# Malfliet–Tjon V (MT-V) — the standard few-body benchmark
# Reference 2-body bound state: E₂ ≈ −0.41 MeV

include("../Hamiltonian.jl")
mode = cpu_tensor
T = Float32 # single-precision mode

V_R = 1458.05 # MeV·fm   
μ_R = 3.11 # fm⁻¹
V_A = -578.09 # MeV·fm 
μ_A = 1.55 # fm⁻¹

r2_reg = 0.000001 # fm², regularization parameter to avoid singularity at r=0
V_MTV(r2) = V_R * exp(−μ_R * sqrt(r2))/sqrt(r2 + r2_reg)  +  V_A * exp(−μ_A * sqrt(r2))/sqrt(r2 + r2_reg)

# ℏ²/m_N = 41.47 MeV·fm²   (m_N c² = 938.92 MeV)
μ = (1 / 41.47) / 2

ϕ = 0
d = 3
n = 2
N = 80
L = 20
n_imag = 1

s = system{T}(d, n, N, L, μ)
H = Hamiltonian{T}(s, V_MTV, ϕ, n_imag, mode)
@time evals, _, info = eig(H, 10, resonances = false)

sort!(evals)
display(evals[1:3])

# Result incorrect and does not converge, most probably due to singularity at r=0