Adding blank penalty

[chiiyeh]

Hi, I am interested to know if blank_penalty can be added as a parameter, given that it seems useful for reducing deletions error in some cases like k2-fsa/icefall#1130 (comment)?

[Triplecq]

Hi,

I could easily be wrong, but I think you can refer to this recipe: https://github.com/k2-fsa/icefall/blob/master/egs/aishell/ASR/zipformer/decode.py

1. add this new parameter at line 289 as follows:

 parser.add_argument(
        "--blank-penalty",
        type=float,
        default=0.0,
        help="""
        The penalty applied on blank symbol during decoding.
        Note: It is a positive value that would be applied to logits like
        this `logits[:, 0] -= blank_penalty` (suppose logits.shape is
        [batch_size, vocab] and blank id is 0).
        """,
    )

2. feed this new parameter to each decoding method, e.g. line 380:

blank_penalty=params.blank_penalty,

I hope it helps!

[csukuangfj]

Hi,

I could easily be wrong, but I think you can refer to this recipe: https://github.com/k2-fsa/icefall/blob/master/egs/aishell/ASR/zipformer/decode.py

1. add this new parameter at line 289 as follows:

 parser.add_argument(
        "--blank-penalty",
        type=float,
        default=0.0,
        help="""
        The penalty applied on blank symbol during decoding.
        Note: It is a positive value that would be applied to logits like
        this `logits[:, 0] -= blank_penalty` (suppose logits.shape is
        [batch_size, vocab] and blank id is 0).
        """,
    )

2. feed this new parameter to each decoding method, e.g. line 380:

blank_penalty=params.blank_penalty,

I hope it helps!

I think you are right, though it is in Python.

Similar code can be added to C++ in sherpa-onnx.

Is anyone willing to contribute? We could provide help with it.

[chiiyeh]

I can try to add it in!

[csukuangfj]

I can try to add it in!

Thanks! Feel free to leave a message when you have any issues.