init_SISLens(x_c::RV=0.0, y_c::RV=0.0, v_d::RV=NaN)

Initialize a Singular Isothermal Sphere (SIS) lens with the given parameters.

potential!(ψ::T, θx::T, θy::T, θxc::RV, θyc::RV, vd::RV) where T <: RV

potential!(ψ::T, θx::T, θy::T, θxc::RV, θyc::RV, vd::RV) where T <: ROA

deflection!(ψx::T, ψy::T, θx::T, θy::T, θxc::RV, θyc::RV, vd::RV) where T <: RV

deflection!(ψx::T, ψy::T, θx::T, θy::T, θxc::RV, θyc::RV, vd::RV) where T <: ROA

jacobian!(ψxx::T, ψyy::T, ψxy::T, θx::T, θy::T, θxc::RV, θyc::RV, vd::RV) where T <: RV

jacobian!(ψxx::T, ψyy::T, ψxy::T, θx::T, θy::T, θxc::RV, θyc::RV, vd::RV) where T <: ROA

einstein_angle(;D_ds::Float64=NaN, D_s::Float64=NaN, v_d::RV=NaN)