wehub-resource-sync
40 lines
1.1 KiB
Python
40 lines
1.1 KiB
Python
from typing import Optional
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import numpy as np
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from cleanlab.internal.constants import EPSILON
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def softmax(
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x: np.ndarray, temperature: float = 1.0, axis: Optional[int] = None, shift: bool = False
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) -> np.ndarray:
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"""Softmax function.
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Parameters
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----------
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x : np.ndarray
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Input array.
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temperature : float
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Temperature of the softmax function.
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axis : Optional[int]
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Axis to apply the softmax function. If None, the softmax function is
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applied to all elements of the input array.
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shift : bool
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Whether to shift the input array before applying the softmax function.
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This is useful to avoid numerical issues when the input array contains
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large values, that could result in overflows when applying the exponential
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function.
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Returns
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-------
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np.ndarray
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Softmax function applied to the input array.
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"""
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x = x / max(temperature, EPSILON)
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if shift:
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x = x - np.max(x, axis=axis, keepdims=True)
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exp_x = np.exp(x)
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return exp_x / np.sum(exp_x, axis=axis, keepdims=True)
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