From fa023937187ccf50c6b5c326a9f656aecb3e8dc1 Mon Sep 17 00:00:00 2001
From: Jukka Aho <ahojukka5@gmail.com>
Date: Fri, 21 Nov 2025 00:31:09 +0200
Subject: [PATCH] refactor(topology): Update Quadrilateral
 reference_coordinates to SVector of Vec
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- Changed Quad4: tuple of tuples → SVector of Vec{2,Float64}
- Added Quad8: SVector with 4 corners + 4 edge midpoints
- Added Quad9: SVector with 4 corners + 4 edge midpoints + 1 center node
- All return SVector(Vec{2}(...), ...) format with comments
---
 src/topology/quadrilaterals.jl | 34 +++++++++++++++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

diff --git a/src/topology/quadrilaterals.jl b/src/topology/quadrilaterals.jl
index bb46c20..c3250e2 100644
--- a/src/topology/quadrilaterals.jl
+++ b/src/topology/quadrilaterals.jl
@@ -21,7 +21,39 @@ nnodes(::Quadrilateral{N}) where {N} = N
 dim(::Quadrilateral{N}) where {N} = 2
 
 function reference_coordinates(::Quadrilateral{4})
-    return ((-1.0, -1.0), (1.0, -1.0), (1.0, 1.0), (-1.0, 1.0))
+    return SVector(
+        Vec{2,Float64}((-1.0, -1.0)),
+        Vec{2,Float64}((1.0, -1.0)),
+        Vec{2,Float64}((1.0, 1.0)),
+        Vec{2,Float64}((-1.0, 1.0))
+    )
+end
+
+function reference_coordinates(::Quadrilateral{8})
+    return SVector(
+        Vec{2,Float64}((-1.0, -1.0)),  # N1: Corner
+        Vec{2,Float64}((1.0, -1.0)),   # N2: Corner
+        Vec{2,Float64}((1.0, 1.0)),    # N3: Corner
+        Vec{2,Float64}((-1.0, 1.0)),   # N4: Corner
+        Vec{2,Float64}((0.0, -1.0)),   # N5: Edge midpoint
+        Vec{2,Float64}((1.0, 0.0)),    # N6: Edge midpoint
+        Vec{2,Float64}((0.0, 1.0)),    # N7: Edge midpoint
+        Vec{2,Float64}((-1.0, 0.0))    # N8: Edge midpoint
+    )
+end
+
+function reference_coordinates(::Quadrilateral{9})
+    return SVector(
+        Vec{2,Float64}((-1.0, -1.0)),  # N1: Corner
+        Vec{2,Float64}((1.0, -1.0)),   # N2: Corner
+        Vec{2,Float64}((1.0, 1.0)),    # N3: Corner
+        Vec{2,Float64}((-1.0, 1.0)),   # N4: Corner
+        Vec{2,Float64}((0.0, -1.0)),   # N5: Edge midpoint
+        Vec{2,Float64}((1.0, 0.0)),    # N6: Edge midpoint
+        Vec{2,Float64}((0.0, 1.0)),    # N7: Edge midpoint
+        Vec{2,Float64}((-1.0, 0.0)),   # N8: Edge midpoint
+        Vec{2,Float64}((0.0, 0.0))     # N9: Center node
+    )
 end
 
 function edges(::Quadrilateral{N}) where {N}