Fixed the code so it works with sparse vectors.

dlib/svm/structural_graph_labeling_trainer.h

@@ -147,13 +147,49 @@ namespace dlib
             matrix<double,0,1> w;
             solver(prob, w, prob.get_num_edge_weights());
 
-            vector_type edge_weights = rowm(w,range(0, prob.get_num_edge_weights()-1));
-            vector_type node_weights = rowm(w,range(prob.get_num_edge_weights(),w.size()-1));
+            vector_type edge_weights;
+            vector_type node_weights;
+            populate_weights(w, edge_weights, node_weights, prob.get_num_edge_weights());
             return graph_labeler<vector_type>(edge_weights, node_weights);
         }
 
     private:
 
+        template <typename T>
+        typename enable_if<is_matrix<T> >::type populate_weights (
+            const matrix<double,0,1>& w,
+            T& edge_weights,
+            T& node_weights,
+            long split_idx
+        ) const
+        {
+            edge_weights = rowm(w,range(0, split_idx-1));
+            node_weights = rowm(w,range(split_idx,w.size()-1));
+        }
+
+        template <typename T>
+        typename disable_if<is_matrix<T> >::type populate_weights (
+            const matrix<double,0,1>& w,
+            T& edge_weights,
+            T& node_weights,
+            long split_idx
+        ) const
+        {
+            edge_weights.clear();
+            node_weights.clear();
+            for (long i = 0; i < split_idx; ++i)
+            {
+                if (w(i) != 0)
+                    edge_weights.insert(edge_weights.end(), std::make_pair(i,w(i)));
+            }
+            for (long i = split_idx; i < w.size(); ++i)
+            {
+                if (w(i) != 0)
+                    node_weights.insert(node_weights.end(), std::make_pair(i-split_idx,w(i)));
+            }
+        }
+
+
         double C;
         oca solver;
         double eps;

dlib/svm/structural_svm_graph_labeling_problem.h

@@ -12,6 +12,7 @@
 #include <iterator>
 #include "structural_svm_problem_threaded.h"
 #include "../graph.h"
+#include "sparse_vector.h"
 
 // ----------------------------------------------------------------------------------------
 
@@ -170,36 +171,22 @@ namespace dlib
                     "\t structural_svm_graph_labeling_problem::structural_svm_graph_labeling_problem()"
                     << "\n\t invalid inputs were given to this function");
 
+            using namespace dlib::sparse_vector;
 
-            // Figure out how many dimensions are in a node vector.  Just pick
-            // the first node we find and use it as the representative example.
-            node_dims = 0;
-            for (unsigned long i = 0; i < samples.size(); ++i)
-            {
-                if (samples[i].number_of_nodes() > 0)
-                {
-                    node_dims = samples[i].node(0).data.size();
-                    break;
-                }
-            }
 
-            // Figure out how many dimensions are in an edge vector.  Just pick
-            // the first edge we find and use it as the representative example.
+            // figure out how many dimensions are in the node and edge vectors.
+            node_dims = 0;
             edge_dims = 0;
             for (unsigned long i = 0; i < samples.size(); ++i)
             {
                 for (unsigned long j = 0; j < samples[i].number_of_nodes(); ++j)
                 {
-                    if (samples[i].node(j).number_of_neighbors() != 0)
+                    node_dims = std::max(node_dims,(long)max_index_plus_one(samples[i].node(j).data));
+                    for (unsigned long n = 0; n < samples[i].node(j).number_of_neighbors(); ++n)
                     {
-                        edge_dims = samples[i].node(j).edge(0).size();
-                        break;
+                        edge_dims = std::max(edge_dims, (long)max_index_plus_one(samples[i].node(j).edge(n)));
                     }
                 }
-
-                // if we found an edge then stop
-                if (edge_dims != 0)
-                    break;
             }
         }
 
@@ -270,9 +257,9 @@ namespace dlib
             unsigned long offset 
         ) const
         {
-            for (unsigned long i = 0; i < vect.size(); ++i)
+            for (typename T::const_iterator i = vect.begin(); i != vect.end(); ++i)
             {
-                psi.push_back(std::make_pair(vect[i].first+offset, vect[i].second));
+                psi.insert(psi.end(), std::make_pair(i->first+offset, i->second));
             }
         }
 
@@ -282,9 +269,9 @@ namespace dlib
             const T& vect
         ) const
         {
-            for (unsigned long i = 0; i < vect.size(); ++i)
+            for (typename T::const_iterator i = vect.begin(); i != vect.end(); ++i)
             {
-                psi.push_back(std::make_pair(vect[i].first, -vect[i].second));
+                psi.insert(psi.end(), std::make_pair(i->first, -i->second));
             }
         }