34 lines
1.4 KiB
Python
34 lines
1.4 KiB
Python
from operator import itemgetter
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from typing import Mapping, Iterable
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import numpy as np
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from funcy import rcompose, rpartial
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from image_prediction.exceptions import UnexpectedLabelFormat
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from image_prediction.label_mapper.mapper import LabelMapper
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class ProbabilityMapper(LabelMapper):
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def __init__(self, labels: Mapping[int, str]):
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self.__labels = labels
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# String conversion in the middle due to floating point precision issues.
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# See: https://stackoverflow.com/questions/56820/round-doesnt-seem-to-be-rounding-properly
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self.__rounder = rcompose(rpartial(round, 4), str, float)
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def __validate_array_label_format(self, probabilities: np.ndarray) -> None:
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if not len(probabilities) == len(self.__labels):
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raise UnexpectedLabelFormat(
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f"Received fewer probabilities ({len(probabilities)}) than labels were passed ({len(self.__labels)})."
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)
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def __map_array(self, probabilities: np.ndarray) -> dict:
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self.__validate_array_label_format(probabilities)
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cls2prob = dict(
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sorted(zip(self.__labels, list(map(self.__rounder, probabilities))), key=itemgetter(1), reverse=True)
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)
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most_likely = [*cls2prob][0]
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return {"label": most_likely, "probabilities": cls2prob}
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def map_labels(self, probabilities: Iterable[np.ndarray]) -> Iterable[dict]:
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return map(self.__map_array, probabilities)
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