API

CartesianIC{T<:AbstractFloat} <: InitialConditions{T}

Initial conditions, specified by the Cartesian coordinates and masses of each body.

Fields

• x::Matrix{T} : Positions of each body [dimension, body].
• v::Matrix{T} : Velocities of each body [dimension, body].
• m::Vector{T} : masses of each body.
• nbody::Int64 : Number of bodies in system.
• t0::T : Initial time.

Elements{T<:AbstractFloat} <: AbstractInitialConditions

Orbital elements of a binary, and mass of a 'outer' body. See Tutorials for units and conventions.

Fields

• m::T : Mass of outer body.
• P::T : Period [Days].
• t0::T : Initial time of transit [Days].
• ecosω::T : Eccentricity vector x-component (eccentricity times cosine of the argument of periastron)
• esinω::T : Eccentricity vector y-component (eccentricity times sine of the argument of periastron)
• I::T : Inclination, as measured from sky-plane [Radians].
• Ω::T : Longitude of ascending node, as measured from +x-axis [Radians].
• a::T : Orbital semi-major axis [AU].
• e::T : Eccentricity.
• ω::T : Argument of periastron [Radians].
• tp::T : Time of periastron passage [Days].

Elements(m,P,t0,ecosω,esinω,I,Ω)

Main Elements constructor. May use keyword arguments, see Tutorials.

ElementsIC{T<:AbstractFloat} <: InitialConditions{T}

Initial conditions, specified by a hierarchy vector and orbital elements.

Fields

• elements::Matrix{T} : Masses and orbital elements.
• ϵ::Matrix{T} : Matrix of Jacobi coordinates
• amat::Matrix{T} : 'A' matrix from Hamers and Portegies Zwart 2016.
• nbody::Int64 : Number of bodies.
• m::Vector{T} : Masses of bodies.
• t0::T : Initial time [Days].

ElementsIC(t0,H,elems)

Collects Elements and produces an ElementsIC struct.

Arguments

• t0::T : Initial time [Days].
• H : Hierarchy specification.
• elems : The orbital elements and masses of the system.

There are a number of way to specify the initial conditions. Below we've described the arguments ElementsIC takes. Any combination of H and elems may be used. For a concrete example see Tutorials.

Elements

• elems... : A sequence of Elements{T}. Elements should be passed in the order they appear in the hierarchy (left to right).
• elems::Vector{Elements} : A vector of Elements. As above, Elements should be in order.
• elems::Matrix{T} : An matrix containing the masses and orbital elements.
• elems::String : Name of a file containing the masses and orbital elements.

Each method is simply populating the ElementsIC.elements field, which is a Matrix{T}.

Hierarchy

• Number of bodies: H::Int64: The system will be given by a 'fully-nested' Keplerian.

H = 4 corresponds to:

3        ____|____
        |         |
2    ___|___      d
    |       |
1 __|__     c
 |     |
 a     b

• Hierarchy Vector: H::Vector{Int64}: The first elements is the number of bodies. Each subsequent is the number of binaries on a level of the hierarchy.

H = [4,2,1]. Two binaries on level 1, one on level 2.

2    ____|____
    |         |
1 __|__     __|__
 |     |   |     |
 a     b   c     d

• Full Hierarchy Matrix: H::Matrix{<:Real}: Provide the hierarchy matrix, directly.

H = [-1 1 0 0; 0 0 -1 1; -1 -1 1 1; -1 -1 -1 -1]. Produces the same system as H = [4,2,1].

State{T<:AbstractFloat} <: AbstractState

Current state of simulation.

Fields (relevant to the user)

• x::Matrix{T} : Positions of each body [dimension, body].
• v::Matrix{T} : Velocities of each body [dimension, body].
• t::Vector{T} : Current time of simulation.
• m::Vector{T} : Masses of each body.
• jac_step::Matrix{T} : Current Jacobian.
• dqdt::Vector{T} : Derivative with respect to time.

State(ic)

Constructor for State type.

Arguments

• ic::InitialConditions{T} : Initial conditions for the system.

Integrator{T<:AbstractFloat}

Integrator. Used as a functor to integrate a State.

Fields

• scheme::Function : The integration scheme to use.
• h::T : Step size.
• t0::T : Initial time.
• tmax::T : Duration of simulation.

TransitParameters{T<:AbstractFloat} <: TransitOutput{T}

Transit times, impact parameters, sky-velocities, and derivatives.

(User-facing) Fields

• ttbv::Matrix{T} : The transit times, impact parameter, and sky-velocity of each body.
• dtbvdq0::Array{T,5} : Derivatives of the transit times, impact parameters, and sky-velocities with respect to the initial Cartesian coordinates and masses.
• dtbvdelements::Array{T,5} : Derivatives of the transit times, impact parameters, and sky-velocities with respect to the initial orbital elements and masses.

TransitParameters(tmax, ic; ti)

Constructor for TransitParameters type.

Arguments

• tmax::T : Expected total elapsed integration time. (Allocates arrays accordingly)
• ic::ElementsIC{T} : Initial conditions for the system

Optional

• ti::Int64=1 : Index of the body with respect to which transits are measured. (Default is the central body)

TransitTiming{T<:AbstractFloat} <: TransitOutput{T}

Transit times and derivatives.

(User-facing) Fields

• tt::Matrix{T} : The transit times of each body.
• dtdq0::Array{T,4} : Derivatives of the transit times with respect to the initial Cartesian coordinates and masses.
• dtdelements::Array{T,4} : Derivatives of the transit times with respect to the initial orbital elements and masses.

TransitTiming(tmax, ic; ti)

Constructor for TransitTiming type.

Arguments

• tmax::T : Expected total elapsed integration time. (Allocates arrays accordingly)
• ic::ElementsIC{T} : Initial conditions for the system

Optional

• ti::Int64=1 : Index of the body with respect to which transits are measured. (Default is the central body)