Coordinate Thorns

Generally coordinate thorns will allow the declaration of default coordinate systems for a dimension to be controled by parameters.

If a thorn attempts to register a default for a dimension which already has a default registered, a level 1 warning will result, and the default will be overwritten with the new default. Since the order of execution of the registration calls will in general not be specified, one must be careful when activating more than one coordinate thorn.

Coordinate systems and defaults can be changed at any time throughout a run, as can coordinate properties. In general these are set at CCTK_WRAGH and CCTK_BASEGRID, respectively.

The coordinate thorns are responsible for filling out the portions of the coordinate and coordinate system tables that are not written by the registration routines. See sections A3.7.1 and A3.7.2.