Add copy of (proposed) grid structure.

grid.h

@@ -0,0 +1,45 @@
+#ifndef GRID_H_INCLUDED
+#define GRID_H_INCLUDED
+
+/*   GRID_TOPOLOGY and GRID_GEOMETRY must be at the beginning of every
+ *   grid type.  
+ *
+ *
+ */
+#define GRID_TOPOLOGY                           \
+   int    dimensions;                           \
+                                                \
+   int    number_of_cells;                      \
+   int    number_of_faces;                      \
+   int    number_of_nodes;                      \
+                                                \
+   int    *face_nodes;                          \
+   int    *face_nodepos;                        \
+   int    *face_cells;                          \
+                                                \
+   int    *cell_faces;                          \
+   int    *cell_facepos;                        \
+   
+#define GRID_GEOMETRY                           \
+   double *node_coordinates;                    \
+                                                \
+   double *face_centroids;                      \
+   double *face_areas;                          \
+   double *face_normals;                        \
+                                                \
+   double *cell_centroids;                      \
+   double *cell_volumes;                        \
+   
+   
+typedef struct {
+   GRID_TOPOLOGY
+   GRID_GEOMETRY
+} grid_t;
+
+
+void free_grid           (grid_t *g);
+void alloc_grid_geometry (grid_t *g);
+void print_grid_summary  (grid_t *g);
+
+
+#endif