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root/group/trunk/OOPSE/libmdtools/Thermo.cpp
Revision: 483
Committed: Wed Apr 9 04:06:43 2003 UTC (21 years, 3 months ago) by gezelter
File size: 8045 byte(s)
Log Message:
fixes for NPT and NVT

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 the pressure in units of atm
139 // Relies on the calculation of the full molecular pressure tensor
140
141 const double p_convert = 1.63882576e8;
142 double press[9];
143 double pressure;
144
145 this->getPressureTensor(press);
146
147 pressure = p_convert * (press[0] + press[4] + press[8]) / 3.0;
148
149 return pressure;
150 }
151
152
153 void Thermo::getPressureTensor(double press[9]){
154 // returns pressure tensor in units amu*fs^-2*Ang^-1
155 // routine derived via viral theorem description in:
156 // Paci, E. and Marchi, M. J.Phys.Chem. 1996, 100, 4314-4322
157
158 const double e_convert = 4.184e-4;
159
160 double molmass, volume;
161 double vcom[3];
162 double p_local[9], p_global[9];
163 double theBox[3];
164 double* tau;
165 int i, nMols;
166 Molecule* molecules;
167
168 nMols = entry_plug->n_mol;
169 molecules = entry_plug->molecules;
170 tau = entry_plug->tau;
171
172 // use velocities of molecular centers of mass and molecular masses:
173 for (i=0; i < 9; i++) {
174 p_local[i] = 0.0;
175 p_global[i] = 0.0;
176 }
177
178 for (i=0; i < nMols; i++) {
179 molmass = molecules[i].getCOMvel(vcom);
180
181 p_local[0] += molmass * (vcom[0] * vcom[0]);
182 p_local[1] += molmass * (vcom[0] * vcom[1]);
183 p_local[2] += molmass * (vcom[0] * vcom[2]);
184 p_local[3] += molmass * (vcom[1] * vcom[0]);
185 p_local[4] += molmass * (vcom[1] * vcom[1]);
186 p_local[5] += molmass * (vcom[1] * vcom[2]);
187 p_local[6] += molmass * (vcom[2] * vcom[0]);
188 p_local[7] += molmass * (vcom[2] * vcom[1]);
189 p_local[8] += molmass * (vcom[2] * vcom[2]);
190 }
191
192 // Get total for entire system from MPI.
193
194 #ifdef IS_MPI
195 MPI_Allreduce(p_local,p_global,9,MPI_DOUBLE, MPI_SUM, MPI_COMM_WORLD);
196 #else
197 for (i=0; i<9; i++) {
198 p_global[i] = p_local[i];
199 }
200 #endif // is_mpi
201
202 entry_plug->getBox(theBox);
203
204 volume = theBox[0] * theBox[1] * theBox[2];
205
206 for(i=0; i<9; i++) {
207 press[i] = (p_global[i] - tau[i]*e_convert) / volume;
208 }
209 }
210
211 void Thermo::velocitize() {
212
213 double x,y;
214 double vx, vy, vz;
215 double jx, jy, jz;
216 int i, vr, vd; // velocity randomizer loop counters
217 double vdrift[3];
218 double vbar;
219 const double kb = 8.31451e-7; // kb in amu, angstroms, fs, etc.
220 double av2;
221 double kebar;
222 int n_atoms;
223 Atom** atoms;
224 DirectionalAtom* dAtom;
225 double temperature;
226 int n_oriented;
227 int n_constraints;
228
229 atoms = entry_plug->atoms;
230 n_atoms = entry_plug->n_atoms;
231 temperature = entry_plug->target_temp;
232 n_oriented = entry_plug->n_oriented;
233 n_constraints = entry_plug->n_constraints;
234
235 kebar = kb * temperature * (double)entry_plug->ndf /
236 ( 2.0 * (double)entry_plug->ndfRaw );
237
238 for(vr = 0; vr < n_atoms; vr++){
239
240 // uses equipartition theory to solve for vbar in angstrom/fs
241
242 av2 = 2.0 * kebar / atoms[vr]->getMass();
243 vbar = sqrt( av2 );
244
245 // vbar = sqrt( 8.31451e-7 * temperature / atoms[vr]->getMass() );
246
247 // picks random velocities from a gaussian distribution
248 // centered on vbar
249
250 vx = vbar * gaussStream->getGaussian();
251 vy = vbar * gaussStream->getGaussian();
252 vz = vbar * gaussStream->getGaussian();
253
254 atoms[vr]->set_vx( vx );
255 atoms[vr]->set_vy( vy );
256 atoms[vr]->set_vz( vz );
257 }
258
259 // Get the Center of Mass drift velocity.
260
261 getCOMVel(vdrift);
262
263 // Corrects for the center of mass drift.
264 // sums all the momentum and divides by total mass.
265
266 for(vd = 0; vd < n_atoms; vd++){
267
268 vx = atoms[vd]->get_vx();
269 vy = atoms[vd]->get_vy();
270 vz = atoms[vd]->get_vz();
271
272 vx -= vdrift[0];
273 vy -= vdrift[1];
274 vz -= vdrift[2];
275
276 atoms[vd]->set_vx(vx);
277 atoms[vd]->set_vy(vy);
278 atoms[vd]->set_vz(vz);
279 }
280 if( n_oriented ){
281
282 for( i=0; i<n_atoms; i++ ){
283
284 if( atoms[i]->isDirectional() ){
285
286 dAtom = (DirectionalAtom *)atoms[i];
287
288 vbar = sqrt( 2.0 * kebar * dAtom->getIxx() );
289 jx = vbar * gaussStream->getGaussian();
290
291 vbar = sqrt( 2.0 * kebar * dAtom->getIyy() );
292 jy = vbar * gaussStream->getGaussian();
293
294 vbar = sqrt( 2.0 * kebar * dAtom->getIzz() );
295 jz = vbar * gaussStream->getGaussian();
296
297 dAtom->setJx( jx );
298 dAtom->setJy( jy );
299 dAtom->setJz( jz );
300 }
301 }
302 }
303 }
304
305 void Thermo::getCOMVel(double vdrift[3]){
306
307 double mtot, mtot_local;
308 double vdrift_local[3];
309 int vd, n_atoms;
310 Atom** atoms;
311
312 // We are very careless here with the distinction between n_atoms and n_local
313 // We should really fix this before someone pokes an eye out.
314
315 n_atoms = entry_plug->n_atoms;
316 atoms = entry_plug->atoms;
317
318 mtot_local = 0.0;
319 vdrift_local[0] = 0.0;
320 vdrift_local[1] = 0.0;
321 vdrift_local[2] = 0.0;
322
323 for(vd = 0; vd < n_atoms; vd++){
324
325 vdrift_local[0] += atoms[vd]->get_vx() * atoms[vd]->getMass();
326 vdrift_local[1] += atoms[vd]->get_vy() * atoms[vd]->getMass();
327 vdrift_local[2] += atoms[vd]->get_vz() * atoms[vd]->getMass();
328
329 mtot_local += atoms[vd]->getMass();
330 }
331
332 #ifdef IS_MPI
333 MPI_Allreduce(&mtot_local,&mtot,1,MPI_DOUBLE,MPI_SUM, MPI_COMM_WORLD);
334 MPI_Allreduce(vdrift_local,vdrift,3,MPI_DOUBLE,MPI_SUM, MPI_COMM_WORLD);
335 #else
336 mtot = mtot_local;
337 for(vd = 0; vd < 3; vd++) {
338 vdrift[vd] = vdrift_local[vd];
339 }
340 #endif
341
342 for (vd = 0; vd < 3; vd++) {
343 vdrift[vd] = vdrift[vd] / mtot;
344 }
345
346 }
347