diff --git a/calculations/ACCC.jl b/calculations/ACCC.jl index 2952da9..4f506bf 100644 --- a/calculations/ACCC.jl +++ b/calculations/ACCC.jl @@ -20,7 +20,7 @@ c0 = find_zero(quick_extrapolate, 0.85) # Calculation of training and extrapolating E training_c = range(1.2, 0.9, 9) # original: range(1.35, 0.9, 5) training_E = [quick_pole_E(V_system(c)) for c in training_c] -training_k = new_sqrt.(2μ .* training_E) +training_k = alt_sqrt.(2μ .* training_E) extrapolating_c = range(0.78, 0.45, 7) # original: range(0.75, 0.40, 8) exact_E = [quick_pole_E(V_system(c)) for c in extrapolating_c] @@ -28,7 +28,7 @@ exact_E = [quick_pole_E(V_system(c)) for c in extrapolating_c] order::Int = ceil((length(training_c) - 1) / 2) # order of the Pade approximant # Solve coefficients as a linear system -M_left_element(c, i) = complex(c - c0)^(i/2) +M_left_element(c, i) = alt_sqrt(c - c0)^i M_left = M_left_element.(training_c, (0:order)') M_right = -training_k .* M_left[:, 2:end] # remove the first column M = hcat(M_left, M_right) # M = [M_left | M_right] @@ -37,14 +37,11 @@ a = sol[1:order+1] b = [1; sol[order+2:end]] # Pade approximant -polynomial(a, c) = sum(i -> a[i+1] * complex(c - c0)^(i/2), 0:order) +polynomial(a, c) = sum(i -> a[i+1] * alt_sqrt(c - c0)^i, 0:order) pade_approx(c) = polynomial(a, c) / polynomial(b, c) # Extrapolate extrapolated_k = pade_approx.([training_c; extrapolating_c]) -if real.(extrapolated_k[end]) < 0 # flip if following anti-resonance - extrapolated_k = -conj.(extrapolated_k) -end extrapolated_E = (extrapolated_k .^ 2) / (2μ) # Plotting diff --git a/common.jl b/common.jl index c5e537d..97d82c3 100644 --- a/common.jl +++ b/common.jl @@ -2,8 +2,8 @@ using LinearAlgebra, DelimitedFiles, SparseArrays @enum coordinate_system jacobi src -"Square root function with the branch cut along the postive real axis" -new_sqrt(x::Number)::ComplexF64 = im * sqrt(complex(-x)) +"Square root function with the branch cut along the postive imaginary axis" +alt_sqrt(x::Number)::ComplexF64 = sqrt(im * x) / sqrt(im) "Sum over array while minimizing catastrophic cancellation as much as possible" function better_sum(arr::Array{T}) where T<:Real