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root/group/trunk/OOPSE/libmdtools/NPTi.cpp
Revision: 767
Committed: Tue Sep 16 20:02:11 2003 UTC (20 years, 9 months ago) by tim
File size: 9539 byte(s)
Log Message:
fixed ecr grow in SimInfo

fixed conserved quantity in NPT (Still some small bug)

NPTi appears very stable.

File Contents

# User Rev Content
1 gezelter 578 #include <cmath>
2 gezelter 574 #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 tim 763 #ifdef IS_MPI
13     #include "mpiSimulation.hpp"
14     #endif
15 gezelter 574
16 tim 763
17 gezelter 574 // Basic isotropic thermostating and barostating via the Melchionna
18     // modification of the Hoover algorithm:
19     //
20     // Melchionna, S., Ciccotti, G., and Holian, B. L., 1993,
21     // Molec. Phys., 78, 533.
22     //
23     // and
24     //
25     // Hoover, W. G., 1986, Phys. Rev. A, 34, 2499.
26    
27 tim 645 template<typename T> NPTi<T>::NPTi ( SimInfo *theInfo, ForceFields* the_ff):
28     T( theInfo, the_ff )
29 gezelter 574 {
30     chi = 0.0;
31     eta = 0.0;
32 tim 763 integralOfChidt = 0.0;
33 gezelter 574 have_tau_thermostat = 0;
34     have_tau_barostat = 0;
35     have_target_temp = 0;
36     have_target_pressure = 0;
37 tim 763 have_chi_tolerance = 0;
38     have_eta_tolerance = 0;
39     have_pos_iter_tolerance = 0;
40    
41     oldPos = new double[3*nAtoms];
42     oldVel = new double[3*nAtoms];
43     oldJi = new double[3*nAtoms];
44     #ifdef IS_MPI
45     Nparticles = mpiSim->getTotAtoms();
46     #else
47     Nparticles = theInfo->n_atoms;
48     #endif
49    
50 gezelter 574 }
51    
52 tim 763 template<typename T> NPTi<T>::~NPTi() {
53     delete[] oldPos;
54     delete[] oldVel;
55     delete[] oldJi;
56     }
57    
58 tim 645 template<typename T> void NPTi<T>::moveA() {
59 tim 763
60     //new version of NPTi
61     int i, j, k;
62 gezelter 574 DirectionalAtom* dAtom;
63 gezelter 600 double Tb[3], ji[3];
64     double A[3][3], I[3][3];
65     double angle, mass;
66     double vel[3], pos[3], frc[3];
67    
68 gezelter 574 double rj[3];
69     double instaTemp, instaPress, instaVol;
70 gezelter 611 double tt2, tb2, scaleFactor;
71 tim 763 double COM[3];
72 gezelter 574
73     tt2 = tauThermostat * tauThermostat;
74     tb2 = tauBarostat * tauBarostat;
75    
76     instaTemp = tStats->getTemperature();
77     instaPress = tStats->getPressure();
78     instaVol = tStats->getVolume();
79    
80 tim 763 tStats->getCOM(COM);
81    
82     //evolve velocity half step
83     for( i=0; i<nAtoms; i++ ){
84 gezelter 574
85 gezelter 600 atoms[i]->getVel( vel );
86     atoms[i]->getFrc( frc );
87 gezelter 574
88 gezelter 600 mass = atoms[i]->getMass();
89 gezelter 574
90 gezelter 600 for (j=0; j < 3; j++) {
91 tim 763 // velocity half step (use chi from previous step here):
92     vel[j] += dt2 * ((frc[j] / mass ) * eConvert - vel[j]*(chi + eta));
93    
94 gezelter 600 }
95    
96     atoms[i]->setVel( vel );
97 tim 763
98 gezelter 574 if( atoms[i]->isDirectional() ){
99    
100     dAtom = (DirectionalAtom *)atoms[i];
101 tim 763
102 gezelter 574 // get and convert the torque to body frame
103    
104 gezelter 600 dAtom->getTrq( Tb );
105 gezelter 574 dAtom->lab2Body( Tb );
106    
107     // get the angular momentum, and propagate a half step
108    
109 gezelter 600 dAtom->getJ( ji );
110    
111     for (j=0; j < 3; j++)
112     ji[j] += dt2 * (Tb[j] * eConvert - ji[j]*chi);
113 gezelter 574
114     // use the angular velocities to propagate the rotation matrix a
115     // full time step
116 gezelter 600
117     dAtom->getA(A);
118     dAtom->getI(I);
119    
120 gezelter 574 // rotate about the x-axis
121 gezelter 600 angle = dt2 * ji[0] / I[0][0];
122     this->rotate( 1, 2, angle, ji, A );
123    
124 gezelter 574 // rotate about the y-axis
125 gezelter 600 angle = dt2 * ji[1] / I[1][1];
126     this->rotate( 2, 0, angle, ji, A );
127 gezelter 574
128     // rotate about the z-axis
129 gezelter 600 angle = dt * ji[2] / I[2][2];
130     this->rotate( 0, 1, angle, ji, A);
131 gezelter 574
132     // rotate about the y-axis
133 gezelter 600 angle = dt2 * ji[1] / I[1][1];
134     this->rotate( 2, 0, angle, ji, A );
135 gezelter 574
136     // rotate about the x-axis
137 gezelter 600 angle = dt2 * ji[0] / I[0][0];
138     this->rotate( 1, 2, angle, ji, A );
139 gezelter 574
140 gezelter 600 dAtom->setJ( ji );
141     dAtom->setA( A );
142 tim 763 }
143     }
144 gezelter 600
145 tim 763 // evolve chi and eta half step
146    
147     chi += dt2 * ( instaTemp / targetTemp - 1.0) / tt2;
148     eta += dt2 * ( instaVol * (instaPress - targetPressure) / (p_convert*NkBT*tb2));
149    
150     //calculate the integral of chidt
151     integralOfChidt += dt2*chi;
152    
153     //save the old positions
154     for(i = 0; i < nAtoms; i++){
155     atoms[i]->getPos(pos);
156     for(j = 0; j < 3; j++)
157     oldPos[i*3 + j] = pos[j];
158 gezelter 574 }
159 tim 763
160     //the first estimation of r(t+dt) is equal to r(t)
161    
162     for(k = 0; k < 4; k ++){
163 gezelter 611
164 tim 763 for(i =0 ; i < nAtoms; i++){
165    
166     atoms[i]->getVel(vel);
167     atoms[i]->getPos(pos);
168    
169     for(j = 0; j < 3; j++)
170 tim 767 rj[j] = (oldPos[i*3 + j] + pos[j])/2 - COM[j];
171 tim 763
172     for(j = 0; j < 3; j++)
173     pos[j] = oldPos[i*3 + j] + dt*(vel[j] + eta*rj[j]);
174    
175     atoms[i]->setPos( pos );
176    
177     }
178    
179     }
180    
181    
182 gezelter 577 // Scale the box after all the positions have been moved:
183 gezelter 600
184 gezelter 611 scaleFactor = exp(dt*eta);
185    
186 mmeineke 614 if ((scaleFactor > 1.1) || (scaleFactor < 0.9)) {
187 gezelter 611 sprintf( painCave.errMsg,
188     "NPTi error: Attempting a Box scaling of more than 10 percent"
189     " check your tauBarostat, as it is probably too small!\n"
190     " eta = %lf, scaleFactor = %lf\n", eta, scaleFactor
191     );
192     painCave.isFatal = 1;
193     simError();
194     } else {
195 tim 763 info->scaleBox(scaleFactor);
196     }
197 mmeineke 614
198 gezelter 574 }
199    
200 tim 645 template<typename T> void NPTi<T>::moveB( void ){
201 gezelter 574
202 tim 763 //new version of NPTi
203     int i, j, k;
204     DirectionalAtom* dAtom;
205     double Tb[3], ji[3];
206     double vel[3], frc[3];
207     double mass;
208    
209     double instTemp, instPress, instVol;
210     double tt2, tb2;
211     double oldChi, prevChi;
212     double oldEta, preEta;
213    
214     tt2 = tauThermostat * tauThermostat;
215     tb2 = tauBarostat * tauBarostat;
216    
217    
218     // Set things up for the iteration:
219    
220     oldChi = chi;
221     oldEta = eta;
222    
223     for( i=0; i<nAtoms; i++ ){
224    
225     atoms[i]->getVel( vel );
226    
227     for (j=0; j < 3; j++)
228     oldVel[3*i + j] = vel[j];
229    
230     if( atoms[i]->isDirectional() ){
231    
232     dAtom = (DirectionalAtom *)atoms[i];
233    
234     dAtom->getJ( ji );
235    
236     for (j=0; j < 3; j++)
237     oldJi[3*i + j] = ji[j];
238    
239     }
240     }
241    
242     // do the iteration:
243    
244     instVol = tStats->getVolume();
245    
246     for (k=0; k < 4; k++) {
247    
248     instTemp = tStats->getTemperature();
249     instPress = tStats->getPressure();
250    
251     // evolve chi another half step using the temperature at t + dt/2
252    
253     prevChi = chi;
254     chi = oldChi + dt2 * ( instTemp / targetTemp - 1.0) /
255     (tauThermostat*tauThermostat);
256    
257     preEta = eta;
258     eta = oldEta + dt2 * ( instVol * (instPress - targetPressure) /
259     (p_convert*NkBT*tb2));
260    
261    
262     for( i=0; i<nAtoms; i++ ){
263    
264     atoms[i]->getFrc( frc );
265     atoms[i]->getVel(vel);
266    
267     mass = atoms[i]->getMass();
268    
269     // velocity half step
270     for (j=0; j < 3; j++)
271     vel[j] = oldVel[3*i+j] + dt2 * ((frc[j] / mass ) * eConvert - oldVel[3*i + j]*(chi + eta));
272    
273     atoms[i]->setVel( vel );
274    
275     if( atoms[i]->isDirectional() ){
276    
277     dAtom = (DirectionalAtom *)atoms[i];
278    
279     // get and convert the torque to body frame
280    
281     dAtom->getTrq( Tb );
282     dAtom->lab2Body( Tb );
283    
284     for (j=0; j < 3; j++)
285     ji[j] = oldJi[3*i + j] + dt2 * (Tb[j] * eConvert - oldJi[3*i+j]*chi);
286    
287     dAtom->setJ( ji );
288     }
289     }
290    
291     if (fabs(prevChi - chi) <= chiTolerance && fabs(preEta -eta) <= etaTolerance)
292     break;
293     }
294    
295     //calculate integral of chida
296     integralOfChidt += dt2*chi;
297    
298    
299 gezelter 574 }
300    
301 mmeineke 746 template<typename T> void NPTi<T>::resetIntegrator() {
302     chi = 0.0;
303     eta = 0.0;
304     }
305    
306 tim 645 template<typename T> int NPTi<T>::readyCheck() {
307 tim 658
308     //check parent's readyCheck() first
309     if (T::readyCheck() == -1)
310     return -1;
311 gezelter 574
312     // First check to see if we have a target temperature.
313     // Not having one is fatal.
314    
315     if (!have_target_temp) {
316     sprintf( painCave.errMsg,
317     "NPTi error: You can't use the NPTi integrator\n"
318     " without a targetTemp!\n"
319     );
320     painCave.isFatal = 1;
321     simError();
322     return -1;
323     }
324    
325     if (!have_target_pressure) {
326     sprintf( painCave.errMsg,
327     "NPTi error: You can't use the NPTi integrator\n"
328     " without a targetPressure!\n"
329     );
330     painCave.isFatal = 1;
331     simError();
332     return -1;
333     }
334    
335     // We must set tauThermostat.
336    
337     if (!have_tau_thermostat) {
338     sprintf( painCave.errMsg,
339     "NPTi error: If you use the NPTi\n"
340     " integrator, you must set tauThermostat.\n");
341     painCave.isFatal = 1;
342     simError();
343     return -1;
344     }
345    
346     // We must set tauBarostat.
347    
348     if (!have_tau_barostat) {
349     sprintf( painCave.errMsg,
350     "NPTi error: If you use the NPTi\n"
351     " integrator, you must set tauBarostat.\n");
352     painCave.isFatal = 1;
353     simError();
354     return -1;
355     }
356    
357 tim 763 if (!have_chi_tolerance) {
358     sprintf( painCave.errMsg,
359     "NPTi warning: setting chi tolerance to 1e-6\n");
360     chiTolerance = 1e-6;
361     have_chi_tolerance = 1;
362     painCave.isFatal = 0;
363     simError();
364     }
365    
366     if (!have_eta_tolerance) {
367     sprintf( painCave.errMsg,
368     "NPTi warning: setting eta tolerance to 1e-6\n");
369     etaTolerance = 1e-6;
370     have_eta_tolerance = 1;
371     painCave.isFatal = 0;
372     simError();
373     }
374 gezelter 574 // We need NkBT a lot, so just set it here:
375    
376 tim 763 NkBT = (double)Nparticles * kB * targetTemp;
377     fkBT = (double)info->ndf * kB * targetTemp;
378 gezelter 574
379     return 1;
380     }
381 tim 763
382     template<typename T> double NPTi<T>::getConservedQuantity(void){
383    
384     double conservedQuantity;
385     double tb2;
386     double eta2;
387     double E_NPT;
388     double U;
389     double TS;
390     double PV;
391     double extra;
392    
393     U = tStats->getTotalE();
394    
395     TS = fkBT *
396     (integralOfChidt + tauThermostat * tauThermostat * chi * chi / 2.0) / eConvert;
397    
398     PV = (targetPressure * tStats->getVolume() / p_convert) / eConvert;
399    
400     tb2 = tauBarostat * tauBarostat;
401     eta2 = eta * eta;
402    
403    
404 tim 767 extra = ((double)info->ndfTrans * kB * targetTemp * tb2 * eta2 / 2.0) / eConvert;
405    
406 tim 763 cout.width(8);
407     cout.precision(8);
408    
409    
410     cout << info->getTime() << "\t"
411     << chi << "\t"
412     << eta << "\t"
413     << U << "\t"
414     << TS << "\t"
415     << PV << "\t"
416     << extra << "\t"
417     << U+TS+PV+extra << endl;
418    
419     conservedQuantity = U+TS+PV+extra;
420     return conservedQuantity;
421     }