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    yi                     @   s\   d dl mZmZmZ d dlZd dlmZmZ d dlmZm	Z	 d dl
mZ G dd deZdS )    )AnyListUnionN)Tensortensor)_wer_compute_wer_update)Metricc                       s   e Zd ZU dZdZeed< dZeed< dZeed< e	ed< e	ed< de
f fd	d
Zdeeee f deeee f ddfddZde	fddZ  ZS )WordErrorRatea  Word error rate (`WordErrorRate`_) is a common metric of the performance of an automatic speech recognition
    system. This value indicates the percentage of words that were incorrectly predicted. The lower the value, the
    better the performance of the ASR system with a WER of 0 being a perfect score. Word error rate can then be
    computed as:

    .. math::
        WER = \frac{S + D + I}{N} = \frac{S + D + I}{S + D + C}

    where:
    - :math:`S` is the number of substitutions,
    - :math:`D` is the number of deletions,
    - :math:`I` is the number of insertions,
    - :math:`C` is the number of correct words,
    - :math:`N` is the number of words in the reference (:math:`N=S+D+C`).

    Compute WER score of transcribed segments against references.

    As input to ``forward`` and ``update`` the metric accepts the following input:

    - ``preds`` (:class:`~List`): Transcription(s) to score as a string or list of strings
    - ``target`` (:class:`~List`): Reference(s) for each speech input as a string or list of strings

    As output of ``forward`` and ``compute`` the metric returns the following output:

    -  ``wer`` (:class:`~torch.Tensor`): A tensor with the Word Error Rate score

    Args:
        kwargs: Additional keyword arguments, see :ref:`Metric kwargs` for more info.

    Examples:
        >>> preds = ["this is the prediction", "there is an other sample"]
        >>> target = ["this is the reference", "there is another one"]
        >>> wer = WordErrorRate()
        >>> wer(preds, target)
        tensor(0.5000)
    Fis_differentiablehigher_is_betterfull_state_updateerrorstotalkwargsc                    sJ   t  jdi | | jdtdtjddd | jdtdtjddd d S )Nr   r   )dtypesum)dist_reduce_fxr    )super__init__	add_stater   torchfloat)selfr   	__class__r   I/home/ubuntu/.local/lib/python3.10/site-packages/torchmetrics/text/wer.pyr   C   s   zWordErrorRate.__init__predstargetreturnNc                 C   s.   t ||\}}|  j|7  _|  j|7  _dS )z*Update state with predictions and targets.N)r   r   r   )r   r   r   r   r   r   r   r   updateK   s   zWordErrorRate.updatec                 C   s   t | j| jS )zCalculate the word error rate.)r   r   r   )r   r   r   r   computeQ   s   zWordErrorRate.compute)__name__
__module____qualname____doc__r   bool__annotations__r   r   r   r   r   r   strr   r!   r"   __classcell__r   r   r   r   r
      s   
 $.r
   )typingr   r   r   r   r   r    torchmetrics.functional.text.werr   r   torchmetrics.metricr	   r
   r   r   r   r   <module>   s   