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Comparing trunk/OOPSE-2.0/src/primitives/Torsion.cpp (file contents):
Revision 1492 by tim, Fri Sep 24 16:27:58 2004 UTC vs.
Revision 2448 by tim, Wed Nov 16 23:10:02 2005 UTC

# Line 1 | Line 1
1 < #include "primitives/SRI.hpp"
2 < #include "primitives/Atom.hpp"
3 < #include <math.h>
4 < #include <iostream>
5 < #include <stdlib.h>
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 > #include "primitives/Torsion.hpp"
43  
44 < void Torsion::set_atoms( Atom &a, Atom &b, Atom &c, Atom &d){
8 <  c_p_a = &a;
9 <  c_p_b = &b;
10 <  c_p_c = &c;
11 <  c_p_d = &d;
12 < }
44 > namespace oopse {
45  
46 +  Torsion::Torsion(Atom *atom1, Atom *atom2, Atom *atom3, Atom *atom4,
47 +                   TorsionType *tt) :
48 +    atom1_(atom1), atom2_(atom2), atom3_(atom3), atom4_(atom4), torsionType_(tt) { }
49  
50 < void Torsion::calc_forces(){
16 <  
17 <  /**********************************************************************
18 <   *
19 <   * initialize vectors
20 <   *
21 <   ***********************************************************************/
22 <  
23 <  vect r_ab; /* the vector whose origin is a and end is b */
24 <  vect r_cb; /* the vector whose origin is c and end is b */
25 <  vect r_cd; /* the vector whose origin is c and end is b */
26 <  vect r_cr1; /* the cross product of r_ab and r_cb */
27 <  vect r_cr2; /* the cross product of r_cb and r_cd */
50 >  void Torsion::calcForce(double& angle) {
51  
52 <  double r_cr1_x2; /* the components of r_cr1 squared */
53 <  double r_cr1_y2;
54 <  double r_cr1_z2;
55 <  
33 <  double r_cr2_x2; /* the components of r_cr2 squared */
34 <  double r_cr2_y2;
35 <  double r_cr2_z2;
52 >    Vector3d pos1 = atom1_->getPos();
53 >    Vector3d pos2 = atom2_->getPos();
54 >    Vector3d pos3 = atom3_->getPos();
55 >    Vector3d pos4 = atom4_->getPos();
56  
57 <  double r_cr1_sqr; /* the length of r_cr1 squared */
58 <  double r_cr2_sqr; /* the length of r_cr2 squared */
59 <  
40 <  double r_cr1_r_cr2; /* the length of r_cr1 * length of r_cr2 */
41 <  
42 <  double aR[3], bR[3], cR[3], dR[3];
43 <  double aF[3], bF[3], cF[3], dF[3];
57 >    Vector3d r21 = pos1 - pos2;
58 >    Vector3d r32 = pos2 - pos3;
59 >    Vector3d r43 = pos3 - pos4;
60  
61 <  c_p_a->getPos( aR );
62 <  c_p_b->getPos( bR );
63 <  c_p_c->getPos( cR );
64 <  c_p_d->getPos( dR );
61 >    //  Calculate the cross products and distances
62 >    Vector3d A = cross(r21, r32);
63 >    double rA = A.length();
64 >    Vector3d B = cross(r32, r43);
65 >    double rB = B.length();
66 >    Vector3d C = cross(r32, A);
67 >    double rC = C.length();
68  
69 <  r_ab.x = bR[0] - aR[0];
70 <  r_ab.y = bR[1] - aR[1];
71 <  r_ab.z = bR[2] - aR[2];
72 <  r_ab.length  = sqrt((r_ab.x * r_ab.x + r_ab.y * r_ab.y + r_ab.z * r_ab.z));
69 >    A.normalize();
70 >    B.normalize();
71 >    C.normalize();
72 >    
73 >    //  Calculate the sin and cos
74 >    double cos_phi = dot(A, B) ;
75 >    if (cos_phi > 1.0) cos_phi = 1.0;
76 >    if (cos_phi < -1.0) cos_phi = -1.0;
77  
78 <  r_cb.x = bR[0] - cR[0];
79 <  r_cb.y = bR[1] - cR[1];
80 <  r_cb.z = bR[2] - cR[2];
81 <  r_cb.length = sqrt((r_cb.x * r_cb.x + r_cb.y * r_cb.y + r_cb.z * r_cb.z));
78 >    double dVdcosPhi;
79 >    torsionType_->calcForce(cos_phi, potential_, dVdcosPhi);
80 >    Vector3d f1;
81 >    Vector3d f2;
82 >    Vector3d f3;
83  
84 <  r_cd.x = dR[0] - cR[0];
85 <  r_cd.y = dR[1] - cR[1];
62 <  r_cd.z = dR[2] - cR[2];
63 <  r_cd.length = sqrt((r_cd.x * r_cd.x + r_cd.y * r_cd.y + r_cd.z * r_cd.z));
84 >    Vector3d dcosdA = (cos_phi * A - B) /rA;
85 >    Vector3d dcosdB = (cos_phi * B - A) /rB;
86  
87 <  r_cr1.x = r_ab.y * r_cb.z - r_cb.y * r_ab.z;
88 <  r_cr1.y = r_ab.z * r_cb.x - r_cb.z * r_ab.x;
89 <  r_cr1.z = r_ab.x * r_cb.y - r_cb.x * r_ab.y;
90 <  r_cr1_x2 = r_cr1.x * r_cr1.x;
91 <  r_cr1_y2 = r_cr1.y * r_cr1.y;
92 <  r_cr1_z2 = r_cr1.z * r_cr1.z;
93 <  r_cr1_sqr = r_cr1_x2 + r_cr1_y2 + r_cr1_z2;
94 <  r_cr1.length = sqrt(r_cr1_sqr);
87 >    f1 = dVdcosPhi * cross(r32, dcosdA);
88 >    f2 = dVdcosPhi * ( cross(r43, dcosdB) - cross(r21, dcosdA));
89 >    f3 = dVdcosPhi * cross(dcosdB, r32);
90 >    
91 >    atom1_->addFrc(f1);
92 >    atom2_->addFrc(f2 - f1);
93 >    atom3_->addFrc(f3 - f2);
94 >    atom4_->addFrc(-f3);
95 >    angle = acos(cos_phi) /M_PI * 180.0;
96 >  }
97  
74  r_cr2.x = r_cb.y * r_cd.z - r_cd.y * r_cb.z;
75  r_cr2.y = r_cb.z * r_cd.x - r_cd.z * r_cb.x;
76  r_cr2.z = r_cb.x * r_cd.y - r_cd.x * r_cb.y;
77  r_cr2_x2 = r_cr2.x * r_cr2.x;
78  r_cr2_y2 = r_cr2.y * r_cr2.y;
79  r_cr2_z2 = r_cr2.z * r_cr2.z;
80  r_cr2_sqr = r_cr2_x2 + r_cr2_y2 + r_cr2_z2;
81  r_cr2.length = sqrt(r_cr2_sqr);
82
83  r_cr1_r_cr2 = r_cr1.length * r_cr2.length;
84
85  /**********************************************************************
86   *
87   * dot product and angle calculations
88   *
89   ***********************************************************************/
90  
91  double cr1_dot_cr2; /* the dot product of the cr1 and cr2 vectors */
92  double cos_phi; /* the cosine of the torsion angle */
93
94  cr1_dot_cr2 = r_cr1.x * r_cr2.x + r_cr1.y * r_cr2.y + r_cr1.z * r_cr2.z;
95  
96  cos_phi = cr1_dot_cr2 / r_cr1_r_cr2;
97  
98   /* adjust for the granularity of the numbers for angles near 0 or pi */
99
100  if(cos_phi > 1.0) cos_phi = 1.0;
101  if(cos_phi < -1.0) cos_phi = -1.0;
102
103
104  /********************************************************************
105   *
106   * This next section calculates derivatives needed for the force
107   * calculation
108   *
109   ********************************************************************/
110
111
112  /* the derivatives of cos phi with respect to the x, y,
113     and z components of vectors cr1 and cr2. */
114  double d_cos_dx_cr1;
115  double d_cos_dy_cr1;
116  double d_cos_dz_cr1;
117  double d_cos_dx_cr2;
118  double d_cos_dy_cr2;
119  double d_cos_dz_cr2;
120
121  d_cos_dx_cr1 = r_cr2.x / r_cr1_r_cr2 - (cos_phi * r_cr1.x) / r_cr1_sqr;
122  d_cos_dy_cr1 = r_cr2.y / r_cr1_r_cr2 - (cos_phi * r_cr1.y) / r_cr1_sqr;
123  d_cos_dz_cr1 = r_cr2.z / r_cr1_r_cr2 - (cos_phi * r_cr1.z) / r_cr1_sqr;
124
125  d_cos_dx_cr2 = r_cr1.x / r_cr1_r_cr2 - (cos_phi * r_cr2.x) / r_cr2_sqr;
126  d_cos_dy_cr2 = r_cr1.y / r_cr1_r_cr2 - (cos_phi * r_cr2.y) / r_cr2_sqr;
127  d_cos_dz_cr2 = r_cr1.z / r_cr1_r_cr2 - (cos_phi * r_cr2.z) / r_cr2_sqr;
128
129  /***********************************************************************
130   *
131   * Calculate the actual forces and place them in the atoms.
132   *
133   ***********************************************************************/
134
135  double force; /*the force scaling factor */
136
137  force = torsion_force(cos_phi);
138
139  aF[0] = force * (d_cos_dy_cr1 * r_cb.z - d_cos_dz_cr1 * r_cb.y);
140  aF[1] = force * (d_cos_dz_cr1 * r_cb.x - d_cos_dx_cr1 * r_cb.z);
141  aF[2] = force * (d_cos_dx_cr1 * r_cb.y - d_cos_dy_cr1 * r_cb.x);
142
143  bF[0] = force * (  d_cos_dy_cr1 * (r_ab.z - r_cb.z)
144                   - d_cos_dy_cr2 *  r_cd.z      
145                   + d_cos_dz_cr1 * (r_cb.y - r_ab.y)
146                   + d_cos_dz_cr2 *  r_cd.y);
147  bF[1] = force * (  d_cos_dx_cr1 * (r_cb.z - r_ab.z)
148                   + d_cos_dx_cr2 *  r_cd.z      
149                   + d_cos_dz_cr1 * (r_ab.x - r_cb.x)
150                   - d_cos_dz_cr2 *  r_cd.x);
151  bF[2] = force * (  d_cos_dx_cr1 * (r_ab.y - r_cb.y)
152                   - d_cos_dx_cr2 *  r_cd.y      
153                   + d_cos_dy_cr1 * (r_cb.x - r_ab.x)
154                   + d_cos_dy_cr2 *  r_cd.x);
155
156  cF[0] = force * (- d_cos_dy_cr1 *  r_ab.z
157                   - d_cos_dy_cr2 * (r_cb.z - r_cd.z)
158                   + d_cos_dz_cr1 *  r_ab.y
159                   - d_cos_dz_cr2 * (r_cd.y - r_cb.y));
160  cF[1] = force * (  d_cos_dx_cr1 *  r_ab.z
161                   - d_cos_dx_cr2 * (r_cd.z - r_cb.z)
162                   - d_cos_dz_cr1 *  r_ab.x
163                   - d_cos_dz_cr2 * (r_cb.x - r_cd.x));
164  cF[2] = force * (- d_cos_dx_cr1 *  r_ab.y
165                   - d_cos_dx_cr2 * (r_cb.y - r_cd.y)
166                   + d_cos_dy_cr1 *  r_ab.x
167                   - d_cos_dy_cr2 * (r_cd.x - r_cb.x));
168
169  dF[0] = force * (d_cos_dy_cr2 * r_cb.z - d_cos_dz_cr2 * r_cb.y);
170  dF[1] = force * (d_cos_dz_cr2 * r_cb.x - d_cos_dx_cr2 * r_cb.z);
171  dF[2] = force * (d_cos_dx_cr2 * r_cb.y - d_cos_dy_cr2 * r_cb.x);
172
173
174  c_p_a->addFrc(aF);
175  c_p_b->addFrc(bF);
176  c_p_c->addFrc(cF);
177  c_p_d->addFrc(dF);
98   }

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