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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

# User Rev Content
1 gezelter 617 #include <cmath>
2 gezelter 576 #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 gezelter 772 #ifdef IS_MPI
13     #include "mpiSimulation.hpp"
14     #endif
15 gezelter 576
16 gezelter 578 // Basic non-isotropic thermostating and barostating via the Melchionna
17 gezelter 576 // 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 tim 645 template<typename T> NPTf<T>::NPTf ( SimInfo *theInfo, ForceFields* the_ff):
27     T( theInfo, the_ff )
28 gezelter 576 {
29 gezelter 588 int i, j;
30 gezelter 576 chi = 0.0;
31 tim 763 integralOfChidt = 0.0;
32 gezelter 588
33     for(i = 0; i < 3; i++)
34 mmeineke 590 for (j = 0; j < 3; j++)
35 gezelter 588 eta[i][j] = 0.0;
36    
37 gezelter 576 have_tau_thermostat = 0;
38     have_tau_barostat = 0;
39     have_target_temp = 0;
40     have_target_pressure = 0;
41 tim 767
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 gezelter 772
55 gezelter 576 }
56    
57 tim 767 template<typename T> NPTf<T>::~NPTf() {
58     delete[] oldPos;
59     delete[] oldVel;
60     delete[] oldJi;
61     }
62    
63 tim 645 template<typename T> void NPTf<T>::moveA() {
64 gezelter 772
65     // new version of NPTf
66 gezelter 600 int i, j, k;
67 gezelter 576 DirectionalAtom* dAtom;
68 gezelter 600 double Tb[3], ji[3];
69 mmeineke 778
70     double mass;
71 gezelter 600 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 gezelter 588 double press[3][3], vScale[3][3], hm[3][3], hmnew[3][3], scaleMat[3][3];
79 gezelter 617 double bigScale, smallScale, offDiagMax;
80 tim 767 double COM[3];
81 gezelter 576
82     tt2 = tauThermostat * tauThermostat;
83     tb2 = tauBarostat * tauBarostat;
84    
85     instaTemp = tStats->getTemperature();
86 gezelter 577 tStats->getPressureTensor(press);
87 gezelter 576 instaVol = tStats->getVolume();
88    
89 tim 767 tStats->getCOM(COM);
90 gezelter 588
91 tim 767 //calculate scale factor of veloity
92 gezelter 588 for (i = 0; i < 3; i++ ) {
93     for (j = 0; j < 3; j++ ) {
94 tim 767 vScale[i][j] = eta[i][j];
95    
96 gezelter 588 if (i == j) {
97 tim 767 vScale[i][j] += chi;
98     }
99 gezelter 588 }
100     }
101 tim 767
102     //evolve velocity half step
103 gezelter 576 for( i=0; i<nAtoms; i++ ){
104 gezelter 600
105     atoms[i]->getVel( vel );
106     atoms[i]->getFrc( frc );
107    
108     mass = atoms[i]->getMass();
109 gezelter 576
110 gezelter 600 info->matVecMul3( vScale, vel, sc );
111 tim 767
112     for (j=0; j < 3; j++) {
113 gezelter 772 // velocity half step
114 gezelter 600 vel[j] += dt2 * ((frc[j] / mass) * eConvert - sc[j]);
115     }
116 gezelter 576
117 gezelter 600 atoms[i]->setVel( vel );
118 gezelter 576
119     if( atoms[i]->isDirectional() ){
120    
121     dAtom = (DirectionalAtom *)atoms[i];
122 tim 767
123 gezelter 576 // get and convert the torque to body frame
124    
125 gezelter 600 dAtom->getTrq( Tb );
126 gezelter 576 dAtom->lab2Body( Tb );
127    
128     // get the angular momentum, and propagate a half step
129    
130 gezelter 600 dAtom->getJ( ji );
131    
132     for (j=0; j < 3; j++)
133     ji[j] += dt2 * (Tb[j] * eConvert - ji[j]*chi);
134 gezelter 576
135 mmeineke 778 this->rotationPropagation( dAtom, ji );
136    
137 gezelter 600 dAtom->setJ( ji );
138 tim 767 }
139 gezelter 576 }
140 tim 767
141     // advance chi half step
142     chi += dt2 * ( instaTemp / targetTemp - 1.0) / tt2;
143    
144 gezelter 772 // calculate the integral of chidt
145 tim 767 integralOfChidt += dt2*chi;
146    
147 gezelter 772 // advance eta half step
148    
149 tim 767 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 gezelter 772 eta[i][j] += dt2 * instaVol * press[i][j] / (NkBT*tb2);
156 tim 767 }
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 gezelter 600
165 tim 767 //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 gezelter 772 if (nConstrained) {
187     constrainA();
188     }
189 tim 767 }
190    
191    
192 gezelter 577 // Scale the box after all the positions have been moved:
193 gezelter 600
194 gezelter 578 // Use a taylor expansion for eta products: Hmat = Hmat . exp(dt * etaMat)
195     // Hmat = Hmat . ( Ident + dt * etaMat + dt^2 * etaMat*etaMat / 2)
196 gezelter 600
197 gezelter 617 bigScale = 1.0;
198     smallScale = 1.0;
199     offDiagMax = 0.0;
200 gezelter 600
201 gezelter 578 for(i=0; i<3; i++){
202     for(j=0; j<3; j++){
203 gezelter 600
204 gezelter 588 // Calculate the matrix Product of the eta array (we only need
205     // the ij element right now):
206 gezelter 600
207 gezelter 588 eta2ij = 0.0;
208 gezelter 578 for(k=0; k<3; k++){
209 gezelter 588 eta2ij += eta[i][k] * eta[k][j];
210 gezelter 578 }
211 gezelter 588
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 gezelter 617
218     if (i != j)
219     if (fabs(scaleMat[i][j]) > offDiagMax)
220     offDiagMax = fabs(scaleMat[i][j]);
221 gezelter 578 }
222 gezelter 617
223     if (scaleMat[i][i] > bigScale) bigScale = scaleMat[i][i];
224     if (scaleMat[i][i] < smallScale) smallScale = scaleMat[i][i];
225 gezelter 578 }
226 gezelter 600
227 gezelter 617 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 gezelter 577
257 gezelter 576 }
258    
259 tim 645 template<typename T> void NPTf<T>::moveB( void ){
260 gezelter 600
261 gezelter 772 //new version of NPTf
262 tim 767 int i, j, k;
263 gezelter 576 DirectionalAtom* dAtom;
264 gezelter 600 double Tb[3], ji[3];
265 gezelter 772 double vel[3], myVel[3], frc[3];
266 gezelter 600 double mass;
267    
268     double instaTemp, instaPress, instaVol;
269 gezelter 576 double tt2, tb2;
270 gezelter 600 double sc[3];
271 gezelter 588 double press[3][3], vScale[3][3];
272 tim 767 double oldChi, prevChi;
273 gezelter 772 double oldEta[3][3], prevEta[3][3], diffEta;
274 gezelter 576
275     tt2 = tauThermostat * tauThermostat;
276     tb2 = tauBarostat * tauBarostat;
277    
278 tim 767 // Set things up for the iteration:
279    
280     oldChi = chi;
281 gezelter 578
282 tim 767 for(i = 0; i < 3; i++)
283     for(j = 0; j < 3; j++)
284     oldEta[i][j] = eta[i][j];
285 gezelter 578
286 tim 767 for( i=0; i<nAtoms; i++ ){
287 gezelter 588
288 tim 767 atoms[i]->getVel( vel );
289 gezelter 588
290 tim 767 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 gezelter 588 }
303     }
304    
305 tim 767 // do the iteration:
306 gezelter 578
307 tim 767 instaVol = tStats->getVolume();
308    
309     for (k=0; k < 4; k++) {
310 gezelter 600
311 tim 767 instaTemp = tStats->getTemperature();
312     tStats->getPressureTensor(press);
313 gezelter 578
314 tim 767 // 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 gezelter 578
319 tim 767 for(i = 0; i < 3; i++)
320     for(j = 0; j < 3; j++)
321 gezelter 772 prevEta[i][j] = eta[i][j];
322 gezelter 600
323 tim 767 //advance eta half step and calculate scale factor for velocity
324 gezelter 772
325 tim 767 for(i = 0; i < 3; i ++)
326     for(j = 0; j < 3; j++){
327 gezelter 772 if( i == j) {
328 tim 767 eta[i][j] = oldEta[i][j] + dt2 * instaVol *
329 gezelter 772 (press[i][j] - targetPressure/p_convert) / (NkBT*tb2);
330 tim 767 vScale[i][j] = eta[i][j] + chi;
331 gezelter 772 } else {
332 tim 767 eta[i][j] = oldEta[i][j] + dt2 * instaVol * press[i][j] / (NkBT*tb2);
333     vScale[i][j] = eta[i][j];
334     }
335 gezelter 772 }
336    
337 tim 767 for( i=0; i<nAtoms; i++ ){
338    
339     atoms[i]->getFrc( frc );
340     atoms[i]->getVel(vel);
341 gezelter 576
342 tim 767 mass = atoms[i]->getMass();
343 gezelter 772
344     for (j = 0; j < 3; j++)
345     myVel[j] = oldVel[3*i + j];
346 gezelter 576
347 gezelter 772 info->matVecMul3( vScale, myVel, sc );
348    
349     // velocity half step
350 tim 767 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 gezelter 576
355 tim 767 atoms[i]->setVel( vel );
356 gezelter 576
357 tim 767 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 gezelter 576
369 tim 767 dAtom->setJ( ji );
370     }
371     }
372 gezelter 600
373 gezelter 772 if (nConstrained) {
374     constrainB();
375     }
376 tim 767
377     diffEta = 0;
378     for(i = 0; i < 3; i++)
379 gezelter 772 diffEta += pow(prevEta[i][i] - eta[i][i], 2);
380 tim 767
381     if (fabs(prevChi - chi) <= chiTolerance && sqrt(diffEta / 3) <= etaTolerance)
382     break;
383 gezelter 576 }
384 tim 767
385 gezelter 772 //calculate integral of chidt
386 tim 767 integralOfChidt += dt2*chi;
387    
388 gezelter 576 }
389    
390 mmeineke 746 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 tim 645 template<typename T> int NPTf<T>::readyCheck() {
402 tim 658
403     //check parent's readyCheck() first
404     if (T::readyCheck() == -1)
405     return -1;
406 gezelter 576
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 gezelter 580 "NPTf error: You can't use the NPTf integrator\n"
413 gezelter 576 " 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 gezelter 580 "NPTf error: You can't use the NPTf integrator\n"
423 gezelter 576 " 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 gezelter 580 "NPTf error: If you use the NPTf\n"
435 gezelter 576 " 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 gezelter 580 "NPTf error: If you use the NPTf\n"
446 gezelter 576 " integrator, you must set tauBarostat.\n");
447     painCave.isFatal = 1;
448     simError();
449     return -1;
450     }
451    
452 gezelter 772
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 tim 767 NkBT = (double)Nparticles * kB * targetTemp;
458 gezelter 772
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 tim 767 fkBT = (double)info->ndf * kB * targetTemp;
464 gezelter 576
465     return 1;
466     }
467 tim 763
468     template<typename T> double NPTf<T>::getConservedQuantity(void){
469    
470     double conservedQuantity;
471 gezelter 772 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 tim 763
479 gezelter 772 Energy = tStats->getTotalE();
480 tim 763
481 gezelter 772 thermostat_kinetic = fkBT* tauThermostat * tauThermostat * chi * chi /
482     (2.0 * eConvert);
483 tim 763
484 gezelter 772 thermostat_potential = fkBT* integralOfChidt / eConvert;
485 tim 763
486 gezelter 772 info->transposeMat3(eta, a);
487     info->matMul3(a, eta, b);
488     trEta = info->matTrace3(b);
489 tim 767
490 gezelter 772 barostat_kinetic = NkBT * tauBarostat * tauBarostat * trEta /
491     (2.0 * eConvert);
492    
493     barostat_potential = (targetPressure * tStats->getVolume() / p_convert) /
494     eConvert;
495 tim 767
496 gezelter 772 conservedQuantity = Energy + thermostat_kinetic + thermostat_potential +
497     barostat_kinetic + barostat_potential;
498    
499 tim 767 cout.width(8);
500     cout.precision(8);
501    
502 gezelter 772 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 tim 763 }