## Creating Constraint Violating Initial Data

$Date$

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

$\begin{array}{rcll}{g}_{xx}={g}_{yy}={g}_{zz}& =& 1+Aexp\left(\frac{-{\left(r-{r}_{0}\right)}^{2}}{{\sigma }^{2}}\right)& \text{}\\ {g}_{xy}={g}_{xz}={g}_{yz}& =& 0& \text{}\\ {K}_{ij}& =& 0& \text{}\end{array}$

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:

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.

NONE

#### Scheduled Functions

CCTK_PARAMCHECK

idconstraintviolate_paramchecker

check parameters

 Language: c Type: function