diff --git a/src/mykdtree.hpp b/src/mykdtree.hpp
index 27d66ae..bf1eaa0 100644
--- a/src/mykdtree.hpp
+++ b/src/mykdtree.hpp
@@ -136,7 +136,13 @@ namespace CosmoTool {
     void setPeriodic(bool on, CoordType replicate)
      {
        periodic = on;
-       this->replicate = replicate;
+       std::fill(this->replicate, this->replicate+N, replicate);
+     }
+
+    void setPeriodic(bool on, const coords& replicate)
+     {
+       periodic = on;
+       std::copy(replicate, replicate+N, this->replicate);
      }
 
     uint32_t getIntersection(const coords& x, CoordType r, 
@@ -193,7 +199,7 @@ namespace CosmoTool {
     Cell *base_cell;
 
     bool periodic;
-    CoordType replicate;
+    coords replicate;
 
     Node *buildTree(Cell **cell0,
 		    uint32_t NumCells,
diff --git a/src/replicateGenerator.hpp b/src/replicateGenerator.hpp
index fd7035f..4d89050 100644
--- a/src/replicateGenerator.hpp
+++ b/src/replicateGenerator.hpp
@@ -46,18 +46,29 @@ namespace CosmoTool
   {
   public:
     typedef Coord Coords[N];
-    Coord replicate;
+    Coords replicate;
 
     ReplicateGenerator(const Coords& x, Coord shift)
     {
       face = 0; 
-      replicate = shift;
+      std::fill(replicate, replicate+N, shift);
       numFaces = spower<N,long>(3);
       std::copy(x, x+N, x_base);
       if (!next())
 	abort();
     }
 
+    ReplicateGenerator(const Coords& x, Coords& shift)
+    {
+      face = 0;
+      std::copy(shift, shift+N, replicate);
+      numFaces = spower<N,long>(3);
+      std::copy(x, x+N, x_base);
+      if (!next())
+        abort();
+    }
+
+
     bool next()
     {
       if (face == numFaces)
@@ -72,7 +83,7 @@ namespace CosmoTool
           int c_face;
           c_face = q_face % 3;
           q_face /= 3;
-          x_shifted[i] = x_base[i] + (c_face-1)*replicate;
+          x_shifted[i] = x_base[i] + (c_face-1)*replicate[i];
           no_move = no_move && (c_face == 1);
         }
       if (no_move)