# sample_sphere_surface: Sample vectors uniformly from the surface of a sphere

## Description

Sample finite-dimensional vectors to use as latent position vectors in
random dot product graphs

## Usage

sample_sphere_surface(dim, n = 1, radius = 1, positive = TRUE)

## Arguments

dim

Integer scalar, the dimension of the random vectors.

n

Integer scalar, the sample size.

radius

Numeric scalar, the radius of the sphere to sample.

positive

Logical scalar, whether to sample from the positive orthant
of the sphere.

## Value

A `dim`

(length of the `alpha`

vector for
`sample_dirichlet`

) times `n`

matrix, whose columns are the sample
vectors.

## Details

`sample_sphere_surface`

generates uniform samples from \(S^{dim-1}\)
(the `(dim-1)`

-sphere) with radius `radius`

, i.e. the Euclidean
norm of the samples equal `radius`

.

## Examples

# NOT RUN {
lpvs.sph <- sample_sphere_surface(dim=10, n=20, radius=1)
RDP.graph.3 <- sample_dot_product(lpvs.sph)
vec.norm <- apply(lpvs.sph, 2, function(x) { sum(x^2) })
vec.norm
# }