perform_apm Module Procedure

Initial particle number

Initial particle positions

Initial particle volume

Array to store the smoothing lengths computed at the end of the APM iteration

Array to store the baryon number per particle computed at the end of the APM iteration

Center of the matter object, from the \(\mathrm{ID}\)

Center of mass of the matter object, from the \(\mathrm{ID}\)

Mass of the matter object

Sizes of the matter object

\(\mathrm{EOS}\) to use when computing the pressure

Maximum number of APM iterations, irrespective of the EXIT condition

Sets the EXIT condition: If the average over all the particles of the relative error in the density estimate grows max_inc times, exit the iteration.

If .TRUE. performs a second iteration after the APM one, without moving the particles, changing their mass in order to better match the star density. The mass ratio grows very fast in all the tried experiments, hence the suggested value is .FALSE.

If .TRUE., the baryon number per particle nu is corrected to include the total baryonic masses of the stars.

Maximum mass ratio (equivalently baryon number ratio) to be used in the one-time-only final correction of the particle masses to match the star density even better (without moving the particles)

Sets the EXIT condition: If the baryon number ratio is within 2.5% of nuratio_des, exit the iteration Set nuratio_des to 0 to deactivate and exit the APM iteration using max_inc

If .TRUE., uses the physical pressure computed with the \(\mathrm{EOS}\) using the SPH estimate of the density nlrf_sph, to compute the artificial pressure. Otherwise, the density variable nstar_sph is used to compute the artificial pressure

If .TRUE., the ghost particles will be placed and have a baryon number such to reproduce the density of the outermost layers (r > 99% of the minimum radius) of the object. If .TRUE., the arguments nx_gh, ny_gh, nz_gh, ghost_dist are ignored; if .FALSE., they are instead used to place the ghost particles

If .TRUE., the ghost particles will slowly move away from the surface of the star during the iteration (depending on the EXIT condition chosen, this happens in slightly different ways), to allow for the real particles to get closer to the surface

Number of lattice points in the x direction for ghosts

Number of lattice points in the y direction for ghosts

Number of lattice points in the z direction for ghosts

Distance between the ghost particles and the surface of the matter object considered (star, ejecta, etc...)

If .TRUE., allows particles to move where the density is 0, and displace them using only the smoothing term. This can be useful when the system has an irregular geometry, as, for example, an ejecta; .FALSE. otherwise

If .TRUE., removes the particles placed where the density is 0, at the end of the APM iteration; .FALSE. otherwise

Prints the particle positions to a formatted file every print_step steps

Name for the formatted file where the initial particle positions and the ghost positions will be printed

Name for the formatted file where the particle positions and the ghost positions will be printed every 15 iterations

Name for the formatted file where various quantities related to the particle distribution, the baryon number particle and the kernel estimate of the density will be printed at the end of the APM iteration

Returns 1 if the position is not valid, 0 otherwise

Surface of the matter object