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root/group/trunk/OOPSE-4/src/primitives/Bend.cpp
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Comparing trunk/OOPSE-4/src/primitives/Bend.cpp (file contents):
Revision 1492 by tim, Fri Sep 24 16:27:58 2004 UTC vs.
Revision 1930 by gezelter, Wed Jan 12 22:41:40 2005 UTC

# Line 1 | Line 1
1 < #include "primitives/SRI.hpp"
2 < #include "primitives/Atom.hpp"
3 <
4 < #include <math.h>
5 < #include <iostream>
6 < #include <stdlib.h>
7 <
8 < void Bend::set_atoms( Atom &a, Atom &b, Atom &c){
9 <
10 <  c_p_a = &a;
11 <  c_p_b = &b;
12 <  c_p_c = &c;
13 <
14 <  c_potential_E = 0.0;
15 < }
16 <
17 <
18 < void Bend::calc_forces(){
19 <  
20 <  double dx,dy,dz,gx,gy,gz,dx2,dy2,dz2,gx2,gy2,gz2;
21 <  double rij2, rkj2, riji2, rkji2, dot, denom, cosang, angl;
22 <  
23 <  double sina2, sinai;
24 <
25 <  double comf2, comf3, comf4;
26 <  double dcsidx, dcsidy, dcsidz, dcskdx, dcskdy, dcskdz;
27 <  // double dcsjdx, dcsjdy, dcsjdz;
28 <  double dadxi, dadyi, dadzi;
29 <  double dadxk, dadyk, dadzk;//, dadxj, dadyj, dadzj;
30 <  double daxi, dayi, dazi, daxk, dayk, dazk, daxj, dayj, dazj;
31 <  
32 <  double aR[3], bR[3], cR[3];
33 <  double aF[3], bF[3], cF[3];
34 <
35 <  c_p_a->getPos( aR );
36 <  c_p_b->getPos( bR );
37 <  c_p_c->getPos( cR );
38 <  
39 <
40 <  dx = aR[0] - bR[0];
41 <  dy = aR[1] - bR[1];
42 <  dz = aR[2] - bR[2];
1 > /*
2 > * Copyright (c) 2005 The University of Notre Dame. All Rights Reserved.
3 > *
4 > * The University of Notre Dame grants you ("Licensee") a
5 > * non-exclusive, royalty free, license to use, modify and
6 > * redistribute this software in source and binary code form, provided
7 > * that the following conditions are met:
8 > *
9 > * 1. Acknowledgement of the program authors must be made in any
10 > *    publication of scientific results based in part on use of the
11 > *    program.  An acceptable form of acknowledgement is citation of
12 > *    the article in which the program was described (Matthew
13 > *    A. Meineke, Charles F. Vardeman II, Teng Lin, Christopher
14 > *    J. Fennell and J. Daniel Gezelter, "OOPSE: An Object-Oriented
15 > *    Parallel Simulation Engine for Molecular Dynamics,"
16 > *    J. Comput. Chem. 26, pp. 252-271 (2005))
17 > *
18 > * 2. Redistributions of source code must retain the above copyright
19 > *    notice, this list of conditions and the following disclaimer.
20 > *
21 > * 3. Redistributions in binary form must reproduce the above copyright
22 > *    notice, this list of conditions and the following disclaimer in the
23 > *    documentation and/or other materials provided with the
24 > *    distribution.
25 > *
26 > * This software is provided "AS IS," without a warranty of any
27 > * kind. All express or implied conditions, representations and
28 > * warranties, including any implied warranty of merchantability,
29 > * fitness for a particular purpose or non-infringement, are hereby
30 > * excluded.  The University of Notre Dame and its licensors shall not
31 > * be liable for any damages suffered by licensee as a result of
32 > * using, modifying or distributing the software or its
33 > * derivatives. In no event will the University of Notre Dame or its
34 > * licensors be liable for any lost revenue, profit or data, or for
35 > * direct, indirect, special, consequential, incidental or punitive
36 > * damages, however caused and regardless of the theory of liability,
37 > * arising out of the use of or inability to use software, even if the
38 > * University of Notre Dame has been advised of the possibility of
39 > * such damages.
40 > */
41  
42 <  gx = cR[0] - bR[0];
45 <  gy = cR[1] - bR[1];
46 <  gz = cR[2] - bR[2];
47 <  
48 <  dx2 = dx * dx;
49 <  dy2 = dy * dy;
50 <  dz2 = dz * dz;
42 > #include "primitives/Bend.hpp"
43  
44 <  gx2 = gx * gx;
53 <  gy2 = gy * gy;
54 <  gz2 = gz * gz;
55 <  
56 <  rij2 = dx2 + dy2 + dz2;
57 <  rkj2 = gx2 + gy2 + gz2;
58 <  
59 <  riji2 = 1.0 / rij2;
60 <  rkji2 = 1.0 / rkj2;
44 > namespace oopse {
45  
46 <  dot = dx * gx + dy * gy + dz * gz;
47 <  denom = sqrt((riji2 * rkji2));
48 <  cosang = dot * denom;
46 > /**@todo still a lot left to improve*/
47 > void Bend::calcForce() {
48 >    Vector3d pos1 = atom1_->getPos();
49 >    Vector3d pos2 = atom2_->getPos();
50 >    Vector3d pos3 = atom3_->getPos();
51  
52 <  if(cosang > 1.0)cosang = 1.0;
53 <  if(cosang < -1.0) cosang = -1.0;
52 >    Vector3d r21 = pos1 - pos2;
53 >    double d21 = r21.length();
54  
55 <  angl = acos(cosang);
70 <  angl = angl * 180.0 / M_PI;
55 >    double d21inv = 1.0 / d21;
56  
57 <  sina2 = 1.0 - cosang*cosang;
58 <  if(fabs(sina2) < 1.0E-12 ) sina2 = 1.0E-12;
74 <  sinai = 1.0 / sqrt(sina2);
57 >    Vector3d r23 = pos3 - pos2;
58 >    double d23 = r23.length();
59  
60 <  comf2 = cosang * riji2;
77 <  comf3 = cosang * rkji2;
78 <  comf4 = bend_force(angl);
60 >    double d23inv = 1.0 / d23;
61  
62 +    double cosTheta = dot(r21, r23) / (d21 * d23);
63  
64 <  dcsidx = gx*denom - comf2*dx;
65 <  dcsidy = gy*denom - comf2*dy;
66 <  dcsidz = gz*denom - comf2*dz;
67 <  
68 <  dcskdx = dx*denom - comf3*gx;
69 <  dcskdy = dy*denom - comf3*gy;
87 <  dcskdz = dz*denom - comf3*gz;
88 <  
89 < //   dcsjdx = -dcsidx - dcskdx;
90 < //   dcsjdy = -dcsidy - dcskdy;
91 < //   dcsjdz = -dcsidz - dcskdz;
64 >    //check roundoff    
65 >    if (cosTheta > 1.0) {
66 >        cosTheta = 1.0;
67 >    } else if (cosTheta < -1.0) {
68 >        cosTheta = -1.0;
69 >    }
70  
71 <  dadxi = -sinai*dcsidx;
94 <  dadyi = -sinai*dcsidy;
95 <  dadzi = -sinai*dcsidz;
71 >    double theta = acos(cosTheta);
72  
73 <  dadxk = -sinai*dcskdx;
98 <  dadyk = -sinai*dcskdy;
99 <  dadzk = -sinai*dcskdz;
73 >    double dVdTheta;
74  
75 < //   dadxj = -dadxi - dadxk;
102 < //   dadyj = -dadyi - dadyk;
103 < //   dadzj = -dadzi - dadzk;
75 >    bendType_->calcForce(theta, potential_, dVdTheta);
76  
77 <  daxi = comf4*dadxi;
106 <  dayi = comf4*dadyi;
107 <  dazi = comf4*dadzi;
77 >    double sinTheta = sqrt(1.0 - cosTheta * cosTheta);
78  
79 <  daxk = comf4*dadxk;
80 <  dayk = comf4*dadyk;
81 <  dazk = comf4*dadzk;
112 <  
113 <  daxj = -daxi - daxk;
114 <  dayj = -dayi - dayk;
115 <  dazj = -dazi - dazk;
116 <  
117 <  aF[0] = daxi;
118 <  aF[1] = dayi;
119 <  aF[2] = dazi;
79 >    if (fabs(sinTheta) < 1.0E-6) {
80 >        sinTheta = 1.0E-6;
81 >    }
82  
83 <  bF[0] = daxj;
84 <  bF[1] = dayj;
123 <  bF[2] = dazj;
83 >    double commonFactor1 = dVdTheta / sinTheta * d21inv;
84 >    double commonFactor2 = dVdTheta / sinTheta * d23inv;
85  
86 <  cF[0] = daxk;
87 <  cF[1] = dayk;
127 <  cF[2] = dazk;
86 >    Vector3d force1 = commonFactor1 * (r23 * d23inv - r21*d21inv*cosTheta);
87 >    Vector3d force3 = commonFactor2 * (r21 * d21inv - r23*d23inv*cosTheta);
88  
89 <  c_p_a->addFrc(aF);
90 <  c_p_b->addFrc(bF);
91 <  c_p_c->addFrc(cF);
89 >    //total force in current bend is zero
90 >    Vector3d force2 = force1 + force3;
91 >    force2 *= -1.0;
92  
93 <  return;
93 >    atom1_->addFrc(force1);
94 >    atom2_->addFrc(force2);
95 >    atom3_->addFrc(force3);
96   }
97 +
98 + } //end namespace oopse

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