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apparent_horizon

This page contains a full reference of all parameters available for the apparent_horizon module. At the bottom of the page you can find an example parameter block that can be used in your parameter file.

apparent_horizon

Apparent horizon finder. Solves for h(theta,phi) as the trapped surface radius using a spectral expansion in real spherical harmonics and Newton-Raphson iteration on the expansion scalar Theta.

Name:	n_horizons
Type:	int
Default:	0
Range:	[0,*)
Description:	Number of apparent horizons to search for.

Name:	find_every
Type:	int
Default:	-1
Range:	[-1,*)
Description:	How often to search for apparent horizons (in iterations). Set to -1 to disable.

Name:	verbose
Type:	bool
Default:	False
Description:	Print per-iteration convergence information.

Name:	compute_fluxes
Type:	bool
Default:	False
Description:	When true, compute GRMHD surface fluxes (Mdot, Edot, Ldot, Phi) on each found apparent horizon. Requires GRMHD auxiliary variables.

horizons

Name:	name
Type:	string
Default:	AH0
Description:	Unique name for this horizon. Used in output filenames.

Name:	l_max
Type:	int
Default:	8
Range:	[1,20]
Description:	Maximum spherical harmonic degree. Collocation grid has (l_max+1) x (2*l_max+1) points.

Name:	initial_radius
Type:	double
Default:	0.5
Range:	(0,*)
Description:	Initial guess radius for the horizon (coordinate units).

Name:	center_x
Type:	double
Default:	0.0
Range:	(*,*)
Description:	Initial x coordinate of the horizon center.

Name:	center_y
Type:	double
Default:	0.0
Range:	(*,*)
Description:	Initial y coordinate of the horizon center.

Name:	center_z
Type:	double
Default:	0.0
Range:	(*,*)
Description:	Initial z coordinate of the horizon center.

Name:	tolerance
Type:	double
Default:	1e-10
Range:	(0,*)
Description:	Convergence tolerance on the L2 norm of the expansion residual.

Name:	max_iterations
Type:	int
Default:	50
Range:	[1,*)
Description:	Maximum number of Newton-Raphson iterations per find attempt.

Name:	jacobian_eps
Type:	double
Default:	1e-06
Range:	(0,*)
Description:	Perturbation size for finite-difference Jacobian computation.

Name:	track_center
Type:	bool
Default:	True
Description:	If true, update the horizon center to the centroid of the previously found horizon. Provides tracking.