Refactor symmetric_interval_hull of Hyperrectangle

[schillic]

LazySets.jl/src/Approximations/symmetric_interval_hull.jl

Lines 27 to 34 in 0a220f7

	function symmetric_interval_hull(S::LazySet{N}) where {N}
	# fallback returns a hyperrectangular set
	(c, r) = box_approximation_helper(S)
	if r[1] < 0
	return EmptySet{N}(dim(S))
	end
	return Hyperrectangle(zeros(N, length(c)), abs.(c) .+ r)
	end

LazySets.jl/src/Approximations/symmetric_interval_hull.jl

Lines 62 to 74 in 0a220f7

	# hyperrectangle specialization
	@inline function _maxabs(c::N, r::N) where {N}
	return c >= zero(N) ? c + r : -c + r
	end
	function symmetric_interval_hull(H::Hyperrectangle{N}) where {N}
	n = dim(H)
	r = Vector{N}(undef, n)
	@inbounds for i in 1:n
	r[i] = _maxabs(H.center[i], H.radius[i])
	end
	return Hyperrectangle(zeros(N, n), r)
	end

One of them is probably faster. Both methods should use that same code (add a new helper function with arguments c and r).

We should also try out yet another version with low and high, which may be even faster than box_approximation_helper in general.