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    Sigmoid function - Wikipedia

    A sigmoid function refers specifically to a function whose graph follows the logistic function. It is defined by the formula: $${\displaystyle \sigma (x)={\frac {1}{1+e^{-x}}}={\frac {e^{x}}{1+e^{x}}}=1-\sigma (-x).}$$In many fields, especially in the context of artificial neural networks, the term "sigmoid function" is correctly … 展开

    A sigmoid function is a bounded, differentiable, real function that is defined for all real input values and has a non-negative derivative at each point and exactly one 展开

    Applications 图像

    Many natural processes, such as those of complex system learning curves, exhibit a progression from small beginnings that accelerates and … 展开

    • Mitchell, Tom M. (1997). Machine Learning. WCB McGraw–Hill. ISBN 978-0-07-042807-2.. (NB. In particular see "Chapter 4: Artificial … 展开

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    Examples 图像

    In general, a sigmoid function is monotonic, and has a first derivative which is bell shaped. Conversely, the integral of any continuous, non-negative, bell-shaped function (with one local … 展开

    Logistic function $${\displaystyle f(x)={\frac {1}{1+e^{-x}}}}$$
    Hyperbolic tangent (shifted and scaled version of the logistic function, above) $${\displaystyle f(x)=\tanh x={\frac {e^{x}-e^{-x}}{e^{x}+e^{-x}}}}$$ 展开

    Step function – Linear combination of indicator functions of real intervals
    Sign function – Mathematical function returning -1, 0 or 1
    Heaviside step function – Indicator function of positive numbers 展开

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  2. Sigmoid函数 - 百度百科

  3. S型函数 - 维基百科,自由的百科全书

  4. 机器学习中的数学——激活函数(一):Sigmoid函数-C…

    2021年10月5日 · Sigmoid函数有时也称作逻辑函数或Logistic函数,是深度学习和神经网络中最初期使用的一种激活函数。其中,e是自然对数的底数(约等于2.71828),x是神经元的输入。Sigmoid函数的图形是一个S形的曲线,也被 …

  5. Sigmoid function详解 - 知乎 - 知乎专栏

  6. A Gentle Introduction To Sigmoid Function

    2021年8月18日 · Learn what is a sigmoid function, a special form of the logistic function that is used as an activation function in neural networks. Discover how the sigmoid function can produce non-linear decision boundaries and why it …

  7. 神经网络中的激活函数——Sigmoid函数 - CSDN博客

    2024年5月15日 · 本文介绍了Sigmoid函数的数学表达式函数图像和使用场景,以及它的优缺点。Sigmoid函数是一种常用的激活函数,可以将任意实数映射到0到1之间的值,适合二分类问题、逻辑回归、异常检测和概率建模等。

  8. Sigmoid Function – LearnDataSci

    A sigmoid function is a mathematical function with a characteristic "S"-shaped curve that transforms any value to a number between 0 and 1. Learn about its applications, issues, derivative, and graph with examples and code.

  9. Sigmoid Function -- from Wolfram MathWorld

    3 天之前 · Learn about the sigmoid function, also known as the logistic function, and its properties, derivatives, integrals, series, and differential equation. Explore the sigmoid function with Wolfram|Alpha and see …

  10. Sigmoid Function - an overview | ScienceDirect Topics