripts/run-librispeech-pruned-transducer-stateless2-2022-04-29.sh

@@ -83,4 +83,5 @@ if [[ x"${GITHUB_EVENT_NAME}" == x"schedule" || x"${GITHUB_EVENT_LABEL_NAME}" ==
   done
 
   rm pruned_transducer_stateless2/exp/*.pt
+  rm -r data/lang_bpe_500
 fi

.github/scripts/run-librispeech-pruned-transducer-stateless3-2022-04-29.sh

@@ -82,4 +82,5 @@ if [[ x"${GITHUB_EVENT_NAME}" == x"schedule" || x"${GITHUB_EVENT_LABEL_NAME}" ==
   done
 
   rm pruned_transducer_stateless3/exp/*.pt
+  rm -r data/lang_bpe_500
 fi

egs/librispeech/ASR/pruned_transducer_stateless/decode.py

@@ -206,6 +206,7 @@ def get_parser():
           - beam_search
           - modified_beam_search
           - fast_beam_search
+          - fast_beam_search_LG
           - fast_beam_search_nbest
           - fast_beam_search_nbest_oracle
           - fast_beam_search_nbest_LG
@@ -230,7 +231,7 @@ def get_parser():
         help="""A floating point value to calculate the cutoff score during beam
         search (i.e., `cutoff = max-score - beam`), which is the same as the
         `beam` in Kaldi.
-        Used only when --decoding-method is fast_beam_search,
+        Used only when --decoding-method is fast_beam_search, fast_beam_search_LG
         fast_beam_search_nbest, fast_beam_search_nbest_LG,
         and fast_beam_search_nbest_oracle
         """,
@@ -241,7 +242,7 @@ def get_parser():
         type=float,
         default=0.01,
         help="""
-        Used only when --decoding_method is fast_beam_search_nbest_LG.
+        Used only when --decoding_method is fast_beam_search_nbest_LG and fast_beam_search_LG.
         It specifies the scale for n-gram LM scores.
         """,
     )
@@ -250,7 +251,7 @@ def get_parser():
         "--max-contexts",
         type=int,
         default=8,
-        help="""Used only when --decoding-method is
+        help="""Used only when --decoding-method is fast_beam_search_LG
         fast_beam_search, fast_beam_search_nbest, fast_beam_search_nbest_LG,
         and fast_beam_search_nbest_oracle""",
     )
@@ -259,7 +260,7 @@ def get_parser():
         "--max-states",
         type=int,
         default=8,
-        help="""Used only when --decoding-method is
+        help="""Used only when --decoding-method is fast_beam_search_LG
         fast_beam_search, fast_beam_search_nbest, fast_beam_search_nbest_LG,
         and fast_beam_search_nbest_oracle""",
     )
@@ -355,8 +356,8 @@ def decode_one_batch(
       word_table:
         The word symbol table.
       decoding_graph:
-        The decoding graph. Can be either a `k2.trivial_graph` or HLG, Used
+        The decoding graph. Can be either a `k2.trivial_graph` or LG, Used
-        only when --decoding_method is fast_beam_search, fast_beam_search_nbest,
+        only when --decoding_method is fast_beam_search, fast_beam_search_LG, fast_beam_search_nbest,
         fast_beam_search_nbest_oracle, and fast_beam_search_nbest_LG.
     Returns:
       Return the decoding result. See above description for the format of
@@ -387,7 +388,10 @@ def decode_one_batch(
         )
     hyps = []
 
-    if params.decoding_method == "fast_beam_search":
+    if (
+        params.decoding_method == "fast_beam_search"
+        or params.decoding_method == "fast_beam_search_LG"
+    ):
         hyp_tokens = fast_beam_search_one_best(
             model=model,
             decoding_graph=decoding_graph,
@@ -397,8 +401,12 @@ def decode_one_batch(
             max_contexts=params.max_contexts,
             max_states=params.max_states,
         )
-        for hyp in sp.decode(hyp_tokens):
+        if params.decoding_method == "fast_beam_search":
-            hyps.append(hyp.split())
+            for hyp in sp.decode(hyp_tokens):
+                hyps.append(hyp.split())
+        else:
+            for hyp in hyp_tokens:
+                hyps.append([word_table[i] for i in hyp])
     elif params.decoding_method == "fast_beam_search_nbest_LG":
         hyp_tokens = fast_beam_search_nbest_LG(
             model=model,
@@ -526,8 +534,8 @@ def decode_dataset(
       word_table:
         The word symbol table.
       decoding_graph:
-        The decoding graph. Can be either a `k2.trivial_graph` or HLG, Used
+        The decoding graph. Can be either a `k2.trivial_graph` or LG, Used
-        only when --decoding_method is fast_beam_search, fast_beam_search_nbest,
+        only when --decoding_method is fast_beam_search, fast_beam_search_LG, fast_beam_search_nbest,
         fast_beam_search_nbest_oracle, and fast_beam_search_nbest_LG.
     Returns:
       Return a dict, whose key may be "greedy_search" if greedy search
@@ -643,6 +651,7 @@ def main():
         "greedy_search",
         "beam_search",
         "fast_beam_search",
+        "fast_beam_search_LG",
         "fast_beam_search_nbest",
         "fast_beam_search_nbest_LG",
         "fast_beam_search_nbest_oracle",
@@ -737,7 +746,7 @@ def main():
     model.device = device
 
     if "fast_beam_search" in params.decoding_method:
-        if params.decoding_method == "fast_beam_search_nbest_LG":
+        if "LG" in params.decoding_method:
             lexicon = Lexicon(params.lang_dir)
             word_table = lexicon.word_table
             lg_filename = params.lang_dir / "LG.pt"

egs/librispeech/ASR/pruned_transducer_stateless2/beam_search.py

@@ -15,7 +15,7 @@
 # limitations under the License.
 
 import warnings
-from dataclasses import dataclass
+from dataclasses import dataclass, field
 from typing import Dict, List, Optional, Union
 
 import k2
@@ -727,7 +727,7 @@ class Hypothesis:
 
     # timestamp[i] is the frame index after subsampling
     # on which ys[i] is decoded
-    timestamp: List[int]
+    timestamp: List[int] = field(default_factory=list)
 
     state_cost: Optional[NgramLmStateCost] = None
 

egs/librispeech/ASR/pruned_transducer_stateless2/decode.py

@@ -212,6 +212,7 @@ def get_parser():
           - beam_search
           - modified_beam_search
           - fast_beam_search
+          - fast_beam_search_LG
           - fast_beam_search_nbest
           - fast_beam_search_nbest_oracle
           - fast_beam_search_nbest_LG
@@ -247,8 +248,8 @@ def get_parser():
         type=float,
         default=0.01,
         help="""
-        Used only when --decoding_method is fast_beam_search_nbest_LG.
+        Used only when --decoding_method is fast_beam_search_LG and
-        It specifies the scale for n-gram LM scores.
+        fast_beam_search_nbest_LG. It specifies the scale for n-gram LM scores.
         """,
     )
 
@@ -256,7 +257,7 @@ def get_parser():
         "--max-contexts",
         type=int,
         default=8,
-        help="""Used only when --decoding-method is
+        help="""Used only when --decoding-method is fast_beam_search_LG
         fast_beam_search, fast_beam_search_nbest, fast_beam_search_nbest_LG,
         and fast_beam_search_nbest_oracle""",
     )
@@ -265,7 +266,7 @@ def get_parser():
         "--max-states",
         type=int,
         default=64,
-        help="""Used only when --decoding-method is
+        help="""Used only when --decoding-method is fast_beam_search_LG
         fast_beam_search, fast_beam_search_nbest, fast_beam_search_nbest_LG,
         and fast_beam_search_nbest_oracle""",
     )
@@ -363,9 +364,10 @@ def decode_one_batch(
       word_table:
         The word symbol table.
       decoding_graph:
-        The decoding graph. Can be either a `k2.trivial_graph` or HLG, Used
+        The decoding graph. Can be either a `k2.trivial_graph` or LG, Used
-        only when --decoding_method is fast_beam_search, fast_beam_search_nbest,
+        only when --decoding_method is fast_beam_search, fast_beam_search_LG,
-        fast_beam_search_nbest_oracle, and fast_beam_search_nbest_LG.
+        fast_beam_search_nbest, fast_beam_search_nbest_oracle, and
+        fast_beam_search_nbest_LG.
     Returns:
       Return the decoding result. See above description for the format of
       the returned dict.
@@ -401,7 +403,10 @@ def decode_one_batch(
 
     hyps = []
 
-    if params.decoding_method == "fast_beam_search":
+    if (
+        params.decoding_method == "fast_beam_search"
+        or params.decoding_method == "fast_beam_search_LG"
+    ):
         hyp_tokens = fast_beam_search_one_best(
             model=model,
             decoding_graph=decoding_graph,
@@ -411,8 +416,12 @@ def decode_one_batch(
             max_contexts=params.max_contexts,
             max_states=params.max_states,
         )
-        for hyp in sp.decode(hyp_tokens):
+        if params.decoding_method == "fast_beam_search":
-            hyps.append(hyp.split())
+            for hyp in sp.decode(hyp_tokens):
+                hyps.append(hyp.split())
+        else:
+            for hyp in hyp_tokens:
+                hyps.append([word_table[i] for i in hyp])
     elif params.decoding_method == "fast_beam_search_nbest_LG":
         hyp_tokens = fast_beam_search_nbest_LG(
             model=model,
@@ -548,9 +557,10 @@ def decode_dataset(
       word_table:
         The word symbol table.
       decoding_graph:
-        The decoding graph. Can be either a `k2.trivial_graph` or HLG, Used
+        The decoding graph. Can be either a `k2.trivial_graph` or LG, Used
-        only when --decoding_method is fast_beam_search, fast_beam_search_nbest,
+        only when --decoding_method is fast_beam_search, fast_beam_search_LG,
-        fast_beam_search_nbest_oracle, and fast_beam_search_nbest_LG.
+        fast_beam_search_nbest, fast_beam_search_nbest_oracle, and
+        fast_beam_search_nbest_LG.
     Returns:
       Return a dict, whose key may be "greedy_search" if greedy search
       is used, or it may be "beam_7" if beam size of 7 is used.
@@ -663,6 +673,7 @@ def main():
         "greedy_search",
         "beam_search",
         "fast_beam_search",
+        "fast_beam_search_LG",
         "fast_beam_search_nbest",
         "fast_beam_search_nbest_LG",
         "fast_beam_search_nbest_oracle",
@@ -757,7 +768,7 @@ def main():
     model.device = device
 
     if "fast_beam_search" in params.decoding_method:
-        if params.decoding_method == "fast_beam_search_nbest_LG":
+        if "LG" in params.decoding_method:
             lexicon = Lexicon(params.lang_dir)
             word_table = lexicon.word_table
             lg_filename = params.lang_dir / "LG.pt"

egs/librispeech/ASR/pruned_transducer_stateless3/decode.py

@@ -202,6 +202,7 @@ def get_parser():
           - beam_search
           - modified_beam_search
           - fast_beam_search
+          - fast_beam_search_LG
           - fast_beam_search_nbest
           - fast_beam_search_nbest_oracle
           - fast_beam_search_nbest_LG
@@ -226,7 +227,7 @@ def get_parser():
         help="""A floating point value to calculate the cutoff score during beam
         search (i.e., `cutoff = max-score - beam`), which is the same as the
         `beam` in Kaldi.
-        Used only when --decoding-method is fast_beam_search,
+        Used only when --decoding-method is fast_beam_search, fast_beam_search_LG,
         fast_beam_search_nbest, fast_beam_search_nbest_LG,
         and fast_beam_search_nbest_oracle
         """,
@@ -237,7 +238,7 @@ def get_parser():
         type=float,
         default=0.01,
         help="""
-        Used only when --decoding_method is fast_beam_search_nbest_LG.
+        Used only when --decoding_method is fast_beam_search_nbest_LG and fast_beam_search_LG.
         It specifies the scale for n-gram LM scores.
         """,
     )
@@ -246,7 +247,7 @@ def get_parser():
         "--max-contexts",
         type=int,
         default=8,
-        help="""Used only when --decoding-method is
+        help="""Used only when --decoding-method is fast_beam_search_LG,
         fast_beam_search, fast_beam_search_nbest, fast_beam_search_nbest_LG,
         and fast_beam_search_nbest_oracle""",
     )
@@ -255,7 +256,7 @@ def get_parser():
         "--max-states",
         type=int,
         default=64,
-        help="""Used only when --decoding-method is
+        help="""Used only when --decoding-method is, fast_beam_search_LG,
         fast_beam_search, fast_beam_search_nbest, fast_beam_search_nbest_LG,
         and fast_beam_search_nbest_oracle""",
     )
@@ -440,8 +441,8 @@ def decode_one_batch(
       word_table:
         The word symbol table.
       decoding_graph:
-        The decoding graph. Can be either a `k2.trivial_graph` or HLG, Used
+        The decoding graph. Can be either a `k2.trivial_graph` or LG, Used
-        only when --decoding_method is fast_beam_search, fast_beam_search_nbest,
+        only when --decoding_method is fast_beam_search, fast_beam_search_LG, fast_beam_search_nbest,
         fast_beam_search_nbest_oracle, and fast_beam_search_nbest_LG.
       G:
         Optional. Used only when decoding method is fast_beam_search,
@@ -483,7 +484,10 @@ def decode_one_batch(
 
     hyps = []
 
-    if params.decoding_method == "fast_beam_search":
+    if (
+        params.decoding_method == "fast_beam_search"
+        or params.decoding_method == "fast_beam_search_LG"
+    ):
         hyp_tokens = fast_beam_search_one_best(
             model=model,
             decoding_graph=decoding_graph,
@@ -494,8 +498,12 @@ def decode_one_batch(
             max_states=params.max_states,
             temperature=params.temperature,
         )
-        for hyp in sp.decode(hyp_tokens):
+        if params.decoding_method == "fast_beam_search":
-            hyps.append(hyp.split())
+            for hyp in sp.decode(hyp_tokens):
+                hyps.append(hyp.split())
+        else:
+            for hyp in hyp_tokens:
+                hyps.append([word_table[i] for i in hyp])
     elif params.decoding_method == "fast_beam_search_nbest_LG":
         hyp_tokens = fast_beam_search_nbest_LG(
             model=model,
@@ -714,8 +722,8 @@ def decode_dataset(
       word_table:
         The word symbol table.
       decoding_graph:
-        The decoding graph. Can be either a `k2.trivial_graph` or HLG, Used
+        The decoding graph. Can be either a `k2.trivial_graph` or LG, Used
-        only when --decoding_method is fast_beam_search, fast_beam_search_nbest,
+        only when --decoding_method is fast_beam_search, fast_beam_search_LG, fast_beam_search_nbest,
         fast_beam_search_nbest_oracle, and fast_beam_search_nbest_LG.
       G:
         Optional. Used only when decoding method is fast_beam_search,
@@ -901,6 +909,7 @@ def main():
         "greedy_search",
         "beam_search",
         "fast_beam_search",
+        "fast_beam_search_LG",
         "fast_beam_search_nbest",
         "fast_beam_search_nbest_LG",
         "fast_beam_search_nbest_oracle",
@@ -1002,7 +1011,7 @@ def main():
 
     G = None
     if "fast_beam_search" in params.decoding_method:
-        if params.decoding_method == "fast_beam_search_nbest_LG":
+        if "LG" in params.decoding_method:
             lexicon = Lexicon(params.lang_dir)
             word_table = lexicon.word_table
             lg_filename = params.lang_dir / "LG.pt"

egs/librispeech/ASR/pruned_transducer_stateless4/decode.py

@@ -243,6 +243,7 @@ def get_parser():
           - beam_search
           - modified_beam_search
           - fast_beam_search
+          - fast_beam_search_LG
           - fast_beam_search_nbest
           - fast_beam_search_nbest_oracle
           - fast_beam_search_nbest_LG
@@ -267,7 +268,7 @@ def get_parser():
         help="""A floating point value to calculate the cutoff score during beam
         search (i.e., `cutoff = max-score - beam`), which is the same as the
         `beam` in Kaldi.
-        Used only when --decoding-method is fast_beam_search,
+        Used only when --decoding-method is fast_beam_search, fast_beam_search_LG,
         fast_beam_search_nbest, fast_beam_search_nbest_LG,
         and fast_beam_search_nbest_oracle
         """,
@@ -278,7 +279,7 @@ def get_parser():
         type=float,
         default=0.01,
         help="""
-        Used only when --decoding_method is fast_beam_search_nbest_LG.
+        Used only when --decoding_method is fast_beam_search_nbest_LG and fast_beam_search_LG.
         It specifies the scale for n-gram LM scores.
         """,
     )
@@ -287,7 +288,7 @@ def get_parser():
         "--max-contexts",
         type=int,
         default=8,
-        help="""Used only when --decoding-method is
+        help="""Used only when --decoding-method is fast_beam_search_LG,
         fast_beam_search, fast_beam_search_nbest, fast_beam_search_nbest_LG,
         and fast_beam_search_nbest_oracle""",
     )
@@ -296,7 +297,7 @@ def get_parser():
         "--max-states",
         type=int,
         default=64,
-        help="""Used only when --decoding-method is
+        help="""Used only when --decoding-method is fast_beam_search_LG,
         fast_beam_search, fast_beam_search_nbest, fast_beam_search_nbest_LG,
         and fast_beam_search_nbest_oracle""",
     )
@@ -394,8 +395,8 @@ def decode_one_batch(
       word_table:
         The word symbol table.
       decoding_graph:
-        The decoding graph. Can be either a `k2.trivial_graph` or HLG, Used
+        The decoding graph. Can be either a `k2.trivial_graph` or LG, Used
-        only when --decoding_method is fast_beam_search, fast_beam_search_nbest,
+        only when --decoding_method is fast_beam_search, fast_beam_search_LG, fast_beam_search_nbest,
         fast_beam_search_nbest_oracle, and fast_beam_search_nbest_LG.
     Returns:
       Return the decoding result and timestamps. See above description for the
@@ -430,7 +431,10 @@ def decode_one_batch(
             x=feature, x_lens=feature_lens
         )
 
-    if params.decoding_method == "fast_beam_search":
+    if (
+        params.decoding_method == "fast_beam_search"
+        or params.decoding_method == "fast_beam_search_LG"
+    ):
         res = fast_beam_search_one_best(
             model=model,
             decoding_graph=decoding_graph,
@@ -579,8 +583,8 @@ def decode_dataset(
       word_table:
         The word symbol table.
       decoding_graph:
-        The decoding graph. Can be either a `k2.trivial_graph` or HLG, Used
+        The decoding graph. Can be either a `k2.trivial_graph` or LG, Used
-        only when --decoding_method is fast_beam_search, fast_beam_search_nbest,
+        only when --decoding_method is fast_beam_search, fast_beam_search_LG, fast_beam_search_nbest,
         fast_beam_search_nbest_oracle, and fast_beam_search_nbest_LG.
     Returns:
       Return a dict, whose key may be "greedy_search" if greedy search
@@ -742,6 +746,7 @@ def main():
         "greedy_search",
         "beam_search",
         "fast_beam_search",
+        "fast_beam_search_LG",
         "fast_beam_search_nbest",
         "fast_beam_search_nbest_LG",
         "fast_beam_search_nbest_oracle",
@@ -886,7 +891,7 @@ def main():
     model.eval()
 
     if "fast_beam_search" in params.decoding_method:
-        if params.decoding_method == "fast_beam_search_nbest_LG":
+        if "LG" in params.decoding_method:
             lexicon = Lexicon(params.lang_dir)
             word_table = lexicon.word_table
             lg_filename = params.lang_dir / "LG.pt"

egs/librispeech/ASR/pruned_transducer_stateless5/decode.py

@@ -210,6 +210,7 @@ def get_parser():
           - beam_search
           - modified_beam_search
           - fast_beam_search
+          - fast_beam_search_LG
           - fast_beam_search_nbest
           - fast_beam_search_nbest_oracle
           - fast_beam_search_nbest_LG
@@ -234,7 +235,7 @@ def get_parser():
         help="""A floating point value to calculate the cutoff score during beam
         search (i.e., `cutoff = max-score - beam`), which is the same as the
         `beam` in Kaldi.
-        Used only when --decoding-method is fast_beam_search,
+        Used only when --decoding-method is fast_beam_search, fast_beam_search_LG,
         fast_beam_search_nbest, fast_beam_search_nbest_LG,
         and fast_beam_search_nbest_oracle
         """,
@@ -245,7 +246,7 @@ def get_parser():
         type=float,
         default=0.01,
         help="""
-        Used only when --decoding_method is fast_beam_search_nbest_LG.
+        Used only when --decoding_method is fast_beam_search_nbest_LG and fast_beam_search_LG.
         It specifies the scale for n-gram LM scores.
         """,
     )
@@ -254,7 +255,7 @@ def get_parser():
         "--max-contexts",
         type=int,
         default=8,
-        help="""Used only when --decoding-method is
+        help="""Used only when --decoding-method is fast_beam_search_LG,
         fast_beam_search, fast_beam_search_nbest, fast_beam_search_nbest_LG,
         and fast_beam_search_nbest_oracle""",
     )
@@ -263,7 +264,7 @@ def get_parser():
         "--max-states",
         type=int,
         default=64,
-        help="""Used only when --decoding-method is
+        help="""Used only when --decoding-method is fast_beam_search_LG,
         fast_beam_search, fast_beam_search_nbest, fast_beam_search_nbest_LG,
         and fast_beam_search_nbest_oracle""",
     )
@@ -361,8 +362,8 @@ def decode_one_batch(
       word_table:
         The word symbol table.
       decoding_graph:
-        The decoding graph. Can be either a `k2.trivial_graph` or HLG, Used
+        The decoding graph. Can be either a `k2.trivial_graph` or LG, Used
-        only when --decoding_method is fast_beam_search, fast_beam_search_nbest,
+        only when --decoding_method is fast_beam_search, fast_beam_search_LG, fast_beam_search_nbest,
         fast_beam_search_nbest_oracle, and fast_beam_search_nbest_LG.
     Returns:
       Return the decoding result. See above description for the format of
@@ -399,7 +400,10 @@ def decode_one_batch(
 
     hyps = []
 
-    if params.decoding_method == "fast_beam_search":
+    if (
+        params.decoding_method == "fast_beam_search"
+        or params.decoding_method == "fast_beam_search_LG"
+    ):
         hyp_tokens = fast_beam_search_one_best(
             model=model,
             decoding_graph=decoding_graph,
@@ -409,8 +413,12 @@ def decode_one_batch(
             max_contexts=params.max_contexts,
             max_states=params.max_states,
         )
-        for hyp in sp.decode(hyp_tokens):
+        if params.decoding_method == "fast_beam_search":
-            hyps.append(hyp.split())
+            for hyp in sp.decode(hyp_tokens):
+                hyps.append(hyp.split())
+        else:
+            for hyp in hyp_tokens:
+                hyps.append([word_table[i] for i in hyp])
     elif params.decoding_method == "fast_beam_search_nbest_LG":
         hyp_tokens = fast_beam_search_nbest_LG(
             model=model,
@@ -538,8 +546,8 @@ def decode_dataset(
       word_table:
         The word symbol table.
       decoding_graph:
-        The decoding graph. Can be either a `k2.trivial_graph` or HLG, Used
+        The decoding graph. Can be either a `k2.trivial_graph` or LG, Used
-        only when --decoding_method is fast_beam_search, fast_beam_search_nbest,
+        only when --decoding_method is fast_beam_search, fast_beam_search_LG, fast_beam_search_nbest,
         fast_beam_search_nbest_oracle, and fast_beam_search_nbest_LG.
     Returns:
       Return a dict, whose key may be "greedy_search" if greedy search
@@ -653,6 +661,7 @@ def main():
         "greedy_search",
         "beam_search",
         "fast_beam_search",
+        "fast_beam_search_LG",
         "fast_beam_search_nbest",
         "fast_beam_search_nbest_LG",
         "fast_beam_search_nbest_oracle",
@@ -797,7 +806,7 @@ def main():
     model.eval()
 
     if "fast_beam_search" in params.decoding_method:
-        if params.decoding_method == "fast_beam_search_nbest_LG":
+        if "LG" in params.decoding_method:
             lexicon = Lexicon(params.lang_dir)
             word_table = lexicon.word_table
             lg_filename = params.lang_dir / "LG.pt"

icefall/utils.py

@@ -1369,6 +1369,7 @@ def parse_hyp_and_timestamp(
           - beam_search
           - modified_beam_search
           - fast_beam_search
+          - fast_beam_search_LG
           - fast_beam_search_nbest
           - fast_beam_search_nbest_oracle
           - fast_beam_search_nbest_LG
@@ -1388,6 +1389,7 @@ def parse_hyp_and_timestamp(
         "greedy_search",
         "beam_search",
         "fast_beam_search",
+        "fast_beam_search_LG",
         "fast_beam_search_nbest",
         "fast_beam_search_nbest_LG",
         "fast_beam_search_nbest_oracle",
@@ -1400,7 +1402,10 @@ def parse_hyp_and_timestamp(
     N = len(res.tokens)
     assert len(res.timestamps) == N
     use_word_table = False
-    if decoding_method == "fast_beam_search_nbest_LG":
+    if (
+        decoding_method == "fast_beam_search_nbest_LG"
+        and decoding_method == "fast_beam_search_LG"
+    ):
         assert word_table is not None
         use_word_table = True