Small bugfix in findElInfoAtPoint, thanks to Francisco.

AMDiS/src/Mesh.cc

@@ -674,10 +674,22 @@ namespace AMDiS {
 
     mel_info->fillMacroInfo(mel);
 
+    // We have the care about not to visite a macro element twice. In this case the
+    // function would end up in an infinite loop. If a macro element is visited a 
+    // second time, what can happen with periodic boundary conditions, the point is
+    // not within the mesh!
+    std::set<int> macrosVisited;
+    macrosVisited.insert(mel->getIndex());
+
     int k;
     while ((k = mel_info->worldToCoord(xy, &lambda)) >= 0) {
       if (mel->getNeighbour(k)) {
 	mel = mel->getNeighbour(k);
+	mel = mel->getNeighbour(k);
+	if (macrosVisited.count(mel->getIndex()))
+	  return false;
+
+	macrosVisited.insert(mel->getIndex());
 	mel_info->fillMacroInfo(mel);
 	continue;
       }