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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.optimize.manybody;
39  
40  import edu.rit.pj.IntegerForLoop;
41  import edu.rit.pj.IntegerSchedule;
42  import edu.rit.pj.ParallelRegion;
43  import edu.rit.pj.reduction.SharedDouble;
44  import ffx.potential.bonded.Residue;
45  
46  import java.util.Arrays;
47  
48  public class EnergyRegion extends ParallelRegion {
49  
50    private EnergyExpansion eE;
51    /** Flag to control use of 3-body terms. */
52    private boolean threeBodyTerm;
53  
54    private final SharedDouble self;
55    private final SharedDouble twoBody;
56    private final SharedDouble threeBody;
57    private final EnergyLoop[] energyLoops;
58    private Residue[] residues;
59    private int[] rotamers;
60    private int nResidues;
61  
62    public EnergyRegion(int nThreads) {
63      self = new SharedDouble();
64      twoBody = new SharedDouble();
65      threeBody = new SharedDouble();
66      energyLoops = new EnergyLoop[nThreads];
67    }
68  
69    public double getSelf() {
70      return self.get();
71    }
72  
73    public double getThreeBody() {
74      return threeBody.get();
75    }
76  
77    public double getTwoBody() {
78      return twoBody.get();
79    }
80  
81    public void init(EnergyExpansion eE, Residue[] residues, int[] rotamers, boolean threeBodyTerm) {
82      this.eE = eE;
83      this.rotamers = rotamers;
84      this.nResidues = residues.length;
85      this.residues = Arrays.copyOf(residues, nResidues);
86      this.threeBodyTerm = threeBodyTerm;
87    }
88  
89    @Override
90    public void run() throws Exception {
91      int threadID = getThreadIndex();
92      if (energyLoops[threadID] == null) {
93        energyLoops[threadID] = new EnergyLoop();
94      }
95      execute(0, nResidues - 1, energyLoops[threadID]);
96    }
97  
98    public void start() {
99      self.set(0.0);
100     twoBody.set(0.0);
101     threeBody.set(0.0);
102   }
103 
104   private class EnergyLoop extends IntegerForLoop {
105 
106     private double selfSum;
107     private double pairSum;
108     private double threeBodySum;
109 
110     @Override
111     public void finish() {
112       self.addAndGet(selfSum);
113       twoBody.addAndGet(pairSum);
114       threeBody.addAndGet(threeBodySum);
115     }
116 
117     @Override
118     public void run(int lb, int ub) {
119       for (int a = lb; a <= ub; a++) {
120         int ai = rotamers[a];
121         selfSum += eE.getSelf(a, ai);
122         for (int b = a + 1; b < nResidues; b++) {
123           int bi = rotamers[b];
124           pairSum += eE.get2Body(a, ai, b, bi);
125           if (threeBodyTerm) {
126             for (int c = b + 1; c < nResidues; c++) {
127               int ci = rotamers[c];
128               threeBodySum += eE.get3Body(residues, a, ai, b, bi, c, ci);
129             }
130           }
131         }
132       }
133     }
134 
135     @Override
136     public IntegerSchedule schedule() {
137       return IntegerSchedule.dynamic();
138     }
139 
140     @Override
141     public void start() {
142       selfSum = 0.0;
143       pairSum = 0.0;
144       threeBodySum = 0.0;
145     }
146   }
147 }