Check that coordinates_min[dim] < coordinates_max[dim] (#2257)

* Check coords

* function

* Check

* Update src/meshes/abstract_tree.jl

* Apply suggestions from code review

Co-authored-by: Joshua Lampert <[email protected]>

* comment + s

---------

Co-authored-by: Joshua Lampert <[email protected]>

Author: DanielDoehring

src/meshes/abstract_tree.jl

@@ -387,13 +387,20 @@ function refine!(t::AbstractTree, cell_ids,
     return refined_original_cells
 end
 
+@inline function coordinates_min_max_check(coordinates_min, coordinates_max)
+    for dim in eachindex(coordinates_min)
+        @assert coordinates_min[dim]<coordinates_max[dim] "coordinates_min[$dim] must be smaller than coordinates_max[$dim]!"
+    end
+end
+# For the p4est and the t8code mesh we allow `coordinates_min` and `coordinates_max` to be `nothing`.
+# This corresponds to meshes constructed from analytic mapping functions.
+coordinates_min_max_check(::Nothing, ::Nothing) = nothing
+
 # Refine all leaf cells with coordinates in a given rectangular box
 function refine_box!(t::AbstractTree{NDIMS},
                      coordinates_min,
                      coordinates_max) where {NDIMS}
-    for dim in 1:NDIMS
-        @assert coordinates_min[dim]<coordinates_max[dim] "Minimum coordinates are not minimum."
-    end
+    coordinates_min_max_check(coordinates_min, coordinates_max)
 
     # Find all leaf cells within box
     cells = filter_leaf_cells(t) do cell_id

src/meshes/p4est_mesh.jl

@@ -191,6 +191,8 @@ function P4estMesh(trees_per_dimension; polydeg,
                    p4est_partition_allow_for_coarsening = true)
     @assert ((coordinates_min === nothing)===(coordinates_max === nothing)) "Either both or none of coordinates_min and coordinates_max must be specified"
 
+    coordinates_min_max_check(coordinates_min, coordinates_max)
+
     @assert count(i -> i !== nothing,
                   (mapping, faces, coordinates_min))==1 "Exactly one of mapping, faces and coordinates_min/max must be specified"
 

src/meshes/structured_mesh.jl

@@ -140,6 +140,8 @@ function StructuredMesh(cells_per_dimension, coordinates_min, coordinates_max;
                         periodicity = true)
     RealT = promote_type(eltype(coordinates_min), eltype(coordinates_max))
 
+    coordinates_min_max_check(coordinates_min, coordinates_max)
+
     mapping = coordinates2mapping(coordinates_min, coordinates_max)
     mapping_as_string = """
         coordinates_min = $coordinates_min

src/meshes/t8code_mesh.jl

@@ -427,6 +427,8 @@ function T8codeMesh(trees_per_dimension; polydeg = 1,
                     periodicity = true)
     @assert ((coordinates_min === nothing)===(coordinates_max === nothing)) "Either both or none of coordinates_min and coordinates_max must be specified"
 
+    coordinates_min_max_check(coordinates_min, coordinates_max)
+
     @assert count(i -> i !== nothing,
                   (mapping, faces, coordinates_min))==1 "Exactly one of mapping, faces and coordinates_min/max must be specified"
 

src/meshes/tree_mesh.jl

@@ -134,6 +134,8 @@ function TreeMesh(coordinates_min::NTuple{NDIMS, Real},
         end
     end
 
+    coordinates_min_max_check(coordinates_min, coordinates_max)
+
     # TreeMesh requires equal domain lengths in all dimensions
     domain_center = @. convert(RealT, (coordinates_min + coordinates_max) / 2)
     domain_length = convert(RealT, coordinates_max[1] - coordinates_min[1])