1 // ******************************************************************************
2 //
3 // Title: Force Field X.
4 // Description: Force Field X - Software for Molecular Biophysics.
5 // Copyright: Copyright (c) Michael J. Schnieders 2001-2025.
6 //
7 // This file is part of Force Field X.
8 //
9 // Force Field X is free software; you can redistribute it and/or modify it
10 // under the terms of the GNU General Public License version 3 as published by
11 // the Free Software Foundation.
12 //
13 // Force Field X is distributed in the hope that it will be useful, but WITHOUT
14 // ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
15 // FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
16 // details.
17 //
18 // You should have received a copy of the GNU General Public License along with
19 // Force Field X; if not, write to the Free Software Foundation, Inc., 59 Temple
20 // Place, Suite 330, Boston, MA 02111-1307 USA
21 //
22 // Linking this library statically or dynamically with other modules is making a
23 // combined work based on this library. Thus, the terms and conditions of the
24 // GNU General Public License cover the whole combination.
25 //
26 // As a special exception, the copyright holders of this library give you
27 // permission to link this library with independent modules to produce an
28 // executable, regardless of the license terms of these independent modules, and
29 // to copy and distribute the resulting executable under terms of your choice,
30 // provided that you also meet, for each linked independent module, the terms
31 // and conditions of the license of that module. An independent module is a
32 // module which is not derived from or based on this library. If you modify this
33 // library, you may extend this exception to your version of the library, but
34 // you are not obligated to do so. If you do not wish to do so, delete this
35 // exception statement from your version.
36 //
37 // ******************************************************************************
38 package ffx.numerics.multipole;
39
40 /**
41 * Operators that are supported.
42 */
43 public enum Operator {
44 /**
45 * Coulomb operator.
46 */
47 COULOMB,
48 /**
49 * Screened Coulomb operator.
50 */
51 SCREENED_COULOMB,
52 /**
53 * Charge-Penetration nucleus-multipole operator.
54 */
55 AMOEBA_PLUS_DAMP_FIELD,
56 /**
57 * Mpole-Mpole Interaction for Amoeba+
58 */
59 AMOEBA_PLUS_OVERLAP_FIELD,
60 /**
61 * IndDipole-Mpole Interaction for Amoeba+
62 */
63 THOLE_DIRECT_FIELD,
64 /**
65 * Core-Mpole Interaction with 2 identical atoms
66 */
67 AMOEBA_PLUS_SYM_DAMP_FIELD,
68 /**
69 * Thole field operator.
70 */
71 THOLE_FIELD
72 }