Creating Constraint Violating Initial Data

Gabrielle Allen

\(Date\)

Abstract

The IDConstraintViolate thorn creates initial data which purposefully violates the constraint equations for testing purposes.

1 Gaussian

Choosing the ADMBase parameter initial_data to have the value Constraint violating gaussian creates initial data with the form

\begin {eqnarray*} g_{xx} = g_{yy} = g_{zz} &=& 1 + A \exp \left (\frac {-(r-r_0)^2}{\sigma ^2}\right ) \\ g_{xy} = g_{xz} = g_{yz} &=& 0 \\ K_{ij} &=& 0 \end {eqnarray*}

where the size and shape of the Gaussian is specified by parameters, \(A\)=amplitude, \(r_0\)=radius and \(\sigma \)=sigma.

2 Parameters


amplitude	Scope: private	REAL

Description: The amplitude of the waves

Range		Default: 0.001
:	No restriction


radius	Scope: private	REAL

Description: The radial position of the Gaussian wave

Range		Default: 0.0
0:*	Positive


sigma	Scope: private	REAL

Description: The sigma for the Gaussian wave

Range		Default: 0.1
(0:*	Positive


initial_data	Scope: shared from ADMBASE	KEYWORD

Extends ranges:

see [1] below	Constraint violating Gaussian

[1]

constraint violating gaussian


metric_type	Scope: shared from ADMBASE	KEYWORD

3 Interfaces

General

Implements:

idconstraintviolate

Inherits:

admbase

grid

4 Schedule

This section lists all the variables which are assigned storage by thorn EinsteinInitialData/IDConstraintViolate. Storage can either last for the duration of the run (Always means that if this thorn is activated storage will be assigned, Conditional means that if this thorn is activated storage will be assigned for the duration of the run if some condition is met), or can be turned on for the duration of a schedule function.

Storage

NONE

Scheduled Functions

CCTK_PARAMCHECK

idconstraintviolate_paramchecker

check parameters

	Language:	c
	Type:	function

ADMBase_InitialData

idconstraintviolate_initial

set up constraint violating initial data

	Language:	fortran
	Type:	function