\sa lemon::concepts::Path

 \sa \ref concepts::Path "Path concept"

 */

 /**

 @defgroup heaps Heap Structures

 @ingroup datas

 \brief %Heap structures implemented in LEMON.

 This group contains the heap structures implemented in LEMON.

 LEMON provides several heap classes. They are efficient implementations

 of the abstract data type \e priority \e queue. They store items with

 specified values called \e priorities in such a way that finding and

 removing the item with minimum priority are efficient.

 The basic operations are adding and erasing items, changing the priority

 of an item, etc.

 Heaps are crucial in several algorithms, such as Dijkstra and Prim.

 The heap implementations have the same interface, thus any of them can be

 used easily in such algorithms.

 \sa \ref concepts::Heap "Heap concept"

 */

 /**

 @defgroup matrices Matrices

 @ingroup datas

 \brief Two dimensional data storages implemented in LEMON.

 This group contains two dimensional data storages implemented in LEMON.