I am trying to learn ElmerGrid .grd file syntax for parametric simulations in Elmer multiphysics. So far I have realised that the nD space (1 < n <3 ) is divided into subcells (squares) and then materials are assigned to them. But I can't understand how Geometry Mappings work. for example the code below generates a square with a highth of 1 and width of 5:

Code: Select all

```
***** ElmerGrid input file for structured grid generation *****
Version = 210903
Coordinate System = Cartesian 2D
Subcell Divisions in 2D = 1 1
Subcell Limits 1 = 0 5
Subcell Limits 2 = 0 1
Material Structure in 2D
1
End
Materials Interval = 1 1
```

shape 1 below:

and the geometry mapping below maps it to 2:

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```
Geometry Mappings
! mode line limits(2) Np params(Np)
1 0 1.0 1.0 8 0.0 0.1 1.0 -0.1 3.0 0.1 5.0 -0.1
5 1 1.0 1.0 4 0.0 5.0 3.0 -0.3
End
```

I have read section "2.3 Mapping modes" of ElmerGrid manual several times but I can't get my head around it. I can't understand the anatomy of the syntax. what those columns "mode", "line", "limits(2)", "Np" "params(Np)" and numbers blow them mean? maybe there are more documentations with details explaining the the syntax?