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 import edu.uiowa.jopenmm.OpenMM_Vec3;
42
43 import static edu.uiowa.jopenmm.OpenMMLibrary.OpenMM_State_destroy;
44 import static edu.uiowa.jopenmm.OpenMMLibrary.OpenMM_State_getDataTypes;
45 import static edu.uiowa.jopenmm.OpenMMLibrary.OpenMM_State_getEnergyParameterDerivatives;
46 import static edu.uiowa.jopenmm.OpenMMLibrary.OpenMM_State_getForces;
47 import static edu.uiowa.jopenmm.OpenMMLibrary.OpenMM_State_getKineticEnergy;
48 import static edu.uiowa.jopenmm.OpenMMLibrary.OpenMM_State_getParameters;
49 import static edu.uiowa.jopenmm.OpenMMLibrary.OpenMM_State_getPeriodicBoxVectors;
50 import static edu.uiowa.jopenmm.OpenMMLibrary.OpenMM_State_getPeriodicBoxVolume;
51 import static edu.uiowa.jopenmm.OpenMMLibrary.OpenMM_State_getPositions;
52 import static edu.uiowa.jopenmm.OpenMMLibrary.OpenMM_State_getPotentialEnergy;
53 import static edu.uiowa.jopenmm.OpenMMLibrary.OpenMM_State_getStepCount;
54 import static edu.uiowa.jopenmm.OpenMMLibrary.OpenMM_State_getTime;
55 import static edu.uiowa.jopenmm.OpenMMLibrary.OpenMM_State_getVelocities;
56
57 /**
58 * A State object records a snapshot of the current state of a simulation at a point in time.
59 * You create it by calling getState() on a Context.
60 * <p>
61 * When a State is created, you specify what information should be stored in it. This saves
62 * time and memory by only copying in the information that you actually want. This is especially
63 * important for forces and energies, since they may need to be calculated. If you query a
64 * State object for a piece of information which is not available (because it was not requested
65 * when the State was created), it will throw an exception.
66 */
67 public class State {
68
69 /**
70 * State pointer.
71 */
72 PointerByReference pointer;
73
74 /**
75 * Constructor.
76 *
77 * @param pointer Pointer to the state returned by a Context.
78 */
79 public State(PointerByReference pointer) {
80 this.pointer = pointer;
81 }
82
83 /**
84 * Destroy the state.
85 */
86 public void destroy() {
87 if (pointer != null) {
88 OpenMM_State_destroy(pointer);
89 pointer = null;
90 }
91 }
92
93 /**
94 * Get the data types.
95 *
96 * @return The data types.
97 */
98 public int getDataTypes() {
99 return OpenMM_State_getDataTypes(pointer);
100 }
101
102 /**
103 * Get the energy parameter derivatives.
104 *
105 * @return The energy parameter derivatives.
106 */
107 public PointerByReference getEnergyParameterDerivatives() {
108 return OpenMM_State_getEnergyParameterDerivatives(pointer);
109 }
110
111 /**
112 * Get the forces.
113 *
114 * @return The forces.
115 */
116 public double[] getForces() {
117 Vec3Array forces = new Vec3Array(OpenMM_State_getForces(pointer));
118 return forces.getArray();
119 }
120
121 /**
122 * Get the kinetic energy.
123 *
124 * @return The kinetic energy.
125 */
126 public double getKineticEnergy() {
127 return OpenMM_State_getKineticEnergy(pointer);
128 }
129
130 /**
131 * Get the parameters.
132 *
133 * @return The parameters.
134 */
135 public PointerByReference getParameters() {
136 return OpenMM_State_getParameters(pointer);
137 }
138
139 /**
140 * Get the periodic box vectors.
141 *
142 * @return The periodic box vectors.
143 */
144 public double[][] getPeriodicBoxVectors() {
145 OpenMM_Vec3 a = new OpenMM_Vec3();
146 OpenMM_Vec3 b = new OpenMM_Vec3();
147 OpenMM_Vec3 c = new OpenMM_Vec3();
148 OpenMM_State_getPeriodicBoxVectors(pointer, a, b, c);
149 double[][] latticeVectors = new double[3][3];
150 latticeVectors[0][0] = a.x;
151 latticeVectors[0][1] = a.y;
152 latticeVectors[0][2] = a.z;
153 latticeVectors[1][0] = b.x;
154 latticeVectors[1][1] = b.y;
155 latticeVectors[1][2] = b.z;
156 latticeVectors[2][0] = c.x;
157 latticeVectors[2][1] = c.y;
158 latticeVectors[2][2] = c.z;
159 return latticeVectors;
160 }
161
162 /**
163 * Get the periodic box volume.
164 *
165 * @return The periodic box volume.
166 */
167 public double getPeriodicBoxVolume() {
168 return OpenMM_State_getPeriodicBoxVolume(pointer);
169 }
170
171 /**
172 * Get the pointer to the state.
173 *
174 * @return The pointer to the state.
175 */
176 public PointerByReference getPointer() {
177 return pointer;
178 }
179
180 /**
181 * Get the positions.
182 *
183 * @return The positions.
184 */
185 public double[] getPositions() {
186 Vec3Array positions = new Vec3Array(OpenMM_State_getPositions(pointer));
187 return positions.getArray();
188 }
189
190 /**
191 * Get the potential energy.
192 *
193 * @return The potential energy.
194 */
195 public double getPotentialEnergy() {
196 return OpenMM_State_getPotentialEnergy(pointer);
197 }
198
199 /**
200 * Get the step count.
201 *
202 * @return The step count.
203 */
204 public long getStepCount() {
205 return OpenMM_State_getStepCount(pointer);
206 }
207
208 /**
209 * Get the time.
210 *
211 * @return The time.
212 */
213 public double getTime() {
214 return OpenMM_State_getTime(pointer);
215 }
216
217 /**
218 * Get the velocities.
219 *
220 * @return The velocities.
221 */
222 public double[] getVelocities() {
223 Vec3Array velocities = new Vec3Array(OpenMM_State_getVelocities(pointer));
224 return velocities.getArray();
225 }
226
227 }