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.algorithms.mc;
39
40 import java.util.List;
41
42 /**
43 * The MetropolisMC interface defines the basic methods of a Metropolis Monte Carlo application.
44 * Intended to be a framework to allow you to take and revert a single step, and return basic
45 * information about the last step taken. Many of the methods will only return a meaningful result
46 * after the first step.
47 *
48 * @author Michael J. Schnieders
49 * @author Jacob M. Litman
50 * @since 1.0
51 */
52 public interface MetropolisMC {
53
54 /**
55 * Returns true if the move from e1 to e2 is accepted. For molecular systems, this will mean accept
56 * if e2 is less than e1, or accept with probability of exp(-dU/kbT) if e2 is greater than e1.
57 *
58 * @param e1 Initial energy
59 * @param e2 Trial energy
60 * @return If move accepted
61 */
62 boolean evaluateMove(double e1, double e2);
63
64 /**
65 * If last step taken was a success.
66 *
67 * @return Acceptance of last move
68 */
69 boolean getAccept();
70
71 /**
72 * Return starting energy from last attempted step.
73 *
74 * @return e1
75 */
76 double getE1();
77
78 /**
79 * Return trial energy from last attempted step.
80 *
81 * @return e2
82 */
83 double getE2();
84
85 /**
86 * Returns temperature of the Monte Carlo criterion.
87 *
88 * @return temperature
89 */
90 double getTemperature();
91
92 /**
93 * Sets temperature of Monte Carlo criterion.
94 *
95 * @param temp a double.
96 */
97 void setTemperature(double temp);
98
99 /**
100 * Returns the energy as of the last step taken (not including any extra potential energy
101 * adjustments).
102 *
103 * @return Last step's energy
104 */
105 double lastEnergy();
106
107 /**
108 * Calculates the current system energy and performs an MCMove.
109 *
110 * @param move MCMove to perform
111 * @return If move accepted
112 */
113 boolean mcStep(MCMove move);
114
115 /**
116 * Performs an MCMove.
117 *
118 * @param move MCMove to perform
119 * @param en1 Initial energy
120 * @return If move accepted
121 */
122 boolean mcStep(MCMove move, double en1);
123
124 /**
125 * Calculates the current system energy and performs a series of moves sequentially as a single
126 * hybrid step.
127 *
128 * @param moves MCMoves to perform
129 * @return If move/moves accepted
130 */
131 boolean mcStep(List<MCMove> moves);
132
133 /**
134 * Performs a series of moves sequentially, as a single hybrid step. Should also work with
135 * single-member lists.
136 *
137 * @param moves MCMoves to perform
138 * @param en1 Initial energy
139 * @return If move/moves accepted.
140 */
141 boolean mcStep(List<MCMove> moves, double en1);
142
143 /** If possible, reverts the last successful Monte Carlo step taken. */
144 void revertStep();
145
146 /**
147 * Sets whether the implementation prints its own messages.
148 *
149 * @param print Print energies, accept/reject, etc.
150 */
151 void setPrint(boolean print);
152 }