RTMBdist (version 0.1.0)

vmf: 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)

Value

dvmf gives the density and rvm generates random deviates.

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.

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)