epfml / ML_course

EPFL Machine Learning Course, Fall 2024
https://www.epfl.ch/labs/mlo/machine-learning-cs-433/
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Typo in formulation of sigmoid function #49

Open MaximeKjaer opened 5 years ago

MaximeKjaer commented 5 years ago

Lecture 5b page 2 defines the logistic function as e^z / (1+e^z). This formulation is equivalent to 1/(1+e^(-z)), or 1 - 1/(1 + e^z).

Lecture 12a page 5 says that the sigmoid function 1/(1+e^(-x)) is one minus the logistic function, which is contradictory to lecture 5b.

Wikipedia's definition of the sigmoid function seems to say that the sigmoid function and logistic function often are referred to interchangeably. Therefore, I believe that saying that the sigmoid is one minus the logistic is wrong.