From d5215fbed3ce177570430da7eef4be464e5382f1 Mon Sep 17 00:00:00 2001
From: Petr Krysl <pkrysl@ucsd.edu>
Date: Sat, 25 May 2024 18:50:19 -0700
Subject: [PATCH] add mesh validation function

---
 Project.toml                  |  2 +-
 src/FinEtools.jl              |  6 +++--
 src/MeshModificationModule.jl | 45 ++++++++++++++++++++++++++++++++++-
 test/test_basics.jl           | 22 ++++++++++++++++-
 4 files changed, 70 insertions(+), 5 deletions(-)

diff --git a/Project.toml b/Project.toml
index ce4cf3dc..01b1b2df 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "FinEtools"
 uuid = "91bb5406-6c9a-523d-811d-0644c4229550"
 authors = ["Petr Krysl <pkrysl@ucsd.edu>"]
-version = "8.0.22"
+version = "8.0.23"
 
 [deps]
 DataDrop = "aa547a04-dd37-49ab-8e73-656744f8a8fc"
diff --git a/src/FinEtools.jl b/src/FinEtools.jl
index 412270fc..2f3bb523 100644
--- a/src/FinEtools.jl
+++ b/src/FinEtools.jl
@@ -306,7 +306,8 @@ using .MeshModificationModule:
     distortblock,
     outer_surface_of_solid,
     reordermesh,
-    element_coloring
+    element_coloring,
+    validate_mesh
 # Exported: extraction of boundary, fusing of nodes  and merging of meshes, mesh smoothing,  node partitioning
 export meshboundary,
     fusenodes,
@@ -323,7 +324,8 @@ export meshboundary,
     distortblock,
     outer_surface_of_solid,
     reordermesh,
-    element_coloring
+    element_coloring,
+    validate_mesh
 
 using .MeshImportModule: import_NASTRAN, import_ABAQUS, import_MESH, import_H5MESH
 # Exported: mesh import functions
diff --git a/src/MeshModificationModule.jl b/src/MeshModificationModule.jl
index 985dd7fc..c678e57d 100644
--- a/src/MeshModificationModule.jl
+++ b/src/MeshModificationModule.jl
@@ -21,7 +21,7 @@ import ..FESetModule:
     subset
 import ..FENodeSetModule: FENodeSet
 import ..BoxModule: boundingbox, inflatebox!, intersectboxes, inbox
-import ..MeshSelectionModule: connectednodes, selectelem
+import ..MeshSelectionModule: connectednodes, selectelem, findunconnnodes
 import ..SurfaceNormalModule: SurfaceNormal, updatenormal!
 using Base.Sort
 using Base.Order
@@ -1357,4 +1357,47 @@ function element_coloring!(element_colors, unique_colors, color_counts, fes, n2e
     return element_colors, unique_colors, color_counts
 end
 
+"""
+    validate_mesh(fens, fes)
+
+Validate the given mesh by checking if it satisfies certain sanity criteria.
+
+# Arguments
+- `fens`: The finite element nodes of the mesh.
+- `fes`: The finite elements of the mesh.
+
+Validate finite element mesh.
+    
+A finite element mesh given by the node set and the finite element set is
+validated by checking the sanity of the numbering:
+- the node numbers need to be positive and in serial order
+- the fe connectivity needs to refer to valid nodes
+- the finite element nodes need to be connected to at least one finite element
+
+An error is reported as soon as it is detected.
+
+# Returns
+A boolean indicating whether the mesh is valid or not.
+"""
+function validate_mesh(fens, fes)
+    totnfens = count(fens)
+    for i in eachindex(fes)
+        if (max(fes.conn[i]...) > totnfens)
+            error("Wrong connectivity (refers to nonexistent node): $(fes.conn[i])")
+        end
+        if (min(fes.conn[i]...) < 1)
+            error("Wrong connectivity (refers to nonexistent node): $(fes.conn[i])")
+        end
+        if (length(unique(fes.conn[i])) != length(fes.conn[i]))
+            error("Wrong connectivity (multiply referenced node): $(fes.conn[i])")
+        end
+    end
+    connected = findunconnnodes(fens, fes)
+    if (any(connected == 0))
+        error("Unconnected nodes present: $(sum(connected==0)) total")
+    end
+    return true
+end
+
+
 end # module
diff --git a/test/test_basics.jl b/test/test_basics.jl
index b275a41e..2592251f 100644
--- a/test/test_basics.jl
+++ b/test/test_basics.jl
@@ -1,3 +1,24 @@
+module mval001
+using Test
+using FinEtools
+function test()
+    fens = FENodeSet(rand(5, 2))
+    fes = FESetT3([1 2 6; 3 4 5])
+    @test_throws ErrorException validate_mesh(fens, fes)
+    fes = FESetT3([1 2 6; -1 4 5])
+    @test_throws ErrorException validate_mesh(fens, fes)
+    fes = FESetT3([1 2 3; 0 4 5])
+    @test_throws ErrorException validate_mesh(fens, fes)
+    fes = FESetT3([1 2 3; 0 4 5])
+    @test_throws ErrorException validate_mesh(fens, fes)
+    fes = FESetT3([1 2 3; 2 4 5])
+    @test validate_mesh(fens, fes)
+    true
+end
+test()
+nothing
+end
+
 module mbas113
 using FinEtools
 using Test
@@ -3015,4 +3036,3 @@ end
 test()
 nothing
 end
-