R: The Logistic Function and Derivatives

sigmoid {e1071} | R Documentation

## The Logistic Function and Derivatives

### Description

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

### Usage

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

### Arguments

`x` | a numeric vector

### Author(s)

Friedrich Leisch

### Examples

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

[Package e1071 version 1.7-4 Index]