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root/group/trunk/OOPSE/libmdtools/Thermo.cpp
Revision: 582
Committed: Wed Jul 9 15:33:46 2003 UTC (21 years ago) by mmeineke
File size: 8349 byte(s)
Log Message:
adding in dan's NPT stuff

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