Home

Welcome to the GHEX wiki!

Generic exascale-ready library for halo-exchange operations

Here we shall describe the concepts as we go and try to keep them up to date.

Grid description / Domain decomposition

When working with generic data originating from different physical applications it is necessary to be able to describe the topology and decomposition of the relevant data. This description shall be gathered in a generic grid description which is able to handle different meshes and their domain decompositions. Some examples are

• 2-Dimensional regular grids + vertical dimension (regional weather and climate simulations)
  • decomposition along first or first and second dimension
• N-Dimensional regular grids (hypercube)
  • decomposition along n <= N dimensions
• inflated icosahedral surface mesh + vertical dimension (global weather and climate simulations)
  • decomposition?
• inflated cube surface mesh + vertical dimension (global weather and climate simulations)
  • decomposition?
• completely unstructured mesh in N>2 dimensions
  • decomposition along space filling curve?

In general, we need a concept to describe

• the coordinate/location for any given cell (and possibly edge for staggered grids),
• the portion of the topology/mesh that is local and
• a way to find the neighbour information
  • this can be either shell wise (face neighbours of cells) or
  • by specifying halos (only for regular grids)