Fixed VariableIndex deep copy

gtsam/inference/VariableIndex.cpp

@@ -23,6 +23,20 @@ namespace gtsam {
 
 using namespace std;
 
+/* ************************************************************************* */
+VariableIndex::VariableIndex(const VariableIndex& other) :
+    index_(indexUnpermuted_) {
+  *this = other;
+}
+
+/* ************************************************************************* */
+VariableIndex& VariableIndex::operator=(const VariableIndex& rhs) {
+  index_ = rhs.index_;
+  nFactors_ = rhs.nFactors_;
+  nEntries_ = rhs.nEntries_;
+  return *this;
+}
+
 /* ************************************************************************* */
 void VariableIndex::permute(const Permutation& permutation) {
 #ifndef NDEBUG

gtsam/inference/VariableIndex.h

@@ -70,6 +70,16 @@ public:
    */
   template<class FactorGraph> VariableIndex(const FactorGraph& factorGraph);
 
+  /**
+   * Copy constructor
+   */
+  VariableIndex(const VariableIndex& other);
+
+  /**
+   * Assignment operator
+   */
+  VariableIndex& operator=(const VariableIndex& rhs);
+
 	/// @}
 	/// @name Standard Interface
 	/// @{
@@ -127,7 +137,6 @@ public:
    */
   template<typename CONTAINER, class FactorGraph> void remove(const CONTAINER& indices, const FactorGraph& factors);
 
-
   /**
    * Apply a variable permutation.  Does not rearrange data, just permutes
    * future lookups by variable.

gtsam/inference/tests/testVariableIndex.cpp

@@ -75,7 +75,41 @@ TEST(VariableIndex, remove) {
   actual.remove(indices, fg1);
 
   CHECK(assert_equal(expected, actual));
+}
 
+/* ************************************************************************* */
+TEST(VariableIndex, deep_copy) {
+
+  SymbolicFactorGraph fg1, fg2;
+  fg1.push_factor(0, 1);
+  fg1.push_factor(0, 2);
+  fg1.push_factor(5, 9);
+  fg1.push_factor(2, 3);
+  fg2.push_factor(1, 3);
+  fg2.push_factor(2, 4);
+  fg2.push_factor(3, 5);
+  fg2.push_factor(5, 6);
+
+  // Create original graph and VariableIndex
+  SymbolicFactorGraph fgOriginal; fgOriginal.push_back(fg1); fgOriginal.push_back(fg2);
+  VariableIndex original(fgOriginal);
+  VariableIndex expectedOriginal(fgOriginal);
+
+  // Create a factor graph containing only the factors from fg2 and with null
+  // factors in the place of those of fg1, so that the factor indices are correct.
+  SymbolicFactorGraph fg2removed(fgOriginal);
+  fg2removed.remove(0); fg2removed.remove(1); fg2removed.remove(2); fg2removed.remove(3);
+  VariableIndex expectedRemoved(fg2removed);
+
+  // Create a clone and modify the clone - the original should not change
+  VariableIndex clone(original);
+  vector<size_t> indices;
+  indices.push_back(0); indices.push_back(1); indices.push_back(2); indices.push_back(3);
+  clone.remove(indices, fg1);
+
+  // When modifying the clone, the original should have stayed the same
+  EXPECT(assert_equal(expectedOriginal, original));
+  EXPECT(assert_equal(expectedRemoved, clone));
 }
 
 /* ************************************************************************* */