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There was a grouping I saw once of functions that are similar to atan2 where the Y result can only ever be below 1 and over -1 and the closer the value is to the maximum or minimum the longer it takes to reach it on the X axis (until infinity).

Does anyone know the name of these functions?

atan2

dimiguel
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1 Answers1

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Such functions are called sigmoid. Differentiable everywhere with non-negative derivative, bounded.

vonbrand
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  • This is exactly it, thank you! – dimiguel Aug 06 '19 at 22:20
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    Since "sigmoid" means "S-shaped", you probably also want a require a sigmoid function to be convex at first and then change to concave (exactly once, not back and forth between convex and concave). – Hans Lundmark Aug 07 '19 at 08:10