param-utils: Internal functions to map between Euclidean and spherical...

In graphpcor: Models for Correlation Matrices Based on Graphs

Internal functions to map between Euclidean and spherical coordinates

Description

Internal functions to map between Euclidean and spherical coordinates

Usage

rphi2x(rphi)

x2rphi(x)

rtheta(n, lambda = 1, R, theta.base)

dtheta(theta, lambda, theta.base, H.elements)

Arguments

rphi	numeric vector where the first element is the radius and the remaining are the angles
x	parameters in the Euclidean space to be converted
n	integer to define the size of the correlation matrix
lambda	numeric as the parameter for the Exponential distribution of the radius
R	scaling matrix (square root of the Hessian around the base model)
theta.base	numeric vector of the base model
theta	numeric vector of length m.
H.elements	list output of theta2H

Details

For details, please see the wikipedia entry on 'N-sphere' at N-sphere

Functions

• rphi2x(): Map between spherical to Euclidean coordinates

• x2rphi(): Transform from Euclidean coordinates to spherical

• rtheta(): Drawn samples from the PC-prior for correlation

• dtheta(): PC-prior density for the correlation matrix

graphpcor documentation built on March 23, 2026, 9:07 a.m.