Incorrect integration results depending on integration bounds, using quadgk directly works about integrals.jl HOT 1 CLOSED

using Integrals
using QuadGK
using Plots

function integrand(E::Real, eta::Real)
    return exp(-E^2/2) / (sqrt(2π) * (exp(E-eta) + 1))
end

function using_quadgk(eta::Real, lim::Real)
    iq(x) = integrand(x, eta)
    res, err = quadgk(iq, -lim, lim)
    return res
end

function using_integrals(eta::Real, lim::Real)
    ip = IntegralProblem(integrand, -lim, lim, eta)
    return solve(ip, QuadGKJL();abstol=0.0)[1]
end

er = LinRange(-30, 2, 200)
lim = 100
plot(er, using_quadgk.(er, lim), yscale=:log10, label="QuadGK");
plot!(er, using_integrals.(er, lim), yscale=:log10, label="Integrals")