group::traits, and group::compose

gtsam/base/concepts.h

@@ -24,7 +24,8 @@ namespace traits {
  */
 //@{
 template<class T>
-struct structure_category; // specializations should be derived from one of the following tags
+struct structure_category;
+// specializations should be derived from one of the following tags
 //@}
 
 /**
@@ -32,10 +33,14 @@ struct structure_category; // specializations should be derived from one of the
  * @brief Possible values for traits::structure_category<T>::type
  */
 //@{
-struct manifold_tag {};
-struct group_tag {};
-struct lie_group_tag : public manifold_tag, public group_tag {};
-struct vector_space_tag : public lie_group_tag {};
+struct manifold_tag {
+};
+struct group_tag {
+};
+struct lie_group_tag: public manifold_tag, public group_tag {
+};
+struct vector_space_tag: public lie_group_tag {
+};
 //@}
 
 }// namespace traits
@@ -88,41 +93,51 @@ class ChartConcept {
  };
  */
 
+namespace group {
+
+template<typename G>
+G compose(const G&g, const G& h);
+
 namespace traits {
 
 /** @name Group Traits */
 //@{
-template <class Group> struct identity;
-template <class Group> struct group_flavor;
+template<class G> struct identity;
+template<class G> struct flavor;
 //@}
 
 /** @name Group Flavor Tags */
 //@{
-struct additive_group_tag {};
-struct multiplicative_group_tag {};
+struct additive_tag {
+};
+struct multiplicative_tag {
+};
 //@}
 
-} // namespace traits
+} // \ namespace traits
+} // \ namespace group
 
 /**
  * Group Concept
  */
-template<class G>
+template<typename G>
 class Group {
 public:
 
-  typedef typename traits::identity<G>::value_type identity_value_type;
-  typedef typename traits::group_flavor<G>::type group_flavor_tag;
   typedef typename traits::structure_category<G>::type structure_category_tag;
+  typedef typename group::traits::identity<G>::value_type identity_value_type;
+  typedef typename group::traits::flavor<G>::type group_flavor_tag;
 
   BOOST_CONCEPT_USAGE(Group) {
-    e = traits::identity<G>::value;
-//    BOOST_STATIC_ASSERT(boost::is_base_of<traits::group_tag,typename traits::structure_category<Group>::type>::value );
+    using group::compose;
+    BOOST_STATIC_ASSERT(
+        boost::is_base_of<traits::group_tag, structure_category_tag>::value);
+    e = group::traits::identity<G>::value;
+    pq = compose(p, q);
 //    G ip = inverse(p);
-//    G pq = compose(p, q);
 //    G d = between(p, q);
 //    test = equal(p, q);
-//    test2 = operator_usage(p, q, traits::group_flavor<Group>::type);
+//    test2 = operator_usage(p, q, group::traits::_flavor<Group>::type);
   }
 
   bool check_invariants(const G& a, const G& b) {
@@ -134,15 +149,15 @@ public:
   }
 
 private:
-  G p, q, e;
+  G e, p, q, pq, ip, d;
   bool test, test2;
 
   bool operator_usage(const G& a, const G& b,
-      traits::multiplicative_group_tag) {
+      group::traits::multiplicative_tag) {
     return equal(compose(a, b), a * b);
 
   }
-  bool operator_usage(const G& a, const G& b, traits::additive_group_tag) {
+  bool operator_usage(const G& a, const G& b, group::traits::additive_tag) {
     return equal(compose(a, b), a + b);
   }
 
@@ -184,4 +199,3 @@ class VectorSpaceConcept : public LieGroupConcept {
 
 } // namespace gtsam
 
-

gtsam/geometry/tests/testCyclic.cpp

@@ -35,17 +35,28 @@ public:
 };
 
 namespace traits {
+/// Define Cyclic to be a model of the Group concept
 template<size_t N> struct structure_category<Cyclic<N> > {
   typedef group_tag type;
 };
+} // \namespace traits
+
+namespace group {
+template<size_t N>
+Cyclic<N> compose(const Cyclic<N>&g, const Cyclic<N>& h);
+
+namespace traits {
+/// Define the trait that specifies Cyclic's identity element
 template<size_t N> struct identity<Cyclic<N> > {
   static const Cyclic<N> value;
   typedef Cyclic<N> value_type;
 };
-template<size_t N> struct group_flavor<Cyclic<N> > {
-  typedef additive_group_tag type;
+/// Define the trait that asserts Cyclic is an additive group
+template<size_t N> struct flavor<Cyclic<N> > {
+  typedef additive_tag type;
 };
 } // \namespace traits
+} // \namespace group
 
 } // \namespace gtsam
 
@@ -57,10 +68,12 @@ template<size_t N> struct group_flavor<Cyclic<N> > {
 
 namespace gtsam {
 
+namespace group {
 namespace traits {
 template<size_t N>
 const Cyclic<N> identity<Cyclic<N> >::value = Cyclic<N>(0);
 } // \namespace traits
+} // \namespace group
 
 } // \namespace gtsam
 
@@ -81,7 +94,7 @@ typedef Cyclic<6> G; // Let's use the cyclic group of order 6
 
 //******************************************************************************
 TEST(Cyclic, Concept) {
-  EXPECT_LONGS_EQUAL(0,traits::identity<G>::value);
+  EXPECT_LONGS_EQUAL(0, group::traits::identity<G>::value);
   BOOST_CONCEPT_ASSERT((Group<G>));
 }