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root/OpenMD/trunk/src/integrators/NPA.cpp
Revision: 2011
Committed: Wed Aug 6 19:27:37 2014 UTC (10 years, 8 months ago) by gezelter
File size: 10229 byte(s)
Log Message:
Added NPA integrator

File Contents

# Content
1 /*
2 * Copyright (c) 2005 The University of Notre Dame. All Rights Reserved.
3 *
4 * The University of Notre Dame grants you ("Licensee") a
5 * non-exclusive, royalty free, license to use, modify and
6 * redistribute this software in source and binary code form, provided
7 * that the following conditions are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the
15 * distribution.
16 *
17 * This software is provided "AS IS," without a warranty of any
18 * kind. All express or implied conditions, representations and
19 * warranties, including any implied warranty of merchantability,
20 * fitness for a particular purpose or non-infringement, are hereby
21 * excluded. The University of Notre Dame and its licensors shall not
22 * be liable for any damages suffered by licensee as a result of
23 * using, modifying or distributing the software or its
24 * derivatives. In no event will the University of Notre Dame or its
25 * licensors be liable for any lost revenue, profit or data, or for
26 * direct, indirect, special, consequential, incidental or punitive
27 * damages, however caused and regardless of the theory of liability,
28 * arising out of the use of or inability to use software, even if the
29 * University of Notre Dame has been advised of the possibility of
30 * such damages.
31 *
32 * SUPPORT OPEN SCIENCE! If you use OpenMD or its source code in your
33 * research, please cite the appropriate papers when you publish your
34 * work. Good starting points are:
35 *
36 * [1] Meineke, et al., J. Comp. Chem. 26, 252-271 (2005).
37 * [2] Fennell & Gezelter, J. Chem. Phys. 124, 234104 (2006).
38 * [3] Sun, Lin & Gezelter, J. Chem. Phys. 128, 234107 (2008).
39 * [4] Kuang & Gezelter, J. Chem. Phys. 133, 164101 (2010).
40 * [5] Vardeman, Stocker & Gezelter, J. Chem. Theory Comput. 7, 834 (2011).
41 */
42
43 #include "brains/SimInfo.hpp"
44 #include "brains/Thermo.hpp"
45 #include "integrators/IntegratorCreator.hpp"
46 #include "integrators/NPA.hpp"
47 #include "primitives/Molecule.hpp"
48 #include "utils/PhysicalConstants.hpp"
49 #include "utils/simError.h"
50
51 namespace OpenMD {
52
53 void NPA::moveA() {
54 SimInfo::MoleculeIterator i;
55 Molecule::IntegrableObjectIterator j;
56 Molecule* mol;
57 StuntDouble* sd;
58 Vector3d Tb, ji;
59 RealType mass;
60 Vector3d vel;
61 Vector3d pos;
62 Vector3d frc;
63 Vector3d sc;
64 int index;
65
66 loadEta();
67
68 instaTemp =thermo.getTemperature();
69 press = thermo.getPressureTensor();
70 instaPress = PhysicalConstants::pressureConvert* (press(0, 0) +
71 press(1, 1) +
72 press(2, 2)) / 3.0;
73 instaVol =thermo.getVolume();
74
75 Vector3d COM = thermo.getCom();
76
77 //evolve velocity half step
78
79 calcVelScale();
80
81 for (mol = info_->beginMolecule(i); mol != NULL;
82 mol = info_->nextMolecule(i)) {
83
84 for (sd = mol->beginIntegrableObject(j); sd != NULL;
85 sd = mol->nextIntegrableObject(j)) {
86
87 vel = sd->getVel();
88 frc = sd->getFrc();
89
90 mass = sd->getMass();
91
92 getVelScaleA(sc, vel);
93
94 // velocity half step (use chi from previous step here):
95
96 vel += dt2*PhysicalConstants::energyConvert/mass* frc - dt2*sc;
97 sd->setVel(vel);
98
99 if (sd->isDirectional()) {
100
101 // get and convert the torque to body frame
102
103 Tb = sd->lab2Body(sd->getTrq());
104
105 // get the angular momentum, and propagate a half step
106
107 ji = sd->getJ();
108
109 ji += dt2*PhysicalConstants::energyConvert * Tb
110 - dt2*thermostat.first* ji;
111
112 rotAlgo_->rotate(sd, ji, dt);
113
114 sd->setJ(ji);
115 }
116 }
117 }
118 // evolve eta a half step
119
120 evolveEtaA();
121 flucQ_->moveA();
122
123 index = 0;
124 for (mol = info_->beginMolecule(i); mol != NULL;
125 mol = info_->nextMolecule(i)) {
126
127 for (sd = mol->beginIntegrableObject(j); sd != NULL;
128 sd = mol->nextIntegrableObject(j)) {
129
130 oldPos[index++] = sd->getPos();
131
132 }
133 }
134
135 //the first estimation of r(t+dt) is equal to r(t)
136
137 for(int k = 0; k < maxIterNum_; k++) {
138 index = 0;
139 for (mol = info_->beginMolecule(i); mol != NULL;
140 mol = info_->nextMolecule(i)) {
141
142 for (sd = mol->beginIntegrableObject(j); sd != NULL;
143 sd = mol->nextIntegrableObject(j)) {
144
145 vel = sd->getVel();
146 pos = sd->getPos();
147
148 this->getPosScale(pos, COM, index, sc);
149
150 pos = oldPos[index] + dt * (vel + sc);
151 sd->setPos(pos);
152
153 ++index;
154 }
155 }
156
157 rattle_->constraintA();
158 }
159
160 // Scale the box after all the positions have been moved:
161
162 this->scaleSimBox();
163
164 saveEta();
165 }
166
167 void NPA::moveB(void) {
168 SimInfo::MoleculeIterator i;
169 Molecule::IntegrableObjectIterator j;
170 Molecule* mol;
171 StuntDouble* sd;
172 int index;
173 Vector3d Tb;
174 Vector3d ji;
175 Vector3d sc;
176 Vector3d vel;
177 Vector3d frc;
178 RealType mass;
179
180 loadEta();
181
182 //save velocity and angular momentum
183 index = 0;
184 for (mol = info_->beginMolecule(i); mol != NULL;
185 mol = info_->nextMolecule(i)) {
186
187 for (sd = mol->beginIntegrableObject(j); sd != NULL;
188 sd = mol->nextIntegrableObject(j)) {
189
190 oldVel[index] = sd->getVel();
191
192 if (sd->isDirectional())
193 oldJi[index] = sd->getJ();
194
195 ++index;
196 }
197 }
198
199 instaVol = thermo.getVolume();
200 instaTemp = thermo.getTemperature();
201 instaPress = thermo.getPressure();
202
203 //evolve eta
204 this->evolveEtaB();
205 this->calcVelScale();
206
207 index = 0;
208 for (mol = info_->beginMolecule(i); mol != NULL;
209 mol = info_->nextMolecule(i)) {
210
211 for (sd = mol->beginIntegrableObject(j); sd != NULL;
212 sd = mol->nextIntegrableObject(j)) {
213
214 frc = sd->getFrc();
215 mass = sd->getMass();
216
217 getVelScaleB(sc, index);
218
219 // velocity half step
220 vel = oldVel[index]
221 + dt2*PhysicalConstants::energyConvert/mass* frc
222 - dt2*sc;
223
224 sd->setVel(vel);
225
226 if (sd->isDirectional()) {
227 // get and convert the torque to body frame
228 Tb = sd->lab2Body(sd->getTrq());
229
230 ji = oldJi[index]
231 + dt2*PhysicalConstants::energyConvert*Tb
232 - dt2*thermostat.first*oldJi[index];
233
234 sd->setJ(ji);
235 }
236
237 ++index;
238 }
239 }
240
241 rattle_->constraintB();
242
243 flucQ_->moveB();
244 saveEta();
245 }
246
247 void NPA::evolveEtaA() {
248
249 eta(2,2) += dt2 * instaVol * (press(2, 2) - targetPressure/PhysicalConstants::pressureConvert) / (NkBT*tb2);
250 oldEta = eta;
251 }
252
253 void NPA::evolveEtaB() {
254
255 prevEta = eta;
256 eta(2,2) = oldEta(2, 2) + dt2 * instaVol *
257 (press(2, 2) - targetPressure/PhysicalConstants::pressureConvert) / (NkBT*tb2);
258 }
259
260 void NPA::calcVelScale(){
261
262 for (int i = 0; i < 3; i++ ) {
263 for (int j = 0; j < 3; j++ ) {
264 vScale(i, j) = eta(i, j);
265 }
266 }
267 }
268
269 void NPA::getVelScaleA(Vector3d& sc, const Vector3d& vel){
270 sc = vScale * vel;
271 }
272
273 void NPA::getVelScaleB(Vector3d& sc, int index ) {
274 sc = vScale * oldVel[index];
275 }
276
277 void NPA::getPosScale(const Vector3d& pos, const Vector3d& COM, int index,
278 Vector3d& sc) {
279
280 Vector3d rj = (oldPos[index] + pos)/(RealType)2.0 -COM;
281 sc = eta * rj;
282 }
283
284 void NPA::scaleSimBox(){
285 Mat3x3d scaleMat;
286
287 for(int i=0; i<3; i++){
288 for(int j=0; j<3; j++){
289 scaleMat(i, j) = 0.0;
290 if(i==j) {
291 scaleMat(i, j) = 1.0;
292 }
293 }
294 }
295
296 scaleMat(2, 2) = exp(dt*eta(2, 2));
297 Mat3x3d hmat = snap->getHmat();
298 hmat = hmat *scaleMat;
299 snap->setHmat(hmat);
300 }
301
302 bool NPA::etaConverged() {
303 int i;
304 RealType diffEta, sumEta;
305
306 sumEta = 0;
307 for(i = 0; i < 3; i++) {
308 sumEta += pow(prevEta(i, i) - eta(i, i), 2);
309 }
310
311 diffEta = sqrt( sumEta / 3.0 );
312
313 return ( diffEta <= etaTolerance );
314 }
315
316 RealType NPA::calcConservedQuantity(){
317
318 thermostat = snap->getThermostat();
319 loadEta();
320
321 // We need NkBT a lot, so just set it here: This is the RAW number
322 // of integrableObjects, so no subtraction or addition of constraints or
323 // orientational degrees of freedom:
324 NkBT = info_->getNGlobalIntegrableObjects()*PhysicalConstants::kB *targetTemp;
325
326 // fkBT is used because the thermostat operates on more degrees of freedom
327 // than the barostat (when there are particles with orientational degrees
328 // of freedom).
329 fkBT = info_->getNdf()*PhysicalConstants::kB *targetTemp;
330
331 RealType conservedQuantity;
332 RealType totalEnergy;
333 RealType thermostat_kinetic;
334 RealType thermostat_potential;
335 RealType barostat_kinetic;
336 RealType barostat_potential;
337 RealType trEta;
338
339 totalEnergy = thermo.getTotalEnergy();
340
341 thermostat_kinetic = 0.0;
342 thermostat_potential = 0.0;
343
344 SquareMatrix<RealType, 3> tmp = eta.transpose() * eta;
345 trEta = tmp.trace();
346
347 barostat_kinetic = NkBT * tb2 * trEta /(2.0 * PhysicalConstants::energyConvert);
348
349 barostat_potential = (targetPressure * thermo.getVolume() / PhysicalConstants::pressureConvert) /PhysicalConstants::energyConvert;
350
351 conservedQuantity = totalEnergy + thermostat_kinetic + thermostat_potential +
352 barostat_kinetic + barostat_potential;
353
354 return conservedQuantity;
355
356 }
357
358 void NPA::loadEta() {
359 eta= snap->getBarostat();
360
361 //if (!eta.isDiagonal()) {
362 // sprintf( painCave.errMsg,
363 // "NPA error: the diagonal elements of eta matrix are not the same or etaMat is not a diagonal matrix");
364 // painCave.isFatal = 1;
365 // simError();
366 //}
367 }
368
369 void NPA::saveEta() {
370 snap->setBarostat(eta);
371 }
372
373 }
374

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