2 files changed, 40 insertions, 2 deletions
diff --git a/Carpet/CarpetLib/src/bboxset.cc b/Carpet/CarpetLib/src/bboxset.cc
index 7ffd61699..a830c0b73 100644
--- a/Carpet/CarpetLib/src/bboxset.cc
+++ b/Carpet/CarpetLib/src/bboxset.cc
@@ -464,7 +464,9 @@ bboxset<T,D> bboxset<T,D>::pseudo_inverse (const int n) const {
 }
 
 template<typename T, int D>
-bboxset<T,D> bboxset<T,D>::expand (const vect<T,D>& lo, const vect<T,D>& hi) const {
+bboxset<T,D> bboxset<T,D>::expand (const vect<T,D>& lo, const vect<T,D>& hi)
+  const
+{
   // We don't know (yet?) how to shrink a set
   assert (all (lo>=0 and hi>=0));
   bboxset res;
@@ -475,6 +477,27 @@ bboxset<T,D> bboxset<T,D>::expand (const vect<T,D>& lo, const vect<T,D>& hi) con
 }
 
 template<typename T, int D>
+bboxset<T,D> bboxset<T,D>::expand (const vect<T,D>& lo, const vect<T,D>& hi,
+                                   const vect<T,D>& denom) const
+{
+  assert (all(denom > vect<T,D>(0)));
+  bboxset res;
+  if (all (lo == -hi)) {
+    // Special case for shifting, since this is faster
+    for (const_iterator bi=begin(); bi!=end(); ++bi) {
+      res += (*bi).expand(lo,hi,denom);
+    }
+  } else {
+    // We don't know (yet?) how to shrink a set
+    assert (all ((lo>=0 and hi>=0) or (lo == hi)));
+    for (const_iterator bi=begin(); bi!=end(); ++bi) {
+      res |= (*bi).expand(lo,hi,denom);
+    }
+  }
+  return res;
+}
+
+template<typename T, int D>
 bboxset<T,D> bboxset<T,D>::expanded_for (const box& b) const {
   bboxset res;
   for (const_iterator bi=begin(); bi!=end(); ++bi) {
diff --git a/Carpet/CarpetLib/src/bboxset.hh b/Carpet/CarpetLib/src/bboxset.hh
index 5624ef4b1..23b2dc18c 100644
--- a/Carpet/CarpetLib/src/bboxset.hh
+++ b/Carpet/CarpetLib/src/bboxset.hh
@@ -142,11 +142,26 @@ public:
   /** Find the pseudo-inverse.  */
   bboxset pseudo_inverse (const int n) const;
   
-  /** Expand (enlarge) the bbox by multiples of the stride.  */
+  /** Expand (enlarge) the bboxset by multiples of the stride.  */
   bboxset expand (const vect<T,D>& lo, const vect<T,D>& hi) const;
   bboxset expand (const vect<vect<T,D>,2>& lohi) const
   { return expand (lohi[0], lohi[1]); }
   
+  /** Shift the bboxset by multiples of the stride.  */
+  bboxset shift (const vect<T,D>& v) const
+  { return expand (-v, v); }
+  
+  /** Expand (enlarge) the bboxset by multiples of a fraction of the
+      stride.  */
+  bboxset expand (const vect<T,D>& lo, const vect<T,D>& hi,
+                  const vect<T,D>& denom) const;
+  bboxset expand (const vect<vect<T,D>,2>& lohi, const vect<T,D>& denom) const
+  { return expand (lohi[0], lohi[1], denom); }
+  
+  /** Shift the bboxset by multiples of a fraction of the stride.  */
+  bboxset shift (const vect<T,D>& v, const vect<T,D>& denom) const
+  { return expand (-v, v, denom); }
+  
   /** Find the smallest b-compatible box around this bbox.
       ("compatible" means having the same stride.)  */
   bboxset expanded_for (const box& b) const;