Incomplete Cholesky Factorization in Julia

using LinearAlgebra
function ichol(M)
	!isposdef(M) ? error("Matrix must be positive semi-definite") : nothing
	A = deepcopy(M)
	n = size(A, 1)
	for k in 1:n
		A[k,k] = sqrt(A[k,k])
		for i in (k + 1):n
	        A[i,k] = A[i,k] / A[k,k]
		end
		for j in (k + 1):n, i in j:n
	        if A[i,j] != 0
	            A[i,j] = A[i,j] - A[i,k] * A[j,k]
	        end
		end
	end
    for i in 1:n, j in i+1:n
        A[i,j] = 0
    end
	return A
end