curv_vmf_polysph {polykde} | R Documentation |
Curvature of a polyspherical von Mises–Fisher density
Description
Computes the curvature matrix
\boldsymbol{R}(\boldsymbol{\kappa})
of a product of von Mises–Fisher
densities on the polysphere. This curvature is used in the rule-of-thumb
selector bw_rot_polysph
.
Usage
curv_vmf_polysph(kappa, d, log = FALSE)
Arguments
kappa |
a vector of size |
d |
vector of size |
log |
compute the (entrywise) logarithm of the curvature matrix?
Defaults to |
Value
A matrix of size c(length(r), length(r))
.
Examples
# Curvature matrix
d <- 2:4
kappa <- 1:3
curv_vmf_polysph(kappa = kappa, d = d)
curv_vmf_polysph(kappa = kappa, d = d, log = TRUE)
# Equivalence on the sphere with DirStats::R_Psi_mixvmf
drop(curv_vmf_polysph(kappa = kappa[1], d = d[1]))
d[1]^2 * DirStats::R_Psi_mixvmf(q = d[1], mu = rbind(c(rep(0, d[1]), 1)),
kappa = kappa[1], p = 1)
[Package polykde version 1.1.4 Index]