Cell Indexing Semantics

Introduction

One very central data structure in MaMiCo's coupling process are CouplingCells. These cells build a bridge between the interal storage of physical quantities of the two coupled solver types.
They can thus be found in many different contexts throughout the entire coupling procedure. To assign them a spatial location, they usually come together with some form of indexing.
We try to push the following naming conventions for that in order to reduce error and increase code readability.

Conventions

1. linear means one-dimensional indexing using unsigned integer values.
   vector means indexing using vectors with one entry per spatial direction of the scenario. Note that vector indices may be non-negative e.g. when refering to a superset of the domain.
2. global means indexing relative to the entire domain on all MD MPI ranks.
   local means indexing corresponding to cells on this MD MPI rank only.

Please refer to the Index Cheatsheet for more information on indexing.