1 /* Ergo, version 3.8, a program for linear scaling electronic structure
2  * calculations.
3  * Copyright (C) 2019 Elias Rudberg, Emanuel H. Rubensson, Pawel Salek,
4  * and Anastasia Kruchinina.
5  *
6  * This program is free software: you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation, either version 3 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
18  *
19  * Primary academic reference:
20  * Ergo: An open-source program for linear-scaling electronic structure
21  * calculations,
22  * Elias Rudberg, Emanuel H. Rubensson, Pawel Salek, and Anastasia
23  * Kruchinina,
24  * SoftwareX 7, 107 (2018),
25  * <http://dx.doi.org/10.1016/j.softx.2018.03.005>
26  *
27  * For further information about Ergo, see <http://www.ergoscf.org>.
28  */
29 
30 /** @file box_system.h
31 
32     @brief BoxSystem class representing a hierarchical data structure
33     of boxes in 3D space (an oct-tree).
34 
35     @author: Elias Rudberg <em>responsible</em>
36 */
37 
38 #ifndef BOX_SYSTEM_HEADER
39 #define BOX_SYSTEM_HEADER
40 
41 
42 #include "realtype.h"
43 
44 
45 typedef struct
46 {
47   ergo_real centerCoords[3];
48   int originalIndex;
49 } box_item_struct;
50 
51 
52 typedef struct
53 {
54   ergo_real centerCoords[3];
55   ergo_real width;
56   int noOfItems;
57   int firstItemIndex;
58   int noOfChildBoxes;
59   int firstChildBoxIndex;
60 } box_struct_basic;
61 
62 typedef struct
63 {
64   int noOfBoxes;
65   int startIndexInBoxList;
66 } box_level_struct;
67 
68 #define MAX_NO_OF_BOX_LEVELS 30
69 
70 class BoxSystem
71 {
72  public:
73   int totNoOfBoxes;
74   int noOfLevels;
75   box_level_struct levelList[MAX_NO_OF_BOX_LEVELS];
76   box_struct_basic* boxList;
77   BoxSystem();
78   ~BoxSystem();
79   int create_box_system(box_item_struct* itemList,
80 			int noOfItems,
81 			ergo_real toplevelBoxSize);
82   int get_items_near_point(const box_item_struct* itemList,
83 			   const ergo_real* coords,
84 			   ergo_real distance,
85 			   int* resultOrgIndexList) const;
86  private:
87   int get_items_near_point_recursive(const box_item_struct* itemList,
88 				     const ergo_real* coords,
89 				     ergo_real distance,
90 				     int* resultOrgIndexList,
91 				     int level,
92 				     int boxIndex) const;
93 };
94 
95 ergo_real
96 get_min_distance_from_point_to_box(const ergo_real* boxCenterCoords,
97 				   ergo_real halfwidth,
98 				   const ergo_real* point);
99 
100 
101 
102 #endif
103