3-NIRVANA-user-guide/3.1-Code-basics.md

@@ -358,7 +358,7 @@ Elements V of struct `GRD`:
 | `pos[3]`            | grid index of a generic block within parent block (AMR)        |
 | `posc[3]`           | grid index of a generic block within its associated superblock |
 
-A cell with index (,,) within a grid block `g` spans the domain
+A cell with index (`ix`,`iy`,`iz`) within a grid block `g` spans the domain
 \[`g->x[ix]`,`g->x[ix+1]`\]$\times$\[`g->y[iy]`,`g->y[iy+1]`\]$\times$\[`g->z[iz]`,`g->z[iz+1]`\]
 where (`g->x[ix]`,`g->y[iy]`,`g->z[iz]`) are the nodal coordinates of
 the lower cell corner. Cell-centroid coordinates locate the volume
@@ -379,7 +379,7 @@ general, is true in Cartesian geometry.
 | *xy*/*xz*-face-centroid x | `xf[ix]` | *z*<sub>`ix`+1/2</sub>                                                  | 2*Δ*<sub>`ix`</sub>*r*<sup>3</sup>/(3*Δ*<sub>`ix`</sub>*r*<sup>2</sup>) |
 | *yz*-face-centroid x      | `x[ix]`  | *z*<sub>`ix`+1/2</sub>                                                  | *r*<sub>`ix`+1/2</sub>)                                                 |
 | *xy*/*yz*-face-centroid y | `yc[iy]` | 2*Δ*<sub>`iy`</sub>*R*<sup>3</sup>/(3*Δ*<sub>`iy`</sub>*R*<sup>2</sup>) | *Δ*<sub>`iy`</sub>( *θ*cos *θ* − sin *θ*)/*Δ*<sub>`iy`</sub>cos *θ*     |
-| *xz*-face-centroid y      | `y[iy]`  | *R*<sub>`iy`+1/2</sub>                                                  | *θ*<sub>`iy`+1/2</sub>)                                                 |
+| *xz*-face-centroid y      | `y[iy]`  | *R*<sub>`iy`</sub>                                                      | *θ*<sub>`iy`</sub>)                                                     |
 | *xy*-face-centroid z      | `z[iz]`  | *ϕ*<sub>`iz`</sub>                                                      | *ϕ*<sub>`iz`</sub>                                                      |
 | *xz*/*yz*-face-centroid z | `zc[iz]` | *ϕ*<sub>`iz`+1/2</sub>                                                  | *ϕ*<sub>`iz`+1/2</sub>                                                  |
 
@@ -387,7 +387,7 @@ general, is true in Cartesian geometry.
 
 The mesh refinement algorithm relies on the oct-tree data structure of
 generic blocks (fixed size of 4 cells per direction) represented by the
-master mesh pointer `_G0` (of type `*GRD`). A generic block of
+master mesh pointer `_G0` (of type `**GRD`). A generic block of
 refinement level $l$ has cell spacings
 $(\delta x^{(l)}, \delta y^{(l)}, \delta z^{(l)})=
 (\delta x^{(0)},\delta y^{(0)},\delta z^{(0)})/2^l$ where