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root/group/trunk/OOPSE/libmdtools/NPTf.cpp
Revision: 778
Committed: Fri Sep 19 20:00:27 2003 UTC (20 years, 9 months ago) by mmeineke
File size: 12519 byte(s)
Log Message:
added NPT base class. NPTi is up to date. NPTf is not.

File Contents

# Content
1 #include <cmath>
2 #include "Atom.hpp"
3 #include "SRI.hpp"
4 #include "AbstractClasses.hpp"
5 #include "SimInfo.hpp"
6 #include "ForceFields.hpp"
7 #include "Thermo.hpp"
8 #include "ReadWrite.hpp"
9 #include "Integrator.hpp"
10 #include "simError.h"
11
12 #ifdef IS_MPI
13 #include "mpiSimulation.hpp"
14 #endif
15
16 // Basic non-isotropic thermostating and barostating via the Melchionna
17 // modification of the Hoover algorithm:
18 //
19 // Melchionna, S., Ciccotti, G., and Holian, B. L., 1993,
20 // Molec. Phys., 78, 533.
21 //
22 // and
23 //
24 // Hoover, W. G., 1986, Phys. Rev. A, 34, 2499.
25
26 template<typename T> NPTf<T>::NPTf ( SimInfo *theInfo, ForceFields* the_ff):
27 T( theInfo, the_ff )
28 {
29 int i, j;
30 chi = 0.0;
31 integralOfChidt = 0.0;
32
33 for(i = 0; i < 3; i++)
34 for (j = 0; j < 3; j++)
35 eta[i][j] = 0.0;
36
37 have_tau_thermostat = 0;
38 have_tau_barostat = 0;
39 have_target_temp = 0;
40 have_target_pressure = 0;
41
42 have_chi_tolerance = 0;
43 have_eta_tolerance = 0;
44 have_pos_iter_tolerance = 0;
45
46 oldPos = new double[3*nAtoms];
47 oldVel = new double[3*nAtoms];
48 oldJi = new double[3*nAtoms];
49 #ifdef IS_MPI
50 Nparticles = mpiSim->getTotAtoms();
51 #else
52 Nparticles = theInfo->n_atoms;
53 #endif
54
55 }
56
57 template<typename T> NPTf<T>::~NPTf() {
58 delete[] oldPos;
59 delete[] oldVel;
60 delete[] oldJi;
61 }
62
63 template<typename T> void NPTf<T>::moveA() {
64
65 // new version of NPTf
66 int i, j, k;
67 DirectionalAtom* dAtom;
68 double Tb[3], ji[3];
69
70 double mass;
71 double vel[3], pos[3], frc[3];
72
73 double rj[3];
74 double instaTemp, instaPress, instaVol;
75 double tt2, tb2;
76 double sc[3];
77 double eta2ij;
78 double press[3][3], vScale[3][3], hm[3][3], hmnew[3][3], scaleMat[3][3];
79 double bigScale, smallScale, offDiagMax;
80 double COM[3];
81
82 tt2 = tauThermostat * tauThermostat;
83 tb2 = tauBarostat * tauBarostat;
84
85 instaTemp = tStats->getTemperature();
86 tStats->getPressureTensor(press);
87 instaVol = tStats->getVolume();
88
89 tStats->getCOM(COM);
90
91 //calculate scale factor of veloity
92 for (i = 0; i < 3; i++ ) {
93 for (j = 0; j < 3; j++ ) {
94 vScale[i][j] = eta[i][j];
95
96 if (i == j) {
97 vScale[i][j] += chi;
98 }
99 }
100 }
101
102 //evolve velocity half step
103 for( i=0; i<nAtoms; i++ ){
104
105 atoms[i]->getVel( vel );
106 atoms[i]->getFrc( frc );
107
108 mass = atoms[i]->getMass();
109
110 info->matVecMul3( vScale, vel, sc );
111
112 for (j=0; j < 3; j++) {
113 // velocity half step
114 vel[j] += dt2 * ((frc[j] / mass) * eConvert - sc[j]);
115 }
116
117 atoms[i]->setVel( vel );
118
119 if( atoms[i]->isDirectional() ){
120
121 dAtom = (DirectionalAtom *)atoms[i];
122
123 // get and convert the torque to body frame
124
125 dAtom->getTrq( Tb );
126 dAtom->lab2Body( Tb );
127
128 // get the angular momentum, and propagate a half step
129
130 dAtom->getJ( ji );
131
132 for (j=0; j < 3; j++)
133 ji[j] += dt2 * (Tb[j] * eConvert - ji[j]*chi);
134
135 this->rotationPropagation( dAtom, ji );
136
137 dAtom->setJ( ji );
138 }
139 }
140
141 // advance chi half step
142 chi += dt2 * ( instaTemp / targetTemp - 1.0) / tt2;
143
144 // calculate the integral of chidt
145 integralOfChidt += dt2*chi;
146
147 // advance eta half step
148
149 for(i = 0; i < 3; i ++)
150 for(j = 0; j < 3; j++){
151 if( i == j)
152 eta[i][j] += dt2 * instaVol *
153 (press[i][j] - targetPressure/p_convert) / (NkBT*tb2);
154 else
155 eta[i][j] += dt2 * instaVol * press[i][j] / (NkBT*tb2);
156 }
157
158 //save the old positions
159 for(i = 0; i < nAtoms; i++){
160 atoms[i]->getPos(pos);
161 for(j = 0; j < 3; j++)
162 oldPos[i*3 + j] = pos[j];
163 }
164
165 //the first estimation of r(t+dt) is equal to r(t)
166
167 for(k = 0; k < 4; k ++){
168
169 for(i =0 ; i < nAtoms; i++){
170
171 atoms[i]->getVel(vel);
172 atoms[i]->getPos(pos);
173
174 for(j = 0; j < 3; j++)
175 rj[j] = (oldPos[i*3 + j] + pos[j])/2 - COM[j];
176
177 info->matVecMul3( eta, rj, sc );
178
179 for(j = 0; j < 3; j++)
180 pos[j] = oldPos[i*3 + j] + dt*(vel[j] + sc[j]);
181
182 atoms[i]->setPos( pos );
183
184 }
185
186 if (nConstrained) {
187 constrainA();
188 }
189 }
190
191
192 // Scale the box after all the positions have been moved:
193
194 // Use a taylor expansion for eta products: Hmat = Hmat . exp(dt * etaMat)
195 // Hmat = Hmat . ( Ident + dt * etaMat + dt^2 * etaMat*etaMat / 2)
196
197 bigScale = 1.0;
198 smallScale = 1.0;
199 offDiagMax = 0.0;
200
201 for(i=0; i<3; i++){
202 for(j=0; j<3; j++){
203
204 // Calculate the matrix Product of the eta array (we only need
205 // the ij element right now):
206
207 eta2ij = 0.0;
208 for(k=0; k<3; k++){
209 eta2ij += eta[i][k] * eta[k][j];
210 }
211
212 scaleMat[i][j] = 0.0;
213 // identity matrix (see above):
214 if (i == j) scaleMat[i][j] = 1.0;
215 // Taylor expansion for the exponential truncated at second order:
216 scaleMat[i][j] += dt*eta[i][j] + 0.5*dt*dt*eta2ij;
217
218 if (i != j)
219 if (fabs(scaleMat[i][j]) > offDiagMax)
220 offDiagMax = fabs(scaleMat[i][j]);
221 }
222
223 if (scaleMat[i][i] > bigScale) bigScale = scaleMat[i][i];
224 if (scaleMat[i][i] < smallScale) smallScale = scaleMat[i][i];
225 }
226
227 if ((bigScale > 1.1) || (smallScale < 0.9)) {
228 sprintf( painCave.errMsg,
229 "NPTf error: Attempting a Box scaling of more than 10 percent.\n"
230 " Check your tauBarostat, as it is probably too small!\n\n"
231 " scaleMat = [%lf\t%lf\t%lf]\n"
232 " [%lf\t%lf\t%lf]\n"
233 " [%lf\t%lf\t%lf]\n",
234 scaleMat[0][0],scaleMat[0][1],scaleMat[0][2],
235 scaleMat[1][0],scaleMat[1][1],scaleMat[1][2],
236 scaleMat[2][0],scaleMat[2][1],scaleMat[2][2]);
237 painCave.isFatal = 1;
238 simError();
239 } else if (offDiagMax > 0.1) {
240 sprintf( painCave.errMsg,
241 "NPTf error: Attempting an off-diagonal Box scaling of more than 10 percent.\n"
242 " Check your tauBarostat, as it is probably too small!\n\n"
243 " scaleMat = [%lf\t%lf\t%lf]\n"
244 " [%lf\t%lf\t%lf]\n"
245 " [%lf\t%lf\t%lf]\n",
246 scaleMat[0][0],scaleMat[0][1],scaleMat[0][2],
247 scaleMat[1][0],scaleMat[1][1],scaleMat[1][2],
248 scaleMat[2][0],scaleMat[2][1],scaleMat[2][2]);
249 painCave.isFatal = 1;
250 simError();
251 } else {
252 info->getBoxM(hm);
253 info->matMul3(hm, scaleMat, hmnew);
254 info->setBoxM(hmnew);
255 }
256
257 }
258
259 template<typename T> void NPTf<T>::moveB( void ){
260
261 //new version of NPTf
262 int i, j, k;
263 DirectionalAtom* dAtom;
264 double Tb[3], ji[3];
265 double vel[3], myVel[3], frc[3];
266 double mass;
267
268 double instaTemp, instaPress, instaVol;
269 double tt2, tb2;
270 double sc[3];
271 double press[3][3], vScale[3][3];
272 double oldChi, prevChi;
273 double oldEta[3][3], prevEta[3][3], diffEta;
274
275 tt2 = tauThermostat * tauThermostat;
276 tb2 = tauBarostat * tauBarostat;
277
278 // Set things up for the iteration:
279
280 oldChi = chi;
281
282 for(i = 0; i < 3; i++)
283 for(j = 0; j < 3; j++)
284 oldEta[i][j] = eta[i][j];
285
286 for( i=0; i<nAtoms; i++ ){
287
288 atoms[i]->getVel( vel );
289
290 for (j=0; j < 3; j++)
291 oldVel[3*i + j] = vel[j];
292
293 if( atoms[i]->isDirectional() ){
294
295 dAtom = (DirectionalAtom *)atoms[i];
296
297 dAtom->getJ( ji );
298
299 for (j=0; j < 3; j++)
300 oldJi[3*i + j] = ji[j];
301
302 }
303 }
304
305 // do the iteration:
306
307 instaVol = tStats->getVolume();
308
309 for (k=0; k < 4; k++) {
310
311 instaTemp = tStats->getTemperature();
312 tStats->getPressureTensor(press);
313
314 // evolve chi another half step using the temperature at t + dt/2
315
316 prevChi = chi;
317 chi = oldChi + dt2 * ( instaTemp / targetTemp - 1.0) / tt2;
318
319 for(i = 0; i < 3; i++)
320 for(j = 0; j < 3; j++)
321 prevEta[i][j] = eta[i][j];
322
323 //advance eta half step and calculate scale factor for velocity
324
325 for(i = 0; i < 3; i ++)
326 for(j = 0; j < 3; j++){
327 if( i == j) {
328 eta[i][j] = oldEta[i][j] + dt2 * instaVol *
329 (press[i][j] - targetPressure/p_convert) / (NkBT*tb2);
330 vScale[i][j] = eta[i][j] + chi;
331 } else {
332 eta[i][j] = oldEta[i][j] + dt2 * instaVol * press[i][j] / (NkBT*tb2);
333 vScale[i][j] = eta[i][j];
334 }
335 }
336
337 for( i=0; i<nAtoms; i++ ){
338
339 atoms[i]->getFrc( frc );
340 atoms[i]->getVel(vel);
341
342 mass = atoms[i]->getMass();
343
344 for (j = 0; j < 3; j++)
345 myVel[j] = oldVel[3*i + j];
346
347 info->matVecMul3( vScale, myVel, sc );
348
349 // velocity half step
350 for (j=0; j < 3; j++) {
351 // velocity half step (use chi from previous step here):
352 vel[j] = oldVel[3*i+j] + dt2 * ((frc[j] / mass) * eConvert - sc[j]);
353 }
354
355 atoms[i]->setVel( vel );
356
357 if( atoms[i]->isDirectional() ){
358
359 dAtom = (DirectionalAtom *)atoms[i];
360
361 // get and convert the torque to body frame
362
363 dAtom->getTrq( Tb );
364 dAtom->lab2Body( Tb );
365
366 for (j=0; j < 3; j++)
367 ji[j] = oldJi[3*i + j] + dt2 * (Tb[j] * eConvert - oldJi[3*i+j]*chi);
368
369 dAtom->setJ( ji );
370 }
371 }
372
373 if (nConstrained) {
374 constrainB();
375 }
376
377 diffEta = 0;
378 for(i = 0; i < 3; i++)
379 diffEta += pow(prevEta[i][i] - eta[i][i], 2);
380
381 if (fabs(prevChi - chi) <= chiTolerance && sqrt(diffEta / 3) <= etaTolerance)
382 break;
383 }
384
385 //calculate integral of chidt
386 integralOfChidt += dt2*chi;
387
388 }
389
390 template<typename T> void NPTf<T>::resetIntegrator() {
391 int i,j;
392
393 chi = 0.0;
394
395 for(i = 0; i < 3; i++)
396 for (j = 0; j < 3; j++)
397 eta[i][j] = 0.0;
398
399 }
400
401 template<typename T> int NPTf<T>::readyCheck() {
402
403 //check parent's readyCheck() first
404 if (T::readyCheck() == -1)
405 return -1;
406
407 // First check to see if we have a target temperature.
408 // Not having one is fatal.
409
410 if (!have_target_temp) {
411 sprintf( painCave.errMsg,
412 "NPTf error: You can't use the NPTf integrator\n"
413 " without a targetTemp!\n"
414 );
415 painCave.isFatal = 1;
416 simError();
417 return -1;
418 }
419
420 if (!have_target_pressure) {
421 sprintf( painCave.errMsg,
422 "NPTf error: You can't use the NPTf integrator\n"
423 " without a targetPressure!\n"
424 );
425 painCave.isFatal = 1;
426 simError();
427 return -1;
428 }
429
430 // We must set tauThermostat.
431
432 if (!have_tau_thermostat) {
433 sprintf( painCave.errMsg,
434 "NPTf error: If you use the NPTf\n"
435 " integrator, you must set tauThermostat.\n");
436 painCave.isFatal = 1;
437 simError();
438 return -1;
439 }
440
441 // We must set tauBarostat.
442
443 if (!have_tau_barostat) {
444 sprintf( painCave.errMsg,
445 "NPTf error: If you use the NPTf\n"
446 " integrator, you must set tauBarostat.\n");
447 painCave.isFatal = 1;
448 simError();
449 return -1;
450 }
451
452
453 // We need NkBT a lot, so just set it here: This is the RAW number
454 // of particles, so no subtraction or addition of constraints or
455 // orientational degrees of freedom:
456
457 NkBT = (double)Nparticles * kB * targetTemp;
458
459 // fkBT is used because the thermostat operates on more degrees of freedom
460 // than the barostat (when there are particles with orientational degrees
461 // of freedom). ndf = 3 * (n_atoms + n_oriented -1) - n_constraint - nZcons
462
463 fkBT = (double)info->ndf * kB * targetTemp;
464
465 return 1;
466 }
467
468 template<typename T> double NPTf<T>::getConservedQuantity(void){
469
470 double conservedQuantity;
471 double Energy;
472 double thermostat_kinetic;
473 double thermostat_potential;
474 double barostat_kinetic;
475 double barostat_potential;
476 double trEta;
477 double a[3][3], b[3][3];
478
479 Energy = tStats->getTotalE();
480
481 thermostat_kinetic = fkBT* tauThermostat * tauThermostat * chi * chi /
482 (2.0 * eConvert);
483
484 thermostat_potential = fkBT* integralOfChidt / eConvert;
485
486 info->transposeMat3(eta, a);
487 info->matMul3(a, eta, b);
488 trEta = info->matTrace3(b);
489
490 barostat_kinetic = NkBT * tauBarostat * tauBarostat * trEta /
491 (2.0 * eConvert);
492
493 barostat_potential = (targetPressure * tStats->getVolume() / p_convert) /
494 eConvert;
495
496 conservedQuantity = Energy + thermostat_kinetic + thermostat_potential +
497 barostat_kinetic + barostat_potential;
498
499 cout.width(8);
500 cout.precision(8);
501
502 cerr << info->getTime() << "\t" << Energy << "\t" << thermostat_kinetic <<
503 "\t" << thermostat_potential << "\t" << barostat_kinetic <<
504 "\t" << barostat_potential << "\t" << conservedQuantity << endl;
505
506 return conservedQuantity;
507 }