.. Planetary Initial Conditions Jacob Kegerreis, 14th July 2022 .. _planetary_initial_conditions: Initial Conditions ================== Tools for the creation of initial conditions are available via the `WoMa `_ and `SEAGen `_ open-source python packages, including: creating spherical or spinning planetary (or similar) profiles; placing particles to match arbitrary profiles with precise SPH densities; and setting the initial target and impactor positions and velocities, as presented in `Kegerreis et al. (2019) `_ and `Ruiz-Bonilla et al. (2020) `_ . They are available with documentation and examples at https://github.com/srbonilla/WoMa and https://github.com/jkeger/seagen, or can be installed directly with ``pip`` (https://pypi.org/project/woma/, https://pypi.org/project/seagen/). Settling initial conditions with fixed entropies ------------------------------------------------ If the particles' equations of state include specific entropies, and the initial conditions file includes specific entropies for each particle (in ``PartType0/Entropies``), then configuring SWIFT with ``--enable-planetary-fixed-entropy`` will override the internal energy of each particle each step such that its specific entropy remains constant. This should be used with caution, but may be a convenient way to maintain an entropy profile while initial conditions settle to equilibrium with their slightly different SPH densities.