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root/group/branches/new-templateless/OOPSE/libmdtools/NPT.cpp
Revision: 852
Committed: Thu Nov 6 18:20:47 2003 UTC (20 years, 9 months ago) by mmeineke
File size: 7804 byte(s)
Log Message:
fixed the "Sudden Death" bug.
	The box was not switching between orthorhombic and non-orthorhombic wrapping correctly.
	we added a fabs() to the check.which should fix it.

File Contents

# Content
1 #include <stdlib.h>
2 #include <math.h>
3
4 #include "Atom.hpp"
5 #include "SRI.hpp"
6 #include "AbstractClasses.hpp"
7 #include "SimInfo.hpp"
8 #include "ForceFields.hpp"
9 #include "Thermo.hpp"
10 #include "ReadWrite.hpp"
11 #include "Integrator.hpp"
12 #include "simError.h"
13
14 #ifdef IS_MPI
15 #include "mpiSimulation.hpp"
16 #endif
17
18
19 // Basic isotropic thermostating and barostating via the Melchionna
20 // modification of the Hoover algorithm:
21 //
22 // Melchionna, S., Ciccotti, G., and Holian, B. L., 1993,
23 // Molec. Phys., 78, 533.
24 //
25 // and
26 //
27 // Hoover, W. G., 1986, Phys. Rev. A, 34, 2499.
28
29 NPT::NPT ( SimInfo *theInfo, ForceFields* the_ff):
30 Integrator( theInfo, the_ff )
31 {
32 GenericData* data;
33
34 chi = 0.0;
35 integralOfChidt = 0.0;
36 have_tau_thermostat = 0;
37 have_tau_barostat = 0;
38 have_target_temp = 0;
39 have_target_pressure = 0;
40 have_chi_tolerance = 0;
41 have_eta_tolerance = 0;
42 have_pos_iter_tolerance = 0;
43
44 // retrieve chi and integralOfChidt from simInfo
45 data = info->getProperty(CHIVALUE_ID);
46 if(data != NULL ){
47 chi = data->getDval();
48 }
49
50 data = info->getProperty(INTEGRALOFCHIDT_ID);
51 if(data != NULL ){
52 integralOfChidt = data->getDval();
53 }
54
55 oldPos = new double[3*nAtoms];
56 oldVel = new double[3*nAtoms];
57 oldJi = new double[3*nAtoms];
58 #ifdef IS_MPI
59 Nparticles = mpiSim->getTotAtoms();
60 #else
61 Nparticles = theInfo->n_atoms;
62 #endif
63
64 }
65
66 NPT::~NPT() {
67 delete[] oldPos;
68 delete[] oldVel;
69 delete[] oldJi;
70 }
71
72 void NPT::moveA() {
73
74 //new version of NPT
75 int i, j, k;
76 DirectionalAtom* dAtom;
77 double Tb[3], ji[3];
78 double mass;
79 double vel[3], pos[3], frc[3];
80 double sc[3];
81 double COM[3];
82
83 instaTemp = tStats->getTemperature();
84
85 tStats->getPressureTensor( press );
86 instaPress = p_convert * (press[0][0] + press[1][1] + press[2][2]) / 3.0;
87
88 instaVol = tStats->getVolume();
89
90 tStats->getCOM(COM);
91
92 //evolve velocity half step
93 for( i=0; i<nAtoms; i++ ){
94
95 atoms[i]->getVel( vel );
96 atoms[i]->getFrc( frc );
97
98 mass = atoms[i]->getMass();
99
100 getVelScaleA( sc, vel );
101
102 for (j=0; j < 3; j++) {
103
104 // velocity half step (use chi from previous step here):
105 vel[j] += dt2 * ((frc[j] / mass ) * eConvert - sc[j]);
106
107 }
108
109 atoms[i]->setVel( vel );
110
111 if( atoms[i]->isDirectional() ){
112
113 dAtom = (DirectionalAtom *)atoms[i];
114
115 // get and convert the torque to body frame
116
117 dAtom->getTrq( Tb );
118 dAtom->lab2Body( Tb );
119
120 // get the angular momentum, and propagate a half step
121
122 dAtom->getJ( ji );
123
124 for (j=0; j < 3; j++)
125 ji[j] += dt2 * (Tb[j] * eConvert - ji[j]*chi);
126
127 this->rotationPropagation( dAtom, ji );
128
129 dAtom->setJ( ji );
130 }
131 }
132
133 // evolve chi and eta half step
134
135 evolveChiA();
136 evolveEtaA();
137
138 //calculate the integral of chidt
139 integralOfChidt += dt2*chi;
140
141 //save the old positions
142 for(i = 0; i < nAtoms; i++){
143 atoms[i]->getPos(pos);
144 for(j = 0; j < 3; j++)
145 oldPos[i*3 + j] = pos[j];
146 }
147
148 //the first estimation of r(t+dt) is equal to r(t)
149
150 for(k = 0; k < 5; k ++){
151
152 for(i =0 ; i < nAtoms; i++){
153
154 atoms[i]->getVel(vel);
155 atoms[i]->getPos(pos);
156
157 this->getPosScale( pos, COM, i, sc );
158
159 for(j = 0; j < 3; j++)
160 pos[j] = oldPos[i*3 + j] + dt*(vel[j] + sc[j]);
161
162 atoms[i]->setPos( pos );
163 }
164
165 if (nConstrained){
166 constrainA();
167 }
168 }
169
170
171 // Scale the box after all the positions have been moved:
172
173 this->scaleSimBox();
174 }
175
176 void NPT::moveB( void ){
177
178 //new version of NPT
179 int i, j, k;
180 DirectionalAtom* dAtom;
181 double Tb[3], ji[3], sc[3];
182 double vel[3], frc[3], qVel[3];
183 double mass;
184
185 // Set things up for the iteration:
186
187 for( i=0; i<nAtoms; i++ ){
188
189 atoms[i]->getVel( vel );
190
191 for (j=0; j < 3; j++)
192 oldVel[3*i + j] = vel[j];
193
194 if( atoms[i]->isDirectional() ){
195
196 dAtom = (DirectionalAtom *)atoms[i];
197
198 dAtom->getJ( ji );
199
200 for (j=0; j < 3; j++)
201 oldJi[3*i + j] = ji[j];
202
203 }
204 }
205
206 // do the iteration:
207
208 instaVol = tStats->getVolume();
209
210 for (k=0; k < 4; k++) {
211
212 atoms[0]->getVel(vel);
213
214 instaTemp = tStats->getTemperature();
215
216 instaPress = tStats->getPressure();
217
218 // evolve chi another half step using the temperature at t + dt/2
219
220 this->evolveChiB();
221 this->evolveEtaB();
222
223 for( i=0; i<nAtoms; i++ ){
224
225 atoms[i]->getFrc( frc );
226 atoms[i]->getVel(vel);
227
228 mass = atoms[i]->getMass();
229
230 getVelScaleB( sc, i );
231
232 for(j=0;j<3;j++)
233 qVel[j] = vel[j];
234
235 // velocity half step
236 for (j=0; j < 3; j++)
237 vel[j] = oldVel[3*i+j] + dt2 * ((frc[j] / mass ) * eConvert - sc[j]);
238
239 atoms[i]->setVel( vel );
240
241 if( atoms[i]->isDirectional() ){
242
243 dAtom = (DirectionalAtom *)atoms[i];
244
245 // get and convert the torque to body frame
246
247 dAtom->getTrq( Tb );
248 dAtom->lab2Body( Tb );
249
250 for (j=0; j < 3; j++)
251 ji[j] = oldJi[3*i + j] + dt2 * (Tb[j] * eConvert - oldJi[3*i+j]*chi);
252
253 dAtom->setJ( ji );
254 }
255 }
256
257 if (nConstrained){
258 constrainB();
259 }
260
261 if ( this->chiConverged() && this->etaConverged() ) break;
262 }
263
264 //calculate integral of chida
265 integralOfChidt += dt2*chi;
266
267
268 }
269
270 void NPT::resetIntegrator() {
271 chi = 0.0;
272 Integrator::resetIntegrator();
273 }
274
275 void NPT::evolveChiA() {
276
277 chi += dt2 * ( instaTemp / targetTemp - 1.0) / tt2;
278 oldChi = chi;
279 }
280
281 void NPT::evolveChiB() {
282
283 prevChi = chi;
284 chi = oldChi + dt2 * ( instaTemp / targetTemp - 1.0) / tt2;
285 }
286
287 bool NPT::chiConverged() {
288
289 return ( fabs( prevChi - chi ) <= chiTolerance );
290 }
291
292 int NPT::readyCheck() {
293
294 //check parent's readyCheck() first
295 if (Integrator::readyCheck() == -1)
296 return -1;
297
298 // First check to see if we have a target temperature.
299 // Not having one is fatal.
300
301 if (!have_target_temp) {
302 sprintf( painCave.errMsg,
303 "NPT error: You can't use the NPT integrator\n"
304 " without a targetTemp!\n"
305 );
306 painCave.isFatal = 1;
307 simError();
308 return -1;
309 }
310
311 if (!have_target_pressure) {
312 sprintf( painCave.errMsg,
313 "NPT error: You can't use the NPT integrator\n"
314 " without a targetPressure!\n"
315 );
316 painCave.isFatal = 1;
317 simError();
318 return -1;
319 }
320
321 // We must set tauThermostat.
322
323 if (!have_tau_thermostat) {
324 sprintf( painCave.errMsg,
325 "NPT error: If you use the NPT\n"
326 " integrator, you must set tauThermostat.\n");
327 painCave.isFatal = 1;
328 simError();
329 return -1;
330 }
331
332 // We must set tauBarostat.
333
334 if (!have_tau_barostat) {
335 sprintf( painCave.errMsg,
336 "NPT error: If you use the NPT\n"
337 " integrator, you must set tauBarostat.\n");
338 painCave.isFatal = 1;
339 simError();
340 return -1;
341 }
342
343 if (!have_chi_tolerance) {
344 sprintf( painCave.errMsg,
345 "NPT warning: setting chi tolerance to 1e-6\n");
346 chiTolerance = 1e-6;
347 have_chi_tolerance = 1;
348 painCave.isFatal = 0;
349 simError();
350 }
351
352 if (!have_eta_tolerance) {
353 sprintf( painCave.errMsg,
354 "NPT warning: setting eta tolerance to 1e-6\n");
355 etaTolerance = 1e-6;
356 have_eta_tolerance = 1;
357 painCave.isFatal = 0;
358 simError();
359 }
360
361 // We need NkBT a lot, so just set it here: This is the RAW number
362 // of particles, so no subtraction or addition of constraints or
363 // orientational degrees of freedom:
364
365 NkBT = (double)Nparticles * kB * targetTemp;
366
367 // fkBT is used because the thermostat operates on more degrees of freedom
368 // than the barostat (when there are particles with orientational degrees
369 // of freedom). ndf = 3 * (n_atoms + n_oriented -1) - n_constraint - nZcons
370
371 fkBT = (double)info->ndf * kB * targetTemp;
372
373 tt2 = tauThermostat * tauThermostat;
374 tb2 = tauBarostat * tauBarostat;
375
376 return 1;
377 }