mlogis: Multinomial Probabilities & Logits

In fmx: Finite Mixture Parametrization

Multinomial Probabilities & Logits

Description

Transformation between the vectors of multinomial probabilities and logits.

Usage

qmlogis(p)

pmlogis(q)

Arguments

p	double vector, multinomial probabilities
q	double vector, multinomial logits

Details

The function [pmlogis()] takes a length k-1 double vector of multinomial logits q and convert them into length k multinomial probabilities p, regarding the *first* category as reference.

The function [qmlogis()] takes a length k double vector of multinomial probabilities p and convert them into length k-1 multinomial logits q, regarding the *first* category as reference.

Value

The function [pmlogis()] returns a double vector of multinomial probabilities p.

The function [qmlogis()] returns a double vector of multinomial logits q.

Note

This transformation is a generalization of functions plogis (i.e., logit to probability) and qlogis (i.e., probability to logit).

Examples

c(2,5,3) |> qmlogis() |> pmlogis()

# various exceptions
c(1, 0) |> qmlogis() |> pmlogis()
c(0, 1) |> qmlogis() |> pmlogis()
c(0, 0, 1) |> qmlogis() |> pmlogis()
c(1, 0, 0, 0) |> qmlogis() |> pmlogis()
c(0, 1, 0, 0) |> qmlogis() |> pmlogis()
c(0, 0, 1, 0) |> qmlogis() |> pmlogis()
   

fmx documentation built on July 17, 2026, 1:07 a.m.