Planned Features

[nstarman]

This meta-issue tracks a host of planned features. Features that are being discussed, but might not be realized should be added and discussed in Discussions or on a Project board.

Potentials

Of / On a Potential Class:

• Dynamical Friction prescriptions (e.g. Chandrasekhar). This will probably be implemented as a wrapper that takes a potential and a dynamical friction prescription object (see Add dynamical friction wrapper #309). Care should be taken to make sure this is compatible with planned stress-energy tensor formalisms.
• Densities as Potentials (Support Density -> Potential via vmapped mesh solution #132).
• Symmetry-aware transformations for inputs to potentials (Support symmetries in potentials #189)
• Systematize all the parameter names (Parameter names #64)
• Triaxiality in the potential (✨ feat(potential): transformed and triaxial potentials #658)
• Triaxiality in the density
• Moving potentials via transformation framework
• Long-Murali type potentials (Rename LongMuraliBarPotential to ... #305)
• Stress-Energy Tensors
• TwoPowerLawPotential : $\rho \propto \frac{1}{(r/r_s)^\alpha (1+r/r_s)^{\beta-\alpha}}$
• Dehnen 1993 typed potentials: cored (alpha=0) and not.
• HomogeneousSphere
• Interpolated potentials. Starting with the spherical case.
• King potential for a king profile
• Einasto potential
• Shuster's potentials, of which n=5 is Plummer
• Lynden-Bell 1962 toroidal
• Toomre (1963), Kuzmin (1956) disks

Functions:

• derivatives of circular_velocity
• epicyclic_frequency
• 'flattening'
• radius_lindblad_resonance
• circular_angular_speed (see circular_velocity)
• torque terms
• half_mass_radius
• dynamical_time
• escape_velocity
• frequencies, e.g. vertical

Action-Angles (transferring #191)

• AA transformations via Burkhart normalization
• O2GF (should be "easy", and @jnibauer is going to have a go at it!)
• Staeckel Fudge (@adrn started this but got stuck on some math. Maybe we can convince @jls713 to come help :))
• Spherical action solver
• 1D action solver

Dynamics

• Simulation class (Add a Simulation class to support N-body integration and particle collections #193)

Orbits:

• IAS15 symplectic solver: (See also Implement the IAS15 solver patrick-kidger/diffrax#437)
• Add option to integrate phase-space volumes (not individual orbits)
• Monte Carlo uncertainties approximation in orbits.
  • Separate MonteCarloMeasurement quax library
  • Support MonteCarloMeasurement in Quantity
  • Support Quantity(MonteCarloMeasurement) in Orbit
• Analytic uncertainty approximation in orbits.
  • Separate Uncertainty quax library with Quantity support
  • Get diffrax to support quax and then Uncertainty. (see Support for uncertainty propagation? patrick-kidger/diffrax#438)
  • Support in Orbit and above
• Analytic orbits using Lynden-Bell 2015

Streams:

• Stream re-weighting for mass-loss history Add example of how to re-weight a mock stream to paint on a mass-loss history #215
• Core spray as an additional DF (Add core spraying to stream sim #287)
• Add option to integrate the phase-space volume of a stream, where the phase-space density is removed from the progenitor
• Orbital poles: from the stream track, from the angular momentum. Individual and average (+ variance)
• Interpolated stream track
• Dense stream solution (See Interpolated MockStream #251)
• Footprint class for observations.
• Pre-calculating the position derivative from Streamline to Particle Spray so that you can calculate the "correction" once and then only need to run streakline to get a stream.

Functions:

• Effective potential
• jacobi_radius. All the different approximations. And a separate implementation of each. UPDATE: see galax.dynamics.cluster.tidal_radius
• Jacobi / Roche surface
• calculation of the Lagrange points, in particular L1, L2. UPDATE: see galax.dynamics.cluster.lagrange_points