Create a non-linear structure in higher dimensional space in Julia - julia

Question

Suppose I’m creating a non-linear structure in a 20-dim space. Right now I have code
using Random
"`Uniform(0,b)`, with `0` excluded for sure, and we really mean it."
struct PositiveUniform{T}
b::T
end
function Base.rand(rng::Random.AbstractRNG, pu::PositiveUniform)
while true
r = rand(rng)
r > 0 && return r * pu.b
end
end
m = rand(PositiveUniform(20))
mat_new = [cos(m),sin(m),cos(m),sin(m),0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]'
for i in 1:84
m = rand(PositiveUniform(20))
vector = [cos(m),sin(m),cos(m),sin(m),0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]
mat_new = vcat(mat_new, vector')
end
mat_new'
And my mat_new' is like
I'm wondering is this matrix satisfying my expectation?

Answer 1

(edit: I made a 2D structure 20 x 85, padding with zeros, since that is what was wanted, not a 20D array.)
const cols = 85
const rows = 20
const vec85 = rand(cols) .* rows
const mat2D = vcat(cos.(vec85)', sin.(vec85)', cos.(vec85)', sin.(vec85)', zeros(rows - 4, cols))
display(mat2D)
displays:
20×85 Matrix{Float64}:
-0.917208 -0.999591 -0.95458 -0.681959 0.999834 … 0.704834 0.961039 0.982991 0.967226 0.306118
0.398409 0.0286128 -0.297954 -0.731391 0.0182257 0.709372 0.276413 0.183653 -0.253917 -0.951993
-0.917208 -0.999591 -0.95458 -0.681959 0.999834 0.704834 0.961039 0.982991 0.967226 0.306118
0.398409 0.0286128 -0.297954 -0.731391 0.0182257 0.709372 0.276413 0.183653 -0.253917 -0.951993
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0 0.0 … 0.0 0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
⋮ ⋱ ⋮
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0 0.0 … 0.0 0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Note I kept your algorithm (perhaps not intended?) of setting the argument to sin and cos as nrows times rand(). If you want to pad the 2D array to contain more than just your matrix, I would look at PaddedViews.jl or similar.