evaluate twists of hexahedron.

git-svn-id: https://dune.mathematik.uni-freiburg.de/svn/alugrid/trunk@761 0d966ed9-3843-0410-af09-ebfb50bd7c74

misc/examples/twist.cc

+//***********************************************************************
+//
+//  Example program how to use ALUGrid. 
+//  Author: Robert Kloefkorn 
+//
+//  This little program read one of the macrogrids and generates a grid. 
+//  The  grid is refined and coarsend again. 
+//
+//***********************************************************************
+#include <iostream>
+using namespace std;
+
+// include serial part of ALUGrid 
+
+int evalVertexTwist(int twist, int vertex) 
+{
+ return (twist < 0 ?
+          (9 - vertex + twist) % 4 :
+          (vertex + twist) % 4);
+}
+
+int evalEdgeTwist(int twist, int edge) 
+{
+ return (twist < 0 ?
+              (8 - edge + twist) % 4 :
+              (edge + twist) % 4);
+}
+
+
+int main() 
+{
+  std::cout << "Hexa Vertex Twists\n";
+  for(int tw=0; tw <8; ++tw)
+  {
+    std::cout << "{"; 
+    for(int vx=0; vx<4; ++vx) 
+    {
+      std::cout << evalVertexTwist(tw-4,vx);
+      if(vx < 3) 
+      {
+        std::cout << ",";
+      }
+      else 
+      {
+        if(tw < 7)
+          std::cout << "},";
+        else 
+          std::cout << "} ";
+      }
+    }
+    std::cout << " // twist = " << tw-4 << "\n";
+  }
+  
+  std::cout << "Hexa Edge Twist \n";
+  for(int tw=0; tw <8; ++tw)
+  {
+    std::cout << "{"; 
+    for(int edge=0; edge<4; ++edge) 
+    {
+      std::cout << evalEdgeTwist(tw-4,edge);
+      if(edge < 3) 
+      {
+        std::cout << ",";
+      }
+      else 
+      {
+        if(tw < 7)
+          std::cout << "},";
+        else 
+          std::cout << "} ";
+      }
+    }
+    std::cout << " // twist = " << tw-4 << "\n";
+  }
+  return 0;
+}