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BergEC-jl
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Better sum

This commit is contained in:
Nuwan Yapa 2024-02-27 11:20:28 -05:00
parent 4bf2872e95
commit 5d39015976
2 changed files with 12 additions and 1 deletions
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10
helper.jl Normal file
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"Sum over array while minimizing catastrophic cancellation as much as possible"
function better_sum(arr::Array{Float64})
pos_arr = arr[arr .> 0]
neg_arr = arr[arr .< 0]
sort!(pos_arr)
sort!(neg_arr, rev=true)
return sum(pos_arr) + sum(neg_arr)
end

3
ho_basis.jl
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@ -1,12 +1,13 @@
using NuclearToolkit
using SpecialFunctions
include("helper.jl")
# Gaussian potentials in HO space
inv_factorial(n) = Iterators.prod(inv.(1:n))
sqrt_factorial(n) = Iterators.prod(sqrt.(n:-1:1))
N_lnk(l, n, k) = (-1)^(n-k) * inv_factorial(k) * binomial(n+l+1/2, n-k) * sqrt_factorial(n) / sqrt(gamma(n+l+3/2))
Talmi(l, R, k1, k2) = (1 + 1/R^2)^-(3/2 + l + k1 + k2) * gamma(3/2 + l + k1 + k2)
V_Gaussian(R, l, n1, n2) = sum([N_lnk(l, n1, k1) * N_lnk(l, n2, k2) * Talmi(l, R, k1, k2) for (k1, k2) in Iterators.product(0:n1, 0:n2)])
V_Gaussian(R, l, n1, n2) = better_sum([N_lnk(l, n1, k1) * N_lnk(l, n2, k2) * Talmi(l, R, k1, k2) for (k1, k2) in Iterators.product(0:n1, 0:n2)])
function get_sp_basis(E_max)
Es = Int[]