Pluto cyclic reference

notebook.jl

### A Pluto.jl notebook ###
# v0.16.1

using Markdown
using InteractiveUtils

# ╔═╡ d00d6ce7-6cb2-4a8e-a119-aafe2d372a77
function stencil(kernel_f!, N)
	A = reshape(BandedMatrix(Zeros(N^2, N^2), (N+1, N+1)), N, N, N, N)
	_A = PaddedArray(A, 0)
	
	for I in CartesianIndices((1:N-1, 1:N-1))
		ξ, η = Tuple(I) ./ (N + 1)
		kernel_f!(view(_A, I .+ CartesianIndices((-1:1, -1:1)), I), ξ, η)
	end
	return A
end

# ╔═╡ d33ba16a-0a0b-4b8c-a0aa-12997516b14b
A = stencil(kernel_f!, 20);

# ╔═╡ 7e073004-b039-4636-947e-26b482657134
begin
	struct PaddedArray{T, N, A<:AbstractArray{T, N}} <: AbstractArray{T, N}
		parent::A
		padding::T
	end
	function PaddedArray(parent::AbstractArray{T, N}, padding=zero(T)) where {T, N}
		return PaddedArray{T, N, typeof(parent)}(parent, padding)
	end
	Base.axes(x::PaddedArray) = axes(x.parent)
	Base.size(x::PaddedArray) = size(x.parent)
	Base.getindex(x::PaddedArray, i::Int...) = get(x.parent, i, x.padding)
	Base.setindex!(x::PaddedArray, y, i::Int...) = checkbounds(Bool, x.parent, i...) && (x.parent[i...] = y)
	Base.checkbounds(::Type{Bool}, x::PaddedArray, i...) = true
end

# ╔═╡ Cell order:
# ╠═7e073004-b039-4636-947e-26b482657134
# ╠═d00d6ce7-6cb2-4a8e-a119-aafe2d372a77
# ╠═d33ba16a-0a0b-4b8c-a0aa-12997516b14b