Hi
I wand to create a random 2 vector in a loop and want it to be static.
Here is the code:

using StaticArrays
using Distributions
dist2dN = MvNormal([0., 0.],[10. 0;0 10.])
for _ in 1:5
x = @SVector [i for i in rand(dist2dN,1)]
println(x)
end

julia> @macroexpand @SVector [i for i in rand(dist2dN,1)]
quote
#= /Users/chriselrod/.julia/packages/StaticArrays/0bweZ/src/SVector.jl:66 =#
var"##292" = (i->begin
#= /Users/chriselrod/.julia/packages/StaticArrays/0bweZ/src/SVector.jl:62 =#
i
end)
#= /Users/chriselrod/.julia/packages/StaticArrays/0bweZ/src/SVector.jl:67 =#
SVector{2}((var"##292"(3.9955890431901353), var"##292"(-2.5563441673280245)))
end

Maybe the easiest way would be

using StaticArrays, LinearAlgebra
S = @SMatrix[10.0 0.0; 0.0 10.0];# I'm assuming not diagonal in general?
m = @SVector zeros(2);
L = cholesky(S).L
for _ in 1:5
x = m + L* @SVector(randn(length(m)))
println(x)
end

I get

julia> for _ in 1:5
x = m + L* @SVector(randn(length(m)))
println(x)
end
[3.747661043744402, -3.966264996727186]
[4.2503672520999265, 5.887575258272834]
[1.2384273143564963, 1.7567526130166946]
[3.092399770360624, -1.6927998659077437]
[-6.3010084683219025, -1.1313133350009374]

You can of course hard-code optimizations like not adding a zero mean if the mean is known to be 0.

Might be worth looking into a PR to Distributions.jl so that this returns an SVector:

Thanks @Elrod for the explanations. Yes indeed, when the vector is static and not mutable, it is not strange that is not changing . I’ve come up with this though,

for _ in 1:5
x = rand(dist2dN)
xss = @SVector [x[1],x[2]]
println(xss)
println(isbits(xss))
end
[-0.7533134459789248, 2.296833259646034]
true
[-3.4243299602495116, -2.7404408816986447]
true
[-1.020142875580128, -4.253875133369519]
true
[4.083471250760358, 1.2642846753752661]
true
[0.3937145507723281, -4.209228775050337]
true

It will be very good if Distributions.jl can create static objects itself.
thanks

You are right. But for my problem it is just enough (or maybe not!).
let me explain what is my problem. This 2-vector suppose to be the initial condition of a differential equation where I am using DifferentialEquations.jl to solve it. So I am just creating this SVector for each orbit and it improves benchmark (not very significantly actually).