Improve docstring of RegularGrid

Author: juliohm

src/domains/meshes/regulargrid.jl

@@ -3,32 +3,26 @@
 # ------------------------------------------------------------------
 
 """
-    RegularGrid(dims, origin, spacing)
+    RegularGrid(start, finish; dims=dims)
 
-A regular grid with dimensions `dims`, lower left corner at `origin`
-and cell spacing `spacing`. The three arguments must have the same length.
+A regular grid from `start` point to `finish` point with dimensions `dims`.
+The number of dimensions must match the number of coordinates of the points.
 
-    RegularGrid(dims, origin, spacing, offset)
-
-A regular grid with dimensions `dims`, with lower left corner of element
-`offset` at `origin` and cell spacing `spacing`.
-
-    RegularGrid(start, finish, dims=dims)
+    RegularGrid(start, finish, spacing)
 
-Alternatively, construct a regular grid from a `start` point to a `finish`
-with dimensions `dims`.
+Alternatively, construct a regular grid from `start` point to `finish` point
+by specifying the `spacing` for each dimension.
 
-    RegularGrid(start, finish, spacing)
+    RegularGrid(dims, origin, spacing, offset=(1, 1, ...))
 
-Alternatively, construct a regular grid from a `start` point to a `finish`
-point using a given `spacing`.
+Alternatively, construct a regular grid with dimensions `dims`, lower left
+corner of `offset` element at `origin` point, and `spacing` for each dimension.
 
     RegularGrid(dims)
-    RegularGrid(dim1, dim2, ...)
+    RegularGrid(dim₁, dim₂, ...)
 
-Finally, a regular grid can be constructed by only passing the dimensions
-`dims` as a tuple, or by passing each dimension `dim1`, `dim2`, ... separately.
-In this case, the origin and spacing default to (0,0,...) and (1,1,...).
+Alternatively, construct a regular grid with dimensions `dims = (dim₁, dim₂, ...)`,
+origin point with coordinates `(0m, 0m, ...)` and spacing equal to `(1m, 1m, ...)`.
 
 ## Examples
 
@@ -38,10 +32,11 @@ Create a 3D grid with 100x100x50 hexahedrons:
 julia> RegularGrid(100, 100, 50)
 ```
 
-Create a 2D grid with 100 x 100 quadrangles and origin at (10.0, 20.0):
+Create a 2D grid from point (0.0, 0.0) to point (10.0, 20.0)
+with spacing equal to (1.0, 2.0):
 
 ```julia
-julia> RegularGrid((100, 100), (10.0, 20.0), (1.0, 1.0))
+julia> RegularGrid((0.0, 0.0), (10.0, 20.0), (1.0, 2.0))
 ```
 
 Create a 1D grid from -1 to 1 with 100 segments: