vmf: von Mises-Fisher distribution

In RTMBdist: Distributions Compatible with Automatic Differentiation by 'RTMB'

von Mises-Fisher distribution

Description

Density, distribution function, and random generation for the von Mises-Fisher distribution.

Usage

dvmf(x, mu, kappa, log = FALSE)

rvmf(n, mu, kappa)

Arguments

x	unit vector or matrix (with each row being a unit vector) of evaluation points
mu	unit mean vector
kappa	non-negative numeric value for the concentration parameter of the distribution.
log	logical; if TRUE, densities are returned on the log scale.
n	number of random values to return.

Details

This implementation of dvmf allows for automatic differentiation with RTMB. rvmf is a reparameterised import from movMF::rmovMF.

Value

dvmf gives the density and rvm generates random deviates.

Examples

set.seed(123)
# single parameter set
mu <- rep(1, 3) / sqrt(3)
kappa <- 4
x <- rvmf(1, mu, kappa)
d <- dvmf(x, mu, kappa)

# vectorised over parameters
mu <- matrix(mu, nrow = 1)
mu <- mu[rep(1,10), ]
kappa <- rep(kappa, 10)
x <- rvmf(10, mu, kappa)
d <- dvmf(x, mu, kappa)

RTMBdist documentation built on April 1, 2026, 5:07 p.m.