# Planetary Hydro Scheme¶

This scheme is based on Minimal (Density-Energy) SPH but also allows multiple materials, meaning that different SPH particles can be assigned different equations of state (EoS). Every SPH particle then requires and carries the additional MaterialID flag from the initial conditions file. This flag indicates the particle’s material and which EoS it should use.

The Balsara viscosity switch is used by default, but can be disabled by compiling SWIFT with make CFLAGS=-DPLANETARY_SPH_NO_BALSARA.