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root/group/trunk/OOPSE/libmdtools/Thermo.cpp
Revision: 458
Committed: Fri Apr 4 19:47:19 2003 UTC (21 years, 3 months ago) by gezelter
File size: 6343 byte(s)
Log Message:
Changes for Extended System

File Contents

# Content
1 #include <cmath>
2 #include <iostream>
3 using namespace std;
4
5 #ifdef IS_MPI
6 #include <mpi.h>
7 #endif //is_mpi
8
9 #include "Thermo.hpp"
10 #include "SRI.hpp"
11 #include "Integrator.hpp"
12 #include "simError.h"
13
14 #ifdef IS_MPI
15 #define __C
16 #include "mpiSimulation.hpp"
17 #endif // is_mpi
18
19
20 #define BASE_SEED 123456789
21
22 Thermo::Thermo( SimInfo* the_entry_plug ) {
23 entry_plug = the_entry_plug;
24 int baseSeed = BASE_SEED;
25
26 gaussStream = new gaussianSPRNG( baseSeed );
27 }
28
29 Thermo::~Thermo(){
30 delete gaussStream;
31 }
32
33 double Thermo::getKinetic(){
34
35 const double e_convert = 4.184E-4; // convert kcal/mol -> (amu A^2)/fs^2
36 double vx2, vy2, vz2;
37 double kinetic, v_sqr;
38 int kl;
39 double jx2, jy2, jz2; // the square of the angular momentums
40
41 DirectionalAtom *dAtom;
42
43 int n_atoms;
44 double kinetic_global;
45 Atom** atoms;
46
47
48 n_atoms = entry_plug->n_atoms;
49 atoms = entry_plug->atoms;
50
51 kinetic = 0.0;
52 kinetic_global = 0.0;
53 for( kl=0; kl < n_atoms; kl++ ){
54
55 vx2 = atoms[kl]->get_vx() * atoms[kl]->get_vx();
56 vy2 = atoms[kl]->get_vy() * atoms[kl]->get_vy();
57 vz2 = atoms[kl]->get_vz() * atoms[kl]->get_vz();
58
59 v_sqr = vx2 + vy2 + vz2;
60 kinetic += atoms[kl]->getMass() * v_sqr;
61
62 if( atoms[kl]->isDirectional() ){
63
64 dAtom = (DirectionalAtom *)atoms[kl];
65
66 jx2 = dAtom->getJx() * dAtom->getJx();
67 jy2 = dAtom->getJy() * dAtom->getJy();
68 jz2 = dAtom->getJz() * dAtom->getJz();
69
70 kinetic += (jx2 / dAtom->getIxx()) + (jy2 / dAtom->getIyy())
71 + (jz2 / dAtom->getIzz());
72 }
73 }
74 #ifdef IS_MPI
75 MPI_Allreduce(&kinetic,&kinetic_global,1,MPI_DOUBLE,
76 MPI_SUM, MPI_COMM_WORLD);
77 kinetic = kinetic_global;
78 #endif //is_mpi
79
80 kinetic = kinetic * 0.5 / e_convert;
81
82 return kinetic;
83 }
84
85 double Thermo::getPotential(){
86
87 double potential_local;
88 double potential;
89 int el, nSRI;
90 Molecule* molecules;
91
92 molecules = entry_plug->molecules;
93 nSRI = entry_plug->n_SRI;
94
95 potential_local = 0.0;
96 potential = 0.0;
97 potential_local += entry_plug->lrPot;
98
99 for( el=0; el<entry_plug->n_mol; el++ ){
100 potential_local += molecules[el].getPotential();
101 }
102
103 // Get total potential for entire system from MPI.
104 #ifdef IS_MPI
105 MPI_Allreduce(&potential_local,&potential,1,MPI_DOUBLE,
106 MPI_SUM, MPI_COMM_WORLD);
107 #else
108 potential = potential_local;
109 #endif // is_mpi
110
111 #ifdef IS_MPI
112 /*
113 std::cerr << "node " << worldRank << ": after pot = " << potential << "\n";
114 */
115 #endif
116
117 return potential;
118 }
119
120 double Thermo::getTotalE(){
121
122 double total;
123
124 total = this->getKinetic() + this->getPotential();
125 return total;
126 }
127
128 double Thermo::getTemperature(){
129
130 const double kb = 1.9872179E-3; // boltzman's constant in kcal/(mol K)
131 double temperature;
132
133 temperature = ( 2.0 * this->getKinetic() ) / ((double)entry_plug->ndf * kb );
134 return temperature;
135 }
136
137 double Thermo::getPressure(){
138 // returns pressure in units amu*fs^-2*Ang^-1
139 // routine derived via viral theorem description in:
140 // Paci, E. and Marchi, M. J.Phys.Chem. 1996, 100, 4314-4322
141
142 return 0.0;
143 }
144
145 void Thermo::velocitize() {
146
147 double x,y;
148 double vx, vy, vz;
149 double jx, jy, jz;
150 int i, vr, vd; // velocity randomizer loop counters
151 double vdrift[3];
152 double vbar;
153 const double kb = 8.31451e-7; // kb in amu, angstroms, fs, etc.
154 double av2;
155 double kebar;
156 int n_atoms;
157 Atom** atoms;
158 DirectionalAtom* dAtom;
159 double temperature;
160 int n_oriented;
161 int n_constraints;
162
163 atoms = entry_plug->atoms;
164 n_atoms = entry_plug->n_atoms;
165 temperature = entry_plug->target_temp;
166 n_oriented = entry_plug->n_oriented;
167 n_constraints = entry_plug->n_constraints;
168
169 kebar = kb * temperature * (double)entry_plug->ndf /
170 ( 2.0 * (double)entry_plug->ndfRaw );
171
172 for(vr = 0; vr < n_atoms; vr++){
173
174 // uses equipartition theory to solve for vbar in angstrom/fs
175
176 av2 = 2.0 * kebar / atoms[vr]->getMass();
177 vbar = sqrt( av2 );
178
179 // vbar = sqrt( 8.31451e-7 * temperature / atoms[vr]->getMass() );
180
181 // picks random velocities from a gaussian distribution
182 // centered on vbar
183
184 vx = vbar * gaussStream->getGaussian();
185 vy = vbar * gaussStream->getGaussian();
186 vz = vbar * gaussStream->getGaussian();
187
188 atoms[vr]->set_vx( vx );
189 atoms[vr]->set_vy( vy );
190 atoms[vr]->set_vz( vz );
191 }
192
193 // Get the Center of Mass drift velocity.
194
195 getCOMVel(vdrift);
196
197 // Corrects for the center of mass drift.
198 // sums all the momentum and divides by total mass.
199
200 for(vd = 0; vd < n_atoms; vd++){
201
202 vx = atoms[vd]->get_vx();
203 vy = atoms[vd]->get_vy();
204 vz = atoms[vd]->get_vz();
205
206 vx -= vdrift[0];
207 vy -= vdrift[1];
208 vz -= vdrift[2];
209
210 atoms[vd]->set_vx(vx);
211 atoms[vd]->set_vy(vy);
212 atoms[vd]->set_vz(vz);
213 }
214 if( n_oriented ){
215
216 for( i=0; i<n_atoms; i++ ){
217
218 if( atoms[i]->isDirectional() ){
219
220 dAtom = (DirectionalAtom *)atoms[i];
221
222 vbar = sqrt( 2.0 * kebar * dAtom->getIxx() );
223 jx = vbar * gaussStream->getGaussian();
224
225 vbar = sqrt( 2.0 * kebar * dAtom->getIyy() );
226 jy = vbar * gaussStream->getGaussian();
227
228 vbar = sqrt( 2.0 * kebar * dAtom->getIzz() );
229 jz = vbar * gaussStream->getGaussian();
230
231 dAtom->setJx( jx );
232 dAtom->setJy( jy );
233 dAtom->setJz( jz );
234 }
235 }
236 }
237 }
238
239 void Thermo::getCOMVel(double vdrift[3]){
240
241 double mtot, mtot_local;
242 double vdrift_local[3];
243 int vd, n_atoms;
244 Atom** atoms;
245
246 // We are very careless here with the distinction between n_atoms and n_local
247 // We should really fix this before someone pokes an eye out.
248
249 n_atoms = entry_plug->n_atoms;
250 atoms = entry_plug->atoms;
251
252 mtot_local = 0.0;
253 vdrift_local[0] = 0.0;
254 vdrift_local[1] = 0.0;
255 vdrift_local[2] = 0.0;
256
257 for(vd = 0; vd < n_atoms; vd++){
258
259 vdrift_local[0] += atoms[vd]->get_vx() * atoms[vd]->getMass();
260 vdrift_local[1] += atoms[vd]->get_vy() * atoms[vd]->getMass();
261 vdrift_local[2] += atoms[vd]->get_vz() * atoms[vd]->getMass();
262
263 mtot_local += atoms[vd]->getMass();
264 }
265
266 #ifdef IS_MPI
267 MPI_Allreduce(&mtot_local,&mtot,1,MPI_DOUBLE,MPI_SUM, MPI_COMM_WORLD);
268 MPI_Allreduce(vdrift_local,vdrift,3,MPI_DOUBLE,MPI_SUM, MPI_COMM_WORLD);
269 #else
270 mtot = mtot_local;
271 for(vd = 0; vd < 3; vd++) {
272 vdrift[vd] = vdrift_local[vd];
273 }
274 #endif
275
276 for (vd = 0; vd < 3; vd++) {
277 vdrift[vd] = vdrift[vd] / mtot;
278 }
279
280 }
281