Cactus Code Thorn CarpetReduce Author(s) : Erik Schnetter Maintainer(s): Erik Schnetter Licence : GPLv2+ -------------------------------------------------------------------------- 1. Purpose This thorn provides parallel reduction operators for Carpet. This thorn now uses a weight function. This makes it possible to perform physically meaningful spatial reduction operations. The weight is 1 for all "normal" grid points. The weight is set to 0 on symmetry and possible the outer boundary, and it might be set to 1/2 on the edge of the boundary. Setting this depends on the coordinate thorn, and currently works only when the coordinates are defined via CoordBase. The weight is also reduced or set to 0 on coarser grids that are overlaid by finer grid. The weight should also be reduced or set to 0 near and in excised regions. This should happen in conjunction with an excision boundary thorn. This weigth function should probably be extracted into its own thorn MaskBase, so that many thorns can easily operate on it.