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root/group/trunk/OOPSE/libmdtools/Thermo.cpp
Revision: 611
Committed: Tue Jul 15 17:10:50 2003 UTC (20 years, 11 months ago) by gezelter
File size: 7755 byte(s)
Log Message:
Fixing  pressure tensor

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 kinetic;
37 double amass;
38 double aVel[3], aJ[3], I[3][3];
39 int j, kl;
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 atoms[kl]->getVel(aVel);
56 amass = atoms[kl]->getMass();
57
58 for (j=0; j < 3; j++)
59 kinetic += amass * aVel[j] * aVel[j];
60
61 if( atoms[kl]->isDirectional() ){
62
63 dAtom = (DirectionalAtom *)atoms[kl];
64
65 dAtom->getJ( aJ );
66 dAtom->getI( I );
67
68 for (j=0; j<3; j++)
69 kinetic += aJ[j]*aJ[j] / I[j][j];
70
71 }
72 }
73 #ifdef IS_MPI
74 MPI_Allreduce(&kinetic,&kinetic_global,1,MPI_DOUBLE,
75 MPI_SUM, MPI_COMM_WORLD);
76 kinetic = kinetic_global;
77 #endif //is_mpi
78
79 kinetic = kinetic * 0.5 / e_convert;
80
81 return kinetic;
82 }
83
84 double Thermo::getPotential(){
85
86 double potential_local;
87 double potential;
88 int el, nSRI;
89 Molecule* molecules;
90
91 molecules = entry_plug->molecules;
92 nSRI = entry_plug->n_SRI;
93
94 potential_local = 0.0;
95 potential = 0.0;
96 potential_local += entry_plug->lrPot;
97
98 for( el=0; el<entry_plug->n_mol; el++ ){
99 potential_local += molecules[el].getPotential();
100 }
101
102 // Get total potential for entire system from MPI.
103 #ifdef IS_MPI
104 MPI_Allreduce(&potential_local,&potential,1,MPI_DOUBLE,
105 MPI_SUM, MPI_COMM_WORLD);
106 #else
107 potential = potential_local;
108 #endif // is_mpi
109
110 #ifdef IS_MPI
111 /*
112 std::cerr << "node " << worldRank << ": after pot = " << potential << "\n";
113 */
114 #endif
115
116 return potential;
117 }
118
119 double Thermo::getTotalE(){
120
121 double total;
122
123 total = this->getKinetic() + this->getPotential();
124 return total;
125 }
126
127 double Thermo::getTemperature(){
128
129 const double kb = 1.9872179E-3; // boltzman's constant in kcal/(mol K)
130 double temperature;
131
132 temperature = ( 2.0 * this->getKinetic() ) / ((double)entry_plug->ndf * kb );
133 return temperature;
134 }
135
136 double Thermo::getEnthalpy() {
137
138 const double e_convert = 4.184E-4; // convert kcal/mol -> (amu A^2)/fs^2
139 double u, p, v;
140 double press[3][3];
141
142 u = this->getTotalE();
143
144 this->getPressureTensor(press);
145 p = (press[0][0] + press[1][1] + press[2][2]) / 3.0;
146
147 v = this->getVolume();
148
149 return (u + (p*v)/e_convert);
150 }
151
152 double Thermo::getVolume() {
153
154 return entry_plug->boxVol;
155 }
156
157 double Thermo::getPressure() {
158
159 // Relies on the calculation of the full molecular pressure tensor
160
161 const double p_convert = 1.63882576e8;
162 double press[3][3];
163 double pressure;
164
165 this->getPressureTensor(press);
166
167 pressure = p_convert * (press[0][0] + press[1][1] + press[2][2]) / 3.0;
168
169 return pressure;
170 }
171
172
173 void Thermo::getPressureTensor(double press[3][3]){
174 // returns pressure tensor in units amu*fs^-2*Ang^-1
175 // routine derived via viral theorem description in:
176 // Paci, E. and Marchi, M. J.Phys.Chem. 1996, 100, 4314-4322
177
178 const double e_convert = 4.184e-4;
179
180 double molmass, volume;
181 double vcom[3];
182 double p_local[9], p_global[9];
183 int i, j, k, l, nMols;
184 Molecule* molecules;
185
186 nMols = entry_plug->n_mol;
187 molecules = entry_plug->molecules;
188 //tau = entry_plug->tau;
189
190 // use velocities of molecular centers of mass and molecular masses:
191 for (i=0; i < 9; i++) {
192 p_local[i] = 0.0;
193 p_global[i] = 0.0;
194 }
195
196 for (i=0; i < nMols; i++) {
197 molmass = molecules[i].getCOMvel(vcom);
198
199 p_local[0] += molmass * (vcom[0] * vcom[0]);
200 p_local[1] += molmass * (vcom[0] * vcom[1]);
201 p_local[2] += molmass * (vcom[0] * vcom[2]);
202 p_local[3] += molmass * (vcom[1] * vcom[0]);
203 p_local[4] += molmass * (vcom[1] * vcom[1]);
204 p_local[5] += molmass * (vcom[1] * vcom[2]);
205 p_local[6] += molmass * (vcom[2] * vcom[0]);
206 p_local[7] += molmass * (vcom[2] * vcom[1]);
207 p_local[8] += molmass * (vcom[2] * vcom[2]);
208 }
209
210 // Get total for entire system from MPI.
211
212 #ifdef IS_MPI
213 MPI_Allreduce(p_local,p_global,9,MPI_DOUBLE, MPI_SUM, MPI_COMM_WORLD);
214 #else
215 for (i=0; i<9; i++) {
216 p_global[i] = p_local[i];
217 }
218 #endif // is_mpi
219
220 volume = this->getVolume();
221
222 for(i = 0; i < 3; i++) {
223 for (j = 0; j < 3; j++) {
224 k = 3*i + j;
225 press[i][j] = (p_global[k] + entry_plug->tau[k]*e_convert) / volume;
226 }
227 }
228 }
229
230 void Thermo::velocitize() {
231
232 double x,y;
233 double aVel[3], aJ[3], I[3][3];
234 int i, j, vr, vd; // velocity randomizer loop counters
235 double vdrift[3];
236 double vbar;
237 const double kb = 8.31451e-7; // kb in amu, angstroms, fs, etc.
238 double av2;
239 double kebar;
240 int n_atoms;
241 Atom** atoms;
242 DirectionalAtom* dAtom;
243 double temperature;
244 int n_oriented;
245 int n_constraints;
246
247 atoms = entry_plug->atoms;
248 n_atoms = entry_plug->n_atoms;
249 temperature = entry_plug->target_temp;
250 n_oriented = entry_plug->n_oriented;
251 n_constraints = entry_plug->n_constraints;
252
253 kebar = kb * temperature * (double)entry_plug->ndf /
254 ( 2.0 * (double)entry_plug->ndfRaw );
255
256 for(vr = 0; vr < n_atoms; vr++){
257
258 // uses equipartition theory to solve for vbar in angstrom/fs
259
260 av2 = 2.0 * kebar / atoms[vr]->getMass();
261 vbar = sqrt( av2 );
262
263 // vbar = sqrt( 8.31451e-7 * temperature / atoms[vr]->getMass() );
264
265 // picks random velocities from a gaussian distribution
266 // centered on vbar
267
268 for (j=0; j<3; j++)
269 aVel[j] = vbar * gaussStream->getGaussian();
270
271 atoms[vr]->setVel( aVel );
272
273 }
274
275 // Get the Center of Mass drift velocity.
276
277 getCOMVel(vdrift);
278
279 // Corrects for the center of mass drift.
280 // sums all the momentum and divides by total mass.
281
282 for(vd = 0; vd < n_atoms; vd++){
283
284 atoms[vd]->getVel(aVel);
285
286 for (j=0; j < 3; j++)
287 aVel[j] -= vdrift[j];
288
289 atoms[vd]->setVel( aVel );
290 }
291 if( n_oriented ){
292
293 for( i=0; i<n_atoms; i++ ){
294
295 if( atoms[i]->isDirectional() ){
296
297 dAtom = (DirectionalAtom *)atoms[i];
298 dAtom->getI( I );
299
300 for (j = 0 ; j < 3; j++) {
301
302 vbar = sqrt( 2.0 * kebar * I[j][j] );
303 aJ[j] = vbar * gaussStream->getGaussian();
304
305 }
306
307 dAtom->setJ( aJ );
308
309 }
310 }
311 }
312 }
313
314 void Thermo::getCOMVel(double vdrift[3]){
315
316 double mtot, mtot_local;
317 double aVel[3], amass;
318 double vdrift_local[3];
319 int vd, n_atoms, j;
320 Atom** atoms;
321
322 // We are very careless here with the distinction between n_atoms and n_local
323 // We should really fix this before someone pokes an eye out.
324
325 n_atoms = entry_plug->n_atoms;
326 atoms = entry_plug->atoms;
327
328 mtot_local = 0.0;
329 vdrift_local[0] = 0.0;
330 vdrift_local[1] = 0.0;
331 vdrift_local[2] = 0.0;
332
333 for(vd = 0; vd < n_atoms; vd++){
334
335 amass = atoms[vd]->getMass();
336 atoms[vd]->getVel( aVel );
337
338 for(j = 0; j < 3; j++)
339 vdrift_local[j] += aVel[j] * amass;
340
341 mtot_local += amass;
342 }
343
344 #ifdef IS_MPI
345 MPI_Allreduce(&mtot_local,&mtot,1,MPI_DOUBLE,MPI_SUM, MPI_COMM_WORLD);
346 MPI_Allreduce(vdrift_local,vdrift,3,MPI_DOUBLE,MPI_SUM, MPI_COMM_WORLD);
347 #else
348 mtot = mtot_local;
349 for(vd = 0; vd < 3; vd++) {
350 vdrift[vd] = vdrift_local[vd];
351 }
352 #endif
353
354 for (vd = 0; vd < 3; vd++) {
355 vdrift[vd] = vdrift[vd] / mtot;
356 }
357
358 }
359