4-CAIVS-user-guide/4.2-User-interfaces.md

@@ -389,6 +389,15 @@ following physical variables:
   `ic`    tracers counter                     0...`_C.tracer`-1
   `it`    testfield fluctuations counter      0...`_C.testfields`-1
 
+| index | meaning                                 | range                 |
+|:------|:----------------------------------------|:----------------------|
+| `ix`  | `g`-index in *x*-direction              | 0...`g->nx`           |
+| `iy`  | `g`-index in *y*-direction              | 0...`g->ny`           |
+| `iz`  | `g`-index in *z*-direction              | 0...`g->nz`           |
+| `is`  | species counter                         | 0...`_C.species`-1    |
+| `ic`  | tracers counter                         | 0...`_C.tracer`-1     |
+| `it`  | testfield fluctuation variables counter | 0...`_C.testfields`-1 |
+
 `_C.species`, `_C.tracer` and `_C.testfields` are NIRVANA parameters
 (cf. [NIRVANA: Specification of main
 parameters](https://gitlab.aip.de/ziegler/NIRVANA/-/wikis/3-NIRVANA-user-guide/3.2-User-interfaces#specification-of-main-simulation-parameters))