logisticShift: Univariate logistic function

In adamlilith/enmSdmPredImport: Testing measures of predictor importance in species distribution models

Univariate logistic function

Description

The univariate logistic function. A variant of logistic, it returns logistic output in response to one or two variables, but includes an additional term for "shifting" the response to the "left" or "right" along x1.

Usage

logisticShift(x1, b0 = 0, b1 = 1, b11 = 0, ...)

Arguments

x1	Numeric, first variable.
b0	Numeric, intercept. Default is 0.
b1	Numeric, slope with respect to x1. Default is 1.
b11	Numeric, value by which to "shift" the response along x1. Default is 0 (no shift).
...	Additional arguments (not used).

Value

A logistic function.

Examples

x1 <- seq(-1, 1, by=0.01)
pr1 <- logisticShift(x1=x1, b1=1)
pr2 <- logisticShift(x1=x1, b1=2)
pr3 <- logisticShift(x1=x1, b1=3)
pr4 <- logisticShift(x1=x1, b0=-1, b1=3)

plot(x1, pr1, ylab='Logistic output', type='l', ylim=c(0, 1))
lines(x1, pr2, col='red')
lines(x1, pr3, col='blue')
lines(x1, pr4, col='green')

adamlilith/enmSdmPredImport documentation built on Dec. 31, 2022, 5:40 p.m.