🌌 `GalacticPotentials.jl`

An extension of ModelingToolkit.jl which provides common galactic potentials.

Installation

Choose one of the two lines below!

Pkg.add("GalacticPotentials.jl")    # in Julia code

pkg> GalacticPotentials             # in Julia's REPL

Usage

Potentials are defined as subtypes of ModelingToolkit.jl models. They can be converted to ODESystem and ODEProblem types to interact with the rest of the SciML ecosystem.

using Plots
using ModelingToolkit
using DifferentialEquations
using GalacticPotentials

let model = ODESystem(PlummerPotential())

    p = @nonamespace Dict(
        model.G => 6.6743e-20, # field strength (km³ kg⁻¹ s⁻²)
        model.m => 6e31,       # mass (kg)
        model.b => 1e-6        # softening parameter (unitless)
    )

    u0 = @nonamespace Dict(
        model.x => 11e5,
        model.y => 5e5,
        model.z => 0,
        model.Δx => 1e3,
        model.Δy => 1e3,
        model.Δz => 0
    )

    ts = (0.0, 1e6)

    problem = ODEProblem(model, u0, ts, p)
    solution = solve(problem; reltol=1e-14, abstol=1e-14)

    plot(solution; idxs=(:x,:y), label=:none, dpi = 400, aspect_ratio=:equal)
end

Credits

This package is bootstrapped off of gala and galpy, two rich Python packages for galactic dynamics. I aim to learn about galactic dynamics by integrating the models within these two popular Python packages into the SciML ecosystem. The Gala license is pasted below.

Gala License

The MIT License (MIT)

Copyright (c) 2012-2024 Adrian M. Price-Whelan

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

The scalar field symbolic-numerics are copied and modified versions of AbstractSystem interfaces within ModelingToolkit.jl. The field implementations in this package are highly unstable; they may change in the near future. The ModelingToolkit.jl license is pasted below.

`ModelingToolkit.jl` License

The ModelingToolkit.jl package is licensed under the MIT "Expat" License:

> Copyright (c) 2018-22: Yingbo Ma, Christopher Rackauckas, Julia Computing, and
> contributors
> 
> Permission is hereby granted, free of charge, to any person obtaining a copy
> 
> of this software and associated documentation files (the "Software"), to deal
> 
> in the Software without restriction, including without limitation the rights
> 
> to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
> 
> copies of the Software, and to permit persons to whom the Software is
> 
> furnished to do so, subject to the following conditions:
> 
> The above copyright notice and this permission notice shall be included in all
> 
> copies or substantial portions of the Software.
> 
> THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> 
> IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> 
> FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
> 
> AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> 
> LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
> 
> OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
> 
> SOFTWARE.

The code in `src/structural_transformation/bipartite_tearing/modia_tearing.jl`,
which is from the [Modia.jl](https://github.com/ModiaSim/Modia.jl) project, is
licensed as follows:

MIT License

Copyright (c) 2017-2018 ModiaSim developers

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.