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hover.utils.snorkel_helper

  • labeling_function(targets, label_encoder=None, **kwargs)

    Hover's flavor of the Snorkel labeling_function decorator.

    However, due to the dynamic label encoding nature of hover, the decorated function should return the original string label, not its encoding integer.

    • assigns a UUID for easy identification
    • keeps track of LF targets
    Param Type Description
    targets list of str labels that the labeling function is intended to create
    label_encoder dict {decoded_label -> encoded_label} mapping, if you also want an original snorkel-style labeling function linked as a .snorkel attribute
    **kwargs forwarded to snorkel's labeling_function()
    Source code in hover/utils/snorkel_helper.py
    def labeling_function(targets, label_encoder=None, **kwargs):
        """
        ???+ note "Hover's flavor of the Snorkel labeling_function decorator."
            However, due to the dynamic label encoding nature of hover,
            the decorated function should return the original string label, not its encoding integer.
    
            - assigns a UUID for easy identification
            - keeps track of LF targets
    
            | Param           | Type   | Description                          |
            | :-------------- | :----- | :----------------------------------- |
            | `targets`       | `list` of `str` | labels that the labeling function is intended to create |
            | `label_encoder` | `dict` | {decoded_label -> encoded_label} mapping, if you also want an original snorkel-style labeling function linked as a `.snorkel` attribute |
            | `**kwargs`      |        | forwarded to `snorkel`'s `labeling_function()` |
        """
        # lazy import of optional dependency
        from snorkel.labeling import (
            labeling_function as snorkel_lf,
            LabelingFunction as SnorkelLF,
        )
    
        def wrapper(func):
            # set up kwargs for Snorkel's LF
            snorkel_kwargs = {"name": func.__name__}
            snorkel_kwargs.update(kwargs)
    
            # return value of hover's decorator
            lf = SnorkelLF(f=func, **snorkel_kwargs)
    
            # additional attributes
            lf.uuid = uuid.uuid1()
            lf.targets = targets[:]
    
            # link a snorkel-style labeling function if applicable
            if label_encoder:
                lf.label_encoder = label_encoder
    
                def snorkel_style_func(x):
                    return lf.label_encoder[func(x)]
    
                lf.snorkel = snorkel_lf(**kwargs)(snorkel_style_func)
            else:
                lf.label_encoder = None
                lf.snorkel = None
    
            return lf
    
        return wrapper