2 files changed, 38 insertions, 2 deletions
diff --git a/lib/include/graph.hpp b/lib/include/graph.hpp
index 032a4d1..1714dc2 100644
--- a/lib/include/graph.hpp
+++ b/lib/include/graph.hpp
@@ -42,5 +42,6 @@ class graph {
     graph(unsigned n, double a, std::mt19937& rng);
 
     void helper(unsigned n, std::mt19937& rng);
+    graph const rotate();
 };
 
diff --git a/lib/src/graph.cpp b/lib/src/graph.cpp
index 364f339..974d3b3 100644
--- a/lib/src/graph.cpp
+++ b/lib/src/graph.cpp
@@ -157,9 +157,8 @@ graph::graph(unsigned n, double a, std::mt19937& rng) {
   this->helper(n, rng);
 }
 
-void graph::helper(unsigned n, std::mt19937& rng) {
+void graph::helper(unsigned nv, std::mt19937& rng) {
   std::uniform_real_distribution<double> d(0.0, 1.0);
-  unsigned nv = n;
   vertices.resize(nv);
 
   // the coordinates of the lattice, from which a delaunay triangulation
@@ -363,3 +362,39 @@ void graph::helper(unsigned n, std::mt19937& rng) {
   jcv_diagram_free(&diagram);
 }
 
+graph::coordinate reverse(const graph::coordinate &x) {
+  return {x.y, x.x};
+}
+
+graph const graph::rotate() {
+  graph g2(*this);
+
+  for (graph::vertex &v : g2.vertices) {
+    v.r = reverse(v.r);
+    for (graph::coordinate &r : v.polygon) {
+      r = reverse(r);
+    }
+  }
+
+  for (graph::edge &e : g2.edges) {
+    e.r = reverse(e.r);
+    e.crossings = {e.crossings[1], e.crossings[0]};
+  }
+
+  for (graph::vertex &v : g2.dual_vertices) {
+    v.r = reverse(v.r);
+    for (graph::coordinate &r : v.polygon) {
+      r = reverse(r);
+    }
+  }
+
+  for (graph::edge &e : g2.dual_edges) {
+    e.r = reverse(e.r);
+    e.crossings = {e.crossings[1], e.crossings[0]};
+  }
+
+  g2.L = reverse(g2.L);
+
+  return g2;
+}
+