1 Introduction

Some post-processing and visualisation tools cannot handle mesh refinement or multi-block systems. These tools then require interpolating the result onto a regular, uniform grid. This is what this thorn does.

InterpToArray can interpolate to 0D, 1D, 2D, and 3D grids. The interpolation result is stored in grid arrays. These can be either replicated or distributed over all processes. Note that using replicated (DISTRIB=constant) grid arrays can require a substantial amount of memory on each process.

2 Numerical Implementation

InterpToArray uses standard Cactus interpolators such as PUGHInterp or CarpetInterp.

3 Using This Thorn

The variables which should be interpolated are specified by parameters; currently, up to 100 variables can be interpolated.

The interpolator and its options are also specified via parameters.

Finally, the locations of the points of the regular grid are also specified via parameters. These grid points are specified via an origin and offsets, and they do not have to be aligned with the coordinate axes. For example, a 2D grid is specified via three (real) vectors \(x^a\), \(di^a\), and \(dj^a\), and via its (integer) size \(ni\) and \(nj\). The coordinates of the grid points are then given via

for \(0 \le i < ni\) and \(0 \le j < nj\). Grids with other dimensions are specified equivalently.

4 Parameters

array1d_vars	Scope: restricted	STRING
Description: Names of the grid functions that should be interpolated on a line
Range		Default: (none)
	do not interpolate
see [1] below	grid function name

[1]

\^[A-Za-z][A-Za-z0-9\_]*[:][:][A-Za-z][A-Za-z0-9\_]*\$

array2d_vars	Scope: restricted	STRING
Description: Names of the grid functions that should be interpolated on a 2D grid
Range		Default: (none)
	do not interpolate
see [1] below	grid function name

[1]

\^[A-Za-z][A-Za-z0-9\_]*[:][:][A-Za-z][A-Za-z0-9\_]*\$

array3d_vars	Scope: restricted	STRING
Description: Names of the grid functions that should be interpolated on a 3D grid
Range		Default: (none)
	do not interpolate
see [1] below	grid function name

[1]

\^[A-Za-z][A-Za-z0-9\_]*[:][:][A-Za-z][A-Za-z0-9\_]*\$

parray1d_vars	Scope: restricted	STRING
Description: Names of the grid functions that should be interpolated on a line
Range		Default: (none)
	do not interpolate
see [1] below	grid function name

[1]

\^[A-Za-z][A-Za-z0-9\_]*[:][:][A-Za-z][A-Za-z0-9\_]*\$

parray2d_vars	Scope: restricted	STRING
Description: Names of the grid functions that should be interpolated on a 2D grid
Range		Default: (none)
	do not interpolate
see [1] below	grid function name

[1]

\^[A-Za-z][A-Za-z0-9\_]*[:][:][A-Za-z][A-Za-z0-9\_]*\$

parray3d_vars	Scope: restricted	STRING
Description: Names of the grid functions that should be interpolated on a 3D grid
Range		Default: (none)
	do not interpolate
see [1] below	grid function name

[1]

\^[A-Za-z][A-Za-z0-9\_]*[:][:][A-Za-z][A-Za-z0-9\_]*\$

scalar_vars	Scope: restricted	STRING
Description: Names of the grid functions that should be interpolated on a point
Range		Default: (none)
	do not interpolate
see [1] below	grid function name

[1]

\^[A-Za-z][A-Za-z0-9\_]*[:][:][A-Za-z][A-Za-z0-9\_]*\$

5 Interfaces

General

Implements:

interptoarray

Grid Variables

5.0.1 PUBLIC GROUPS

6 Schedule

This section lists all the variables which are assigned storage by thorn CactusNumerical/InterpToArray. 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_ANALYSIS

  interptoarray

  interpolate to grid arrays