Add iterator over all neighbors for cells.

dccrg.hpp

@@ -4330,6 +4330,7 @@ template <
 	if given error_cell.
 	*/
 	// TODO: make private?
+	// TODO: should same neighbor appear several times in returned list?
 	std::vector<
 		std::pair<
 			uint64_t,
@@ -7365,10 +7366,18 @@ template <
 		uint64_t id = error_cell;
 		Cell_Data* data = nullptr;
 		Iterator_Storage<Neighbors_Item>
-			//! iterator to cells considered as neighbor by this cell
+			/*!
+			iterator to cells considered as neighbor by this cell,
+			may (and probably does) overlap with neighbors_to
+			*/
 			neighbors_of,
-			//! iterator to cells that consider this one as neighbor
-			neighbors_to;
+			/*!
+			iterator to cells that consider this one as neighbor,
+			may (and probably does) overlap with neighbors_of
+			*/
+			neighbors_to,
+			//! iterates over both neighbors_of and neighbors_to
+			all_neighbors;
 
 		friend bool operator < (const Cells_Item& a, const Cells_Item& b)
 		{
@@ -11573,10 +11582,12 @@ template <
 		}
 
 		for (size_t i = 0; i < cells.size(); i++) {
-			cells[i].neighbors_of.begin_ =
-			cells[i].neighbors_of.end_   =
-			cells[i].neighbors_to.begin_ =
-			cells[i].neighbors_to.end_   = neighbors.cbegin();
+			cells[i].neighbors_of.begin_  =
+			cells[i].neighbors_of.end_    =
+			cells[i].neighbors_to.begin_  =
+			cells[i].neighbors_to.end_    =
+			cells[i].all_neighbors.begin_ =
+			cells[i].all_neighbors.end_   = neighbors.cbegin();
 			std::advance(
 				cells[i].neighbors_of.begin_,
 				nr_neighbors[i][0]
@@ -11593,6 +11604,14 @@ template <
 				cells[i].neighbors_to.end_,
 				nr_neighbors[i][0] + nr_neighbors[i][1] + nr_neighbors[i][2] + nr_neighbors[i][3]
 			);
+			std::advance(
+				cells[i].all_neighbors.begin_,
+				nr_neighbors[i][0]
+			);
+			std::advance(
+				cells[i].all_neighbors.end_,
+				nr_neighbors[i][0] + nr_neighbors[i][1] + nr_neighbors[i][2] + nr_neighbors[i][3]
+			);
 		}
 
 		// update iterators

tests/iterators/project_makefile

@@ -64,7 +64,7 @@ tests/iterators/test1.mtst: \
 tests/iterators/test2.exe: \
   tests/iterators/test2.cpp \
   $(TESTS_ITERATORS_COMMON_DEPS)
-	$(TESTS_ITERATORS_COMPILE_COMMAND)
+	$(TESTS_ITERATORS_COMPILE_COMMAND) -std=c++14
 
 tests/iterators/test2.tst: \
   tests/iterators/test2.exe

tests/iterators/test2.cpp

@@ -107,6 +107,21 @@ int main(int argc, char* argv[])
 				return EXIT_FAILURE;
 			}
 
+			// check all_neighbors
+			if (not std::equal(
+				cell.neighbors_of.begin(),
+				cell.neighbors_to.end(),
+				cell.all_neighbors.begin(),
+				[](const auto& first, const auto& second){
+					return first.id == second.id;
+				}
+			)) {
+				cerr << __FILE__ "(" << __LINE__ << "): "
+					<< "all_neighbors of cell " << cell.id
+					<< " doesn't equal neighbors_of + _to" << endl;
+				return EXIT_FAILURE;
+			}
+
 			// check offset
 			for (const auto& neighbor: cell.neighbors_of) {
 				const int ref_diff = (neighbor.id - cell.id) * grid.mapping.get_cell_length_in_indices(cell.id);