Correct key index issue with metis ordering

gtsam/inference/MetisIndex-inl.h

@@ -29,7 +29,7 @@ namespace gtsam {
     {
         std::map<int, FastSet<int> > adjMap;
         std::map<int, FastSet<int> >::iterator adjMapIt;
-        std::set<int> values;
+        std::set<Key> keySet;
         
         /* ********** Convert to CSR format ********** */
         // Assuming that vertex numbering starts from 0 (C style),
@@ -44,17 +44,22 @@ namespace gtsam {
                 if (k1 != k2)
                   adjMap[k1].insert(adjMap[k1].end(), k2); // Insert at the end
               }
-              values.insert(values.end(), k1); // Keep a track of all unique values
+              keySet.insert(keySet.end(), k1); // Keep a track of all unique keySet
             }
           }
         }
 
-        // Number of values referenced in this factorgraph
-        nValues_ = values.size();
-        
+        // Number of keys referenced in this factor graph
+        nKeys_ = keySet.size();
+
+		
+		// Starting with a nonzero key crashes METIS
+		// Find the smallest key in the graph
+		size_t minKey = *keySet.begin(); // set is ordered
+		
         xadj_.push_back(0);// Always set the first index to zero
         for (adjMapIt = adjMap.begin(); adjMapIt != adjMap.end(); ++adjMapIt) {
-            std::vector<int> temp;
+            std::vector<Key> temp;
             // Copy from the FastSet into a temporary vector
             std::copy(adjMapIt->second.begin(), adjMapIt->second.end(), std::back_inserter(temp));
             // Insert each index's set in order by appending them to the end of adj_
@@ -62,6 +67,11 @@ namespace gtsam {
             //adj_.push_back(temp);
             xadj_.push_back(adj_.size());
         }
+
+		// Normalize, subtract the smallest key
+		std::transform(adj_.begin(), adj_.end(), adj_.begin(), std::bind2nd(std::minus<size_t>(), minKey));
+
+
     }
 
 }

gtsam/inference/MetisIndex.h

@@ -43,18 +43,18 @@ public:
 private:
     FastVector<int> xadj_; // Index of node's adjacency list in adj
     FastVector<int>  adj_; // Stores ajacency lists of all nodes, appended into a single vector
-    size_t nFactors_;     // Number of factors in the original factor graph
-    size_t nValues_;      // 
+    size_t nFactors_;      // Number of factors in the original factor graph
+    size_t nKeys_;         // 
 
 public:
     /// @name Standard Constructors
     /// @{
 
     /** Default constructor, creates empty MetisIndex */
-    MetisIndex() : nFactors_(0), nValues_(0) {}
+    MetisIndex() : nFactors_(0), nKeys_(0) {}
 
     template<class FG>
-    MetisIndex(const FG& factorGraph) : nFactors_(0), nValues_(0) {
+    MetisIndex(const FG& factorGraph) : nFactors_(0), nKeys_(0) {
         augment(factorGraph); }
 
     ~MetisIndex(){}
@@ -69,9 +69,9 @@ public:
     template<class FACTOR>
     void augment(const FactorGraph<FACTOR>& factors);
 
-    std::vector<int> xadj() const { return xadj_; }
-    std::vector<int>  adj() const { return  adj_; }
-    size_t        nValues() const { return nValues_; }
+    std::vector<int> xadj() const { return  xadj_; }
+    std::vector<int>  adj() const { return   adj_; }
+    size_t        nValues() const { return nKeys_; }
 
     /// @}
 };

gtsam/inference/tests/testOrdering.cpp

@@ -139,7 +139,27 @@ TEST(Ordering, csr_format_2) {
   EXPECT(adjExpected.size() == mi.adj().size());
   EXPECT(adjExpected == mi.adj());
 
-  //Ordering metis = Ordering::METIS(sfg);
+}
+/* ************************************************************************* */
+
+TEST(Ordering, csr_format_3) {
+  SymbolicFactorGraph sfg;
+
+  sfg.push_factor(100);
+  sfg.push_factor(100, 101);
+  sfg.push_factor(101, 102);
+  sfg.push_factor(102, 103);
+  sfg.push_factor(103, 104);
+  sfg.push_factor(104, 101);
+
+  MetisIndex mi(sfg);
+
+  vector<int> xadjExpected{ 0, 1, 4, 6, 8, 10 };
+  vector<int> adjExpected{ 1, 0, 2, 4, 1, 3, 2, 4, 1, 3 };
+
+  EXPECT(xadjExpected == mi.xadj());
+  EXPECT(adjExpected.size() == mi.adj().size());
+  EXPECT(adjExpected == mi.adj());
 
 }