Polished the code a little.

--HG--
extra : convert_revision : svn%3Afdd8eb12-d10e-0410-9acb-85c331704f74/trunk%403491

dlib/optimization/optimization_oca.h

@@ -34,7 +34,7 @@ namespace dlib
         virtual scalar_type get_C (
         ) const = 0;
 
-        virtual long num_dimensions (
+        virtual long get_num_dimensions (
         ) const = 0;
 
         virtual void get_risk (
@@ -144,11 +144,21 @@ namespace dlib
         template <
             typename matrix_type
             >
-        void operator() (
+        typename matrix_type::type operator() (
             const oca_problem<matrix_type>& problem,
             matrix_type& w
         ) const
         {
+            // make sure requires clause is not broken
+            DLIB_ASSERT(problem.get_C() > 0 &&
+                        problem.get_num_dimensions() > 0,
+                "\t void oca::operator()"
+                << "\n\t The oca_problem is invalid"
+                << "\n\t problem.get_C():              " << problem.get_C() 
+                << "\n\t problem.get_num_dimensions(): " << problem.get_num_dimensions() 
+                << "\n\t this: " << this
+                );
+
             typedef typename matrix_type::type scalar_type;
             typedef typename matrix_type::layout_type layout_type;
             typedef typename matrix_type::mem_manager_type mem_manager_type;
@@ -161,7 +171,7 @@ namespace dlib
 
             vect_type temp, alpha, w_cur;
 
-            w.set_size(problem.num_dimensions(), 1);
+            w.set_size(problem.get_num_dimensions(), 1);
             w = 0;
             w_cur = w;
 
@@ -274,6 +284,7 @@ namespace dlib
             // report current status
             problem.optimization_status(best_obj, best_obj - cp_obj, planes.size());
 
+            return best_obj;
         }
 
     private:

dlib/optimization/optimization_oca_abstract.h

@@ -59,7 +59,7 @@ namespace dlib
                 - returns the C parameter
         !*/
 
-        virtual long num_dimensions (
+        virtual long get_num_dimensions (
         ) const = 0;
         /*!
             ensures
@@ -74,7 +74,7 @@ namespace dlib
         /*!
             requires
                 - is_col_vector(current_solution) == true
-                - current_solution.size() == num_dimensions()
+                - current_solution.size() == get_num_dimensions()
             ensures
                 - #current_solution will be set to one of the following:
                     - current_solution (i.e. it won't be modified at all)
@@ -129,13 +129,17 @@ namespace dlib
         template <
             typename matrix_type
             >
-        void operator() (
+        typename matrix_type::type operator() (
             const oca_problem<matrix_type>& problem,
             matrix_type& w
         ) const;
         /*!
+            requires
+                - problem.get_C() > 0
+                - problem.get_num_dimensions() > 0
             ensures
                 - solves the given oca problem and stores the solution in #w
+                - returns the objective value at the soltuion #w
         !*/
 
         void set_epsilon (