diff --git a/helper.jl b/helper.jl
index 4d284ba..e48b171 100644
--- a/helper.jl
+++ b/helper.jl
@@ -1,7 +1,7 @@
 using LinearAlgebra, DelimitedFiles
 
 "Sum over array while minimizing catastrophic cancellation as much as possible"
-function better_sum(arr::Array{Float64})
+function better_sum(arr::Array{T}) where T<:Real
     pos_arr = arr[arr .> 0]
     neg_arr = arr[arr .< 0]
 
diff --git a/math.jl b/math.jl
index 0556def..96c440b 100644
--- a/math.jl
+++ b/math.jl
@@ -15,7 +15,7 @@ laguerre(l, n, x) = gamma(n + l + 3/2) * better_sum([(-x * x)^k / gamma(k + l +
 ho_basis(l, n, x) = (-1)^n / sqrt_sqrt_pi * 2^((n + l + 2) / 2) * sqrt_factorial(n) / sqrt_double_factorial(2*n + 2*l + 1) * x^(l + 1) * exp(-x^2 / 2) * laguerre(l, n, x)
 
 # for implementation of simple relative coordinates
-double_factorial(n) = Iterators.prod(Float64, n:-2:1)
+double_factorial(n::Int) = Iterators.prod(big, n:-2:1)
 
 "Gaussian integral for n ∈ Integers (Ref: Wolfram MathWorld + simplifications)"
 gauss_int(a, n) = double_factorial(n - 1) / (2 * a)^((n + 1)/2) * (iseven(n) ? sqrt(π / 2) : 1)