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.openmm;
39
40 import com.sun.jna.ptr.PointerByReference;
41
42 import static edu.uiowa.jopenmm.OpenMMLibrary.OpenMM_MinimizationReporter_create;
43 import static edu.uiowa.jopenmm.OpenMMLibrary.OpenMM_MinimizationReporter_destroy;
44
45 /**
46 * A MinimizationReporter can be passed to LocalEnergyMinimizer::minimize() to provide
47 * periodic information on the progress of minimization, and to give you the chance to
48 * stop minimization early. Define a subclass that overrides report() and implement it
49 * to take whatever action you want.
50 * <p>
51 * To correctly interpret the information passed to the reporter, you need to know a bit
52 * about how the minimizer works. The L-BFGS algorithm used by the minimizer does not
53 * support constraints. The minimizer therefore replaces all constraints with harmonic
54 * restraints, then performs unconstrained minimization of a combined objective function
55 * that is the sum of the system's potential energy and the restraint energy. Once
56 * minimization completes, it checks whether all constraints are satisfied to an acceptable
57 * tolerance. It not, it increases the strength of the harmonic restraints and performs
58 * additional minimization. If the error in constrained distances is especially large,
59 * it may choose to throw out all work that has been done so far and start over with
60 * stronger restraints. This has several important consequences.
61 *
62 * <ul>
63 * <li>The objective function being minimized not actually the same as the potential energy.</li>
64 * <li>The objective function and the potential energy can both increase between iterations.</li>
65 * <li>The total number of iterations performed could be larger than the number specified
66 * by the maxIterations argument, if that many iterations leaves unacceptable constraint errors.</li>
67 * <li>All work is provisional. It is possible for the minimizer to throw it out and start over.</li>
68 * </ul>
69 */
70 public class MinimizationReporter {
71
72 /**
73 * Reporter pointer.
74 */
75 private PointerByReference pointer;
76
77 /**
78 * Constructor.
79 */
80 public MinimizationReporter() {
81 pointer = OpenMM_MinimizationReporter_create();
82 }
83
84 /**
85 * Pointer to the reporter.
86 *
87 * @return the pointer.
88 */
89 public PointerByReference getPointer() {
90 return pointer;
91 }
92
93 /**
94 * Destroy the reporter.
95 */
96 public void destroy() {
97 if (pointer != null) {
98 OpenMM_MinimizationReporter_destroy(pointer);
99 pointer = null;
100 }
101 }
102
103 }