| 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 "integrators/NVT.hpp" | 
| 44 | #include "primitives/Molecule.hpp" | 
| 45 | #include "utils/simError.h" | 
| 46 | #include "utils/PhysicalConstants.hpp" | 
| 47 |  | 
| 48 | namespace OpenMD { | 
| 49 |  | 
| 50 | NVT::NVT(SimInfo* info) : VelocityVerletIntegrator(info), chiTolerance_ (1e-6), maxIterNum_(4) { | 
| 51 |  | 
| 52 | Globals* simParams = info_->getSimParams(); | 
| 53 |  | 
| 54 | if (!simParams->getUseIntialExtendedSystemState()) { | 
| 55 | Snapshot* snap = info_->getSnapshotManager()->getCurrentSnapshot(); | 
| 56 | snap->setThermostat(make_pair(0.0, 0.0)); | 
| 57 | } | 
| 58 |  | 
| 59 | if (!simParams->haveTargetTemp()) { | 
| 60 | sprintf(painCave.errMsg, "You can't use the NVT integrator without a targetTemp_!\n"); | 
| 61 | painCave.isFatal = 1; | 
| 62 | painCave.severity = OPENMD_ERROR; | 
| 63 | simError(); | 
| 64 | } else { | 
| 65 | targetTemp_ = simParams->getTargetTemp(); | 
| 66 | } | 
| 67 |  | 
| 68 | // We must set tauThermostat. | 
| 69 |  | 
| 70 | if (!simParams->haveTauThermostat()) { | 
| 71 | sprintf(painCave.errMsg, "If you use the constant temperature\n" | 
| 72 | "\tintegrator, you must set tauThermostat.\n"); | 
| 73 |  | 
| 74 | painCave.severity = OPENMD_ERROR; | 
| 75 | painCave.isFatal = 1; | 
| 76 | simError(); | 
| 77 | } else { | 
| 78 | tauThermostat_ = simParams->getTauThermostat(); | 
| 79 | } | 
| 80 |  | 
| 81 | updateSizes(); | 
| 82 | } | 
| 83 |  | 
| 84 | void NVT::doUpdateSizes() { | 
| 85 | oldVel_.resize(info_->getNIntegrableObjects()); | 
| 86 | oldJi_.resize(info_->getNIntegrableObjects()); | 
| 87 | } | 
| 88 |  | 
| 89 | void NVT:evolveChiA(){ | 
| 90 | pair<RealType, RealType> thermostat = snap->getThermostat(); | 
| 91 | RealType instTemp = thermo.getTemperature(); | 
| 92 | thermostat.first += dt2 * (instTemp / targetTemp_ - 1.0) / (tauThermostat_ * tauThermostat_); | 
| 93 | thermostat.second += thermostat.first * dt2; | 
| 94 | snap->setThermostat(thermostat); | 
| 95 | oldChi_ = thermostat.first; | 
| 96 | oldChiInt_ = thermostat.second; | 
| 97 | } | 
| 98 |  | 
| 99 | void NVT::evolveChiB(){ | 
| 100 | pair<RealType, RealType> thermostat = snap->getThermostat(); | 
| 101 | RealType instTemp = thermo.getTemperature(); | 
| 102 | prevChi_ = thermostat.first; | 
| 103 | thermostat.first = oldChi_ + dt2 * (instTemp / targetTemp_ - 1.0) / (tauThermostat_ * tauThermostat_); | 
| 104 | thermostat.second = oldChiInt_ + dt2 * thermostat.first; | 
| 105 | snap->setThermostat(thermostat); | 
| 106 | } | 
| 107 |  | 
| 108 | void NVT::moveA() { | 
| 109 | SimInfo::MoleculeIterator i; | 
| 110 | Molecule::IntegrableObjectIterator  j; | 
| 111 | Molecule* mol; | 
| 112 | StuntDouble* sd; | 
| 113 | Vector3d Tb; | 
| 114 | Vector3d ji; | 
| 115 | RealType mass; | 
| 116 | Vector3d vel; | 
| 117 | Vector3d pos; | 
| 118 | Vector3d frc; | 
| 119 |  | 
| 120 | pair<RealType, RealType> thermostat = snap->getThermostat(); | 
| 121 |  | 
| 122 | // We need the temperature at time = t for the chi update below: | 
| 123 |  | 
| 124 | RealType instTemp = thermo.getTemperature(); | 
| 125 |  | 
| 126 | for (mol = info_->beginMolecule(i); mol != NULL; | 
| 127 | mol = info_->nextMolecule(i)) { | 
| 128 |  | 
| 129 | for (sd = mol->beginIntegrableObject(j); sd != NULL; | 
| 130 | sd = mol->nextIntegrableObject(j)) { | 
| 131 |  | 
| 132 | vel = sd->getVel(); | 
| 133 | pos = sd->getPos(); | 
| 134 | frc = sd->getFrc(); | 
| 135 |  | 
| 136 | mass = sd->getMass(); | 
| 137 |  | 
| 138 | // velocity half step (use chi from previous step here): | 
| 139 | vel += dt2 *PhysicalConstants::energyConvert/mass*frc | 
| 140 | - dt2*thermostat.first*vel; | 
| 141 |  | 
| 142 | // position whole step | 
| 143 | pos += dt * vel; | 
| 144 |  | 
| 145 | sd->setVel(vel); | 
| 146 | sd->setPos(pos); | 
| 147 |  | 
| 148 | if (sd->isDirectional()) { | 
| 149 |  | 
| 150 | //convert the torque to body frame | 
| 151 | Tb = sd->lab2Body(sd->getTrq()); | 
| 152 |  | 
| 153 | // get the angular momentum, and propagate a half step | 
| 154 |  | 
| 155 | ji = sd->getJ(); | 
| 156 |  | 
| 157 | ji += dt2*PhysicalConstants::energyConvert*Tb | 
| 158 | - dt2*thermostat.first *ji; | 
| 159 |  | 
| 160 | rotAlgo_->rotate(sd, ji, dt); | 
| 161 |  | 
| 162 | sd->setJ(ji); | 
| 163 | } | 
| 164 | } | 
| 165 |  | 
| 166 | } | 
| 167 |  | 
| 168 | flucQ_->moveA(); | 
| 169 | rattle_->constraintA(); | 
| 170 |  | 
| 171 | // Finally, evolve chi a half step (just like a velocity) using | 
| 172 | // temperature at time t, not time t+dt/2 | 
| 173 | this->evolveChiA(); | 
| 174 | //thermostat.first += dt2 * (instTemp / targetTemp_ - 1.0) | 
| 175 | //  / (tauThermostat_ * tauThermostat_); | 
| 176 | //thermostat.second += thermostat.first * dt2; | 
| 177 |  | 
| 178 | //snap->setThermostat(thermostat); | 
| 179 | } | 
| 180 |  | 
| 181 | void NVT::moveB() { | 
| 182 | SimInfo::MoleculeIterator i; | 
| 183 | Molecule::IntegrableObjectIterator  j; | 
| 184 | Molecule* mol; | 
| 185 | StuntDouble* sd; | 
| 186 |  | 
| 187 | Vector3d Tb; | 
| 188 | Vector3d ji; | 
| 189 | Vector3d vel; | 
| 190 | Vector3d frc; | 
| 191 | RealType mass; | 
| 192 | RealType instTemp; | 
| 193 | int index; | 
| 194 | // Set things up for the iteration: | 
| 195 |  | 
| 196 | /* | 
| 197 | * oldChi and prevChi are now oldChi_ and prevChi_ and are set in evolveChiB | 
| 198 | */ | 
| 199 | //RealType oldChi = thermostat.first; | 
| 200 | //RealType  prevChi; | 
| 201 |  | 
| 202 | index = 0; | 
| 203 | for (mol = info_->beginMolecule(i); mol != NULL; | 
| 204 | mol = info_->nextMolecule(i)) { | 
| 205 |  | 
| 206 | for (sd = mol->beginIntegrableObject(j); sd != NULL; | 
| 207 | sd = mol->nextIntegrableObject(j)) { | 
| 208 |  | 
| 209 | oldVel_[index] = sd->getVel(); | 
| 210 |  | 
| 211 | if (sd->isDirectional()) | 
| 212 | oldJi_[index] = sd->getJ(); | 
| 213 |  | 
| 214 | ++index; | 
| 215 | } | 
| 216 | } | 
| 217 |  | 
| 218 | // do the iteration: | 
| 219 |  | 
| 220 | for(int k = 0; k < maxIterNum_; k++) { | 
| 221 | index = 0; | 
| 222 | //instTemp = thermo.getTemperature(); | 
| 223 |  | 
| 224 | // evolve chi another half step using the temperature at t + dt/2 | 
| 225 |  | 
| 226 | /* | 
| 227 | * calls this files modified version of evolveChiB(); | 
| 228 | */ | 
| 229 | this->evolveChiB(); | 
| 230 |  | 
| 231 | /* | 
| 232 | * prevChi_ and thermostat.first are set in evolveChiB() | 
| 233 | */ | 
| 234 | //prevChi = thermostat.first; | 
| 235 | //thermostat.first = oldChi + dt2 * (instTemp / targetTemp_ - 1.0) | 
| 236 | //  / (tauThermostat_ * tauThermostat_); | 
| 237 |  | 
| 238 | /* | 
| 239 | * Since it is changed in a different method, need to get the updated version here | 
| 240 | */ | 
| 241 | pair<RealType, RealType> thermostat = snap->getThermostat(); | 
| 242 |  | 
| 243 | for (mol = info_->beginMolecule(i); mol != NULL; | 
| 244 | mol = info_->nextMolecule(i)) { | 
| 245 |  | 
| 246 | for (sd = mol->beginIntegrableObject(j); sd != NULL; | 
| 247 | sd = mol->nextIntegrableObject(j)) { | 
| 248 |  | 
| 249 | frc = sd->getFrc(); | 
| 250 | mass = sd->getMass(); | 
| 251 |  | 
| 252 | // velocity half step | 
| 253 |  | 
| 254 | vel = oldVel_[index] | 
| 255 | + dt2/mass*PhysicalConstants::energyConvert * frc | 
| 256 | - dt2*thermostat.first*oldVel_[index]; | 
| 257 |  | 
| 258 | sd->setVel(vel); | 
| 259 |  | 
| 260 | if (sd->isDirectional()) { | 
| 261 |  | 
| 262 | // get and convert the torque to body frame | 
| 263 |  | 
| 264 | Tb =  sd->lab2Body(sd->getTrq()); | 
| 265 |  | 
| 266 | ji = oldJi_[index] + dt2*PhysicalConstants::energyConvert*Tb | 
| 267 | - dt2*thermostat.first *oldJi_[index]; | 
| 268 |  | 
| 269 | sd->setJ(ji); | 
| 270 | } | 
| 271 |  | 
| 272 |  | 
| 273 | ++index; | 
| 274 | } | 
| 275 | } | 
| 276 |  | 
| 277 | rattle_->constraintB(); | 
| 278 |  | 
| 279 | /* | 
| 280 | * prevChi_ is defined in evolveChiB now | 
| 281 | */ | 
| 282 | //if (fabs(prevChi - thermostat.first) <= chiTolerance_) | 
| 283 | if (fabs(prevChi_ - thermostat.first) <= chiTolerance_) | 
| 284 | break; | 
| 285 |  | 
| 286 | } | 
| 287 |  | 
| 288 | flucQ_->moveB(); | 
| 289 |  | 
| 290 | /* | 
| 291 | * This has already happened in evolveChiB | 
| 292 | */ | 
| 293 | //thermostat.second += dt2 * thermostat.first; | 
| 294 | //snap->setThermostat(thermostat); | 
| 295 | } | 
| 296 |  | 
| 297 | void NVT::resetIntegrator() { | 
| 298 | snap->setThermostat(make_pair(0.0, 0.0)); | 
| 299 | } | 
| 300 |  | 
| 301 | RealType NVT::calcConservedQuantity() { | 
| 302 |  | 
| 303 | pair<RealType, RealType> thermostat = snap->getThermostat(); | 
| 304 | RealType conservedQuantity; | 
| 305 | RealType fkBT; | 
| 306 | RealType Energy; | 
| 307 | RealType thermostat_kinetic; | 
| 308 | RealType thermostat_potential; | 
| 309 |  | 
| 310 | fkBT = info_->getNdf() *PhysicalConstants::kB *targetTemp_; | 
| 311 |  | 
| 312 | Energy = thermo.getTotalEnergy(); | 
| 313 |  | 
| 314 | thermostat_kinetic = fkBT * tauThermostat_ * tauThermostat_ * thermostat.first * thermostat.first / (2.0 * PhysicalConstants::energyConvert); | 
| 315 |  | 
| 316 | thermostat_potential = fkBT * thermostat.second / PhysicalConstants::energyConvert; | 
| 317 |  | 
| 318 | conservedQuantity = Energy + thermostat_kinetic + thermostat_potential; | 
| 319 |  | 
| 320 | return conservedQuantity; | 
| 321 | } | 
| 322 |  | 
| 323 |  | 
| 324 | }//end namespace OpenMD |