Allowed Options

Cactus understands the following options. These options are interpreted by the driver, not by Cactus. The current set of options is useful for Berger-Oliger mesh refinement which has subcycling in time, and for multi-patch simulations in which the domain is split into several distinct patches. Given this, the meanings of the options below is only tentative, and their exact meaning needs to be obtained from the driver documentation. The standard driver PUGH ignores all options.

Option names are case-insensitive. There can be several options given at the same time.

META

This routine will only be called once, even if several simulations are performed at the same time. This can be used, for example, to initialise external libraries, or to set up data structures that live in global variables.

GLOBAL

This routine will only be called once on a grid hierarchy, not for all subgrids making up the hierarchy. This can be used, for example, for analysis routines which use global reduction or interpolation routines rather than the local subgrid passed to them, and hence should only be called once.

LEVEL

This routine will only be called once on any ``level'' of the grid hierarchy. That is, it will only be called once for any set of sub-grids which have the same cctk_levfac numbers.

SINGLEMAP

This routine will only be called once on any of the ``patches'' that form a ``level'' of the grid hierarchy.

LOCAL (this is the default)

This routine will be called on every ``component''.

When the above options are used, it is often the case that a certain routine should e.g. be called at the time for a GLOBAL routine, but should actually loop over all ``components''. The following set of options allows this:

LOOP-META

Loop once.

LOOP-GLOBAL

Loop over all simulations.

LOOP-LEVEL

Loop over all ``levels''.

LOOP-SINGLEMAP

Loop over all ``patches''.

LOOP-LOCAL

Loop over all ``components''.

For example, the specification

  OPTIONS: global loop-local

schedules a routine at those time when a GLOBAL routine is scheduled, and then calls the routine in a loop over all ``components''.