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root/group/trunk/OOPSE/libmdtools/Thermo.cpp
Revision: 574
Committed: Tue Jul 8 20:56:10 2003 UTC (21 years ago) by gezelter
File size: 8632 byte(s)
Log Message:
NPTi

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::getEnthalpy() {
138
139 const double e_convert = 4.184E-4; // convert kcal/mol -> (amu A^2)/fs^2
140 double u, p, v;
141 double press[9];
142
143 u = this->getTotalE();
144
145 this->getPressureTensor(press);
146 p = (press[0] + press[4] + press[8]) / 3.0;
147
148 v = this->getVolume();
149
150 return (u + (p*v)/e_convert);
151 }
152
153 double Thermo::getVolume() {
154
155 double volume;
156 double Hmat[9];
157
158 entry_plug->getBoxM(Hmat);
159
160 // volume = h1 (dot) h2 (cross) h3
161
162 volume = Hmat[0] * ( (Hmat[4]*Hmat[8]) - (Hmat[7]*Hmat[5]) )
163 + Hmat[1] * ( (Hmat[5]*Hmat[6]) - (Hmat[8]*Hmat[3]) )
164 + Hmat[2] * ( (Hmat[3]*Hmat[7]) - (Hmat[6]*Hmat[4]) );
165
166 return volume;
167 }
168
169 double Thermo::getPressure() {
170
171 // Relies on the calculation of the full molecular pressure tensor
172
173 const double p_convert = 1.63882576e8;
174 double press[9];
175 double pressure;
176
177 this->getPressureTensor(press);
178
179 pressure = p_convert * (press[0] + press[4] + press[8]) / 3.0;
180
181 return pressure;
182 }
183
184
185 void Thermo::getPressureTensor(double press[9]){
186 // returns pressure tensor in units amu*fs^-2*Ang^-1
187 // routine derived via viral theorem description in:
188 // Paci, E. and Marchi, M. J.Phys.Chem. 1996, 100, 4314-4322
189
190 const double e_convert = 4.184e-4;
191
192 double molmass, volume;
193 double vcom[3];
194 double p_local[9], p_global[9];
195 double theBox[3];
196 //double* tau;
197 int i, nMols;
198 Molecule* molecules;
199
200 nMols = entry_plug->n_mol;
201 molecules = entry_plug->molecules;
202 //tau = entry_plug->tau;
203
204 // use velocities of molecular centers of mass and molecular masses:
205 for (i=0; i < 9; i++) {
206 p_local[i] = 0.0;
207 p_global[i] = 0.0;
208 }
209
210 for (i=0; i < nMols; i++) {
211 molmass = molecules[i].getCOMvel(vcom);
212
213 p_local[0] += molmass * (vcom[0] * vcom[0]);
214 p_local[1] += molmass * (vcom[0] * vcom[1]);
215 p_local[2] += molmass * (vcom[0] * vcom[2]);
216 p_local[3] += molmass * (vcom[1] * vcom[0]);
217 p_local[4] += molmass * (vcom[1] * vcom[1]);
218 p_local[5] += molmass * (vcom[1] * vcom[2]);
219 p_local[6] += molmass * (vcom[2] * vcom[0]);
220 p_local[7] += molmass * (vcom[2] * vcom[1]);
221 p_local[8] += molmass * (vcom[2] * vcom[2]);
222 }
223
224 // Get total for entire system from MPI.
225
226 #ifdef IS_MPI
227 MPI_Allreduce(p_local,p_global,9,MPI_DOUBLE, MPI_SUM, MPI_COMM_WORLD);
228 #else
229 for (i=0; i<9; i++) {
230 p_global[i] = p_local[i];
231 }
232 #endif // is_mpi
233
234 volume = entry_plug->boxVol;
235
236 for(i=0; i<9; i++) {
237 press[i] = (p_global[i] - entry_plug->tau[i]*e_convert) / volume;
238 }
239 }
240
241 void Thermo::velocitize() {
242
243 double x,y;
244 double vx, vy, vz;
245 double jx, jy, jz;
246 int i, vr, vd; // velocity randomizer loop counters
247 double vdrift[3];
248 double vbar;
249 const double kb = 8.31451e-7; // kb in amu, angstroms, fs, etc.
250 double av2;
251 double kebar;
252 int n_atoms;
253 Atom** atoms;
254 DirectionalAtom* dAtom;
255 double temperature;
256 int n_oriented;
257 int n_constraints;
258
259 atoms = entry_plug->atoms;
260 n_atoms = entry_plug->n_atoms;
261 temperature = entry_plug->target_temp;
262 n_oriented = entry_plug->n_oriented;
263 n_constraints = entry_plug->n_constraints;
264
265 kebar = kb * temperature * (double)entry_plug->ndf /
266 ( 2.0 * (double)entry_plug->ndfRaw );
267
268 for(vr = 0; vr < n_atoms; vr++){
269
270 // uses equipartition theory to solve for vbar in angstrom/fs
271
272 av2 = 2.0 * kebar / atoms[vr]->getMass();
273 vbar = sqrt( av2 );
274
275 // vbar = sqrt( 8.31451e-7 * temperature / atoms[vr]->getMass() );
276
277 // picks random velocities from a gaussian distribution
278 // centered on vbar
279
280 vx = vbar * gaussStream->getGaussian();
281 vy = vbar * gaussStream->getGaussian();
282 vz = vbar * gaussStream->getGaussian();
283
284 atoms[vr]->set_vx( vx );
285 atoms[vr]->set_vy( vy );
286 atoms[vr]->set_vz( vz );
287 }
288
289 // Get the Center of Mass drift velocity.
290
291 getCOMVel(vdrift);
292
293 // Corrects for the center of mass drift.
294 // sums all the momentum and divides by total mass.
295
296 for(vd = 0; vd < n_atoms; vd++){
297
298 vx = atoms[vd]->get_vx();
299 vy = atoms[vd]->get_vy();
300 vz = atoms[vd]->get_vz();
301
302 vx -= vdrift[0];
303 vy -= vdrift[1];
304 vz -= vdrift[2];
305
306 atoms[vd]->set_vx(vx);
307 atoms[vd]->set_vy(vy);
308 atoms[vd]->set_vz(vz);
309 }
310 if( n_oriented ){
311
312 for( i=0; i<n_atoms; i++ ){
313
314 if( atoms[i]->isDirectional() ){
315
316 dAtom = (DirectionalAtom *)atoms[i];
317
318 vbar = sqrt( 2.0 * kebar * dAtom->getIxx() );
319 jx = vbar * gaussStream->getGaussian();
320
321 vbar = sqrt( 2.0 * kebar * dAtom->getIyy() );
322 jy = vbar * gaussStream->getGaussian();
323
324 vbar = sqrt( 2.0 * kebar * dAtom->getIzz() );
325 jz = vbar * gaussStream->getGaussian();
326
327 dAtom->setJx( jx );
328 dAtom->setJy( jy );
329 dAtom->setJz( jz );
330 }
331 }
332 }
333 }
334
335 void Thermo::getCOMVel(double vdrift[3]){
336
337 double mtot, mtot_local;
338 double vdrift_local[3];
339 int vd, n_atoms;
340 Atom** atoms;
341
342 // We are very careless here with the distinction between n_atoms and n_local
343 // We should really fix this before someone pokes an eye out.
344
345 n_atoms = entry_plug->n_atoms;
346 atoms = entry_plug->atoms;
347
348 mtot_local = 0.0;
349 vdrift_local[0] = 0.0;
350 vdrift_local[1] = 0.0;
351 vdrift_local[2] = 0.0;
352
353 for(vd = 0; vd < n_atoms; vd++){
354
355 vdrift_local[0] += atoms[vd]->get_vx() * atoms[vd]->getMass();
356 vdrift_local[1] += atoms[vd]->get_vy() * atoms[vd]->getMass();
357 vdrift_local[2] += atoms[vd]->get_vz() * atoms[vd]->getMass();
358
359 mtot_local += atoms[vd]->getMass();
360 }
361
362 #ifdef IS_MPI
363 MPI_Allreduce(&mtot_local,&mtot,1,MPI_DOUBLE,MPI_SUM, MPI_COMM_WORLD);
364 MPI_Allreduce(vdrift_local,vdrift,3,MPI_DOUBLE,MPI_SUM, MPI_COMM_WORLD);
365 #else
366 mtot = mtot_local;
367 for(vd = 0; vd < 3; vd++) {
368 vdrift[vd] = vdrift_local[vd];
369 }
370 #endif
371
372 for (vd = 0; vd < 3; vd++) {
373 vdrift[vd] = vdrift[vd] / mtot;
374 }
375
376 }
377