e1071 (version 1.1-0)

sigmoid: The logistic function and derivatives

Description

Sigmoid $1/(1 + exp(-x))$, first and second derivative.

Usage

sigmoid(x)
dsigmoid(x)
d2sigmoid(x)

Examples

plot(sigmoid, -5, 5, ylim=c(-.2, 1))
plot(dsigmoid, -5, 5, add=T, col=2)
plot(d2sigmoid, -5, 5, add=T, col=3)