| 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 "constraints/Rattle.hpp" | 
| 44 | #include "primitives/Molecule.hpp" | 
| 45 | #include "utils/simError.h" | 
| 46 | namespace OpenMD { | 
| 47 |  | 
| 48 | Rattle::Rattle(SimInfo* info) : info_(info), maxConsIteration_(10), | 
| 49 | consTolerance_(1.0e-6), doRattle_(false), | 
| 50 | currConstraintTime_(0.0) { | 
| 51 |  | 
| 52 | if (info_->getNGlobalConstraints() > 0) | 
| 53 | doRattle_ = true; | 
| 54 |  | 
| 55 | Globals* simParams = info_->getSimParams(); | 
| 56 |  | 
| 57 | if (simParams->haveDt()) { | 
| 58 | dt_ = simParams->getDt(); | 
| 59 | } else { | 
| 60 | sprintf(painCave.errMsg, | 
| 61 | "Rattle Error: dt is not set\n"); | 
| 62 | painCave.isFatal = 1; | 
| 63 | simError(); | 
| 64 | } | 
| 65 |  | 
| 66 | currentSnapshot_ = info_->getSnapshotManager()->getCurrentSnapshot(); | 
| 67 | if (simParams->haveConstraintTime()){ | 
| 68 | constraintTime_ = simParams->getConstraintTime(); | 
| 69 | } else { | 
| 70 | constraintTime_ = simParams->getStatusTime(); | 
| 71 | } | 
| 72 |  | 
| 73 | constraintOutputFile_ = getPrefix(info_->getFinalConfigFileName()) + | 
| 74 | ".constraintForces"; | 
| 75 |  | 
| 76 | // create ConstraintWriter | 
| 77 | constraintWriter_ = new ConstraintWriter(info_, | 
| 78 | constraintOutputFile_.c_str()); | 
| 79 |  | 
| 80 | if (!constraintWriter_){ | 
| 81 | sprintf(painCave.errMsg, "Failed to create ConstraintWriter\n"); | 
| 82 | painCave.isFatal = 1; | 
| 83 | simError(); | 
| 84 | } | 
| 85 | } | 
| 86 |  | 
| 87 | void Rattle::constraintA() { | 
| 88 | if (!doRattle_) return; | 
| 89 | doConstraint(&Rattle::constraintPairA); | 
| 90 | } | 
| 91 | void Rattle::constraintB() { | 
| 92 | if (!doRattle_) return; | 
| 93 | doConstraint(&Rattle::constraintPairB); | 
| 94 |  | 
| 95 | if (currentSnapshot_->getTime() >= currConstraintTime_){ | 
| 96 | Molecule* mol; | 
| 97 | SimInfo::MoleculeIterator mi; | 
| 98 | ConstraintPair* consPair; | 
| 99 | Molecule::ConstraintPairIterator cpi; | 
| 100 | std::list<ConstraintPair*> constraints; | 
| 101 | for (mol = info_->beginMolecule(mi); mol != NULL; | 
| 102 | mol = info_->nextMolecule(mi)) { | 
| 103 | for (consPair = mol->beginConstraintPair(cpi); consPair != NULL; | 
| 104 | consPair = mol->nextConstraintPair(cpi)) { | 
| 105 |  | 
| 106 | constraints.push_back(consPair); | 
| 107 | } | 
| 108 | } | 
| 109 | constraintWriter_->writeConstraintForces(constraints); | 
| 110 | currConstraintTime_ += constraintTime_; | 
| 111 | } | 
| 112 | } | 
| 113 |  | 
| 114 | void Rattle::doConstraint(ConstraintPairFuncPtr func) { | 
| 115 | if (!doRattle_) return; | 
| 116 |  | 
| 117 | Molecule* mol; | 
| 118 | SimInfo::MoleculeIterator mi; | 
| 119 | ConstraintElem* consElem; | 
| 120 | Molecule::ConstraintElemIterator cei; | 
| 121 | ConstraintPair* consPair; | 
| 122 | Molecule::ConstraintPairIterator cpi; | 
| 123 |  | 
| 124 | for (mol = info_->beginMolecule(mi); mol != NULL; | 
| 125 | mol = info_->nextMolecule(mi)) { | 
| 126 | for (consElem = mol->beginConstraintElem(cei); consElem != NULL; | 
| 127 | consElem = mol->nextConstraintElem(cei)) { | 
| 128 | consElem->setMoved(true); | 
| 129 | consElem->setMoving(false); | 
| 130 | } | 
| 131 | } | 
| 132 |  | 
| 133 | //main loop of constraint algorithm | 
| 134 | bool done = false; | 
| 135 | int iteration = 0; | 
| 136 | while(!done && iteration < maxConsIteration_){ | 
| 137 | done = true; | 
| 138 |  | 
| 139 | //loop over every constraint pair | 
| 140 |  | 
| 141 | for (mol = info_->beginMolecule(mi); mol != NULL; | 
| 142 | mol = info_->nextMolecule(mi)) { | 
| 143 | for (consPair = mol->beginConstraintPair(cpi); consPair != NULL; | 
| 144 | consPair = mol->nextConstraintPair(cpi)) { | 
| 145 |  | 
| 146 |  | 
| 147 | //dispatch constraint algorithm | 
| 148 | if(consPair->isMoved()) { | 
| 149 | int exeStatus = (this->*func)(consPair); | 
| 150 |  | 
| 151 | switch(exeStatus){ | 
| 152 | case consFail: | 
| 153 | sprintf(painCave.errMsg, | 
| 154 | "Constraint failure in Rattle::constrainA, " | 
| 155 | "Constraint Fail\n"); | 
| 156 | painCave.isFatal = 1; | 
| 157 | simError(); | 
| 158 |  | 
| 159 | break; | 
| 160 | case consSuccess: | 
| 161 | // constrain the pair by moving two elements | 
| 162 | done = false; | 
| 163 | consPair->getConsElem1()->setMoving(true); | 
| 164 | consPair->getConsElem2()->setMoving(true); | 
| 165 | break; | 
| 166 | case consAlready: | 
| 167 | // current pair is already constrained, do not need to | 
| 168 | // move the elements | 
| 169 | break; | 
| 170 | default: | 
| 171 | sprintf(painCave.errMsg, "ConstraintAlgorithm::doConstraint() " | 
| 172 | "Error: unrecognized status"); | 
| 173 | painCave.isFatal = 1; | 
| 174 | simError(); | 
| 175 | break; | 
| 176 | } | 
| 177 | } | 
| 178 | } | 
| 179 | }//end for(iter->first()) | 
| 180 |  | 
| 181 |  | 
| 182 | for (mol = info_->beginMolecule(mi); mol != NULL; | 
| 183 | mol = info_->nextMolecule(mi)) { | 
| 184 | for (consElem = mol->beginConstraintElem(cei); consElem != NULL; | 
| 185 | consElem = mol->nextConstraintElem(cei)) { | 
| 186 | consElem->setMoved(consElem->getMoving()); | 
| 187 | consElem->setMoving(false); | 
| 188 | } | 
| 189 | } | 
| 190 |  | 
| 191 | iteration++; | 
| 192 | }//end while | 
| 193 |  | 
| 194 | if (!done){ | 
| 195 | sprintf(painCave.errMsg, | 
| 196 | "Constraint failure in Rattle::constrainA, " | 
| 197 | "too many iterations: %d\n", | 
| 198 | iteration); | 
| 199 | painCave.isFatal = 1; | 
| 200 | simError(); | 
| 201 | } | 
| 202 | } | 
| 203 |  | 
| 204 | int Rattle::constraintPairA(ConstraintPair* consPair){ | 
| 205 |  | 
| 206 | ConstraintElem* consElem1 = consPair->getConsElem1(); | 
| 207 | ConstraintElem* consElem2 = consPair->getConsElem2(); | 
| 208 |  | 
| 209 | Vector3d posA = consElem1->getPos(); | 
| 210 | Vector3d posB = consElem2->getPos(); | 
| 211 |  | 
| 212 | Vector3d pab = posA -posB; | 
| 213 |  | 
| 214 | //periodic boundary condition | 
| 215 |  | 
| 216 | currentSnapshot_->wrapVector(pab); | 
| 217 |  | 
| 218 | RealType pabsq = pab.lengthSquare(); | 
| 219 |  | 
| 220 | RealType rabsq = consPair->getConsDistSquare(); | 
| 221 | RealType diffsq = rabsq - pabsq; | 
| 222 |  | 
| 223 | // the original rattle code from alan tidesley | 
| 224 | if (fabs(diffsq) > (consTolerance_ * rabsq * 2)){ | 
| 225 |  | 
| 226 | Vector3d oldPosA = consElem1->getPrevPos(); | 
| 227 | Vector3d oldPosB = consElem2->getPrevPos(); | 
| 228 |  | 
| 229 | Vector3d rab = oldPosA - oldPosB; | 
| 230 |  | 
| 231 | currentSnapshot_->wrapVector(rab); | 
| 232 |  | 
| 233 | RealType rpab = dot(rab, pab); | 
| 234 | RealType rpabsq = rpab * rpab; | 
| 235 |  | 
| 236 | if (rpabsq < (rabsq * -diffsq)){ | 
| 237 | return consFail; | 
| 238 | } | 
| 239 |  | 
| 240 | RealType rma = 1.0 / consElem1->getMass(); | 
| 241 | RealType rmb = 1.0 / consElem2->getMass(); | 
| 242 |  | 
| 243 | RealType gab = diffsq / (2.0 * (rma + rmb) * rpab); | 
| 244 |  | 
| 245 | Vector3d delta = rab * gab; | 
| 246 |  | 
| 247 | //set atom1's position | 
| 248 | posA += rma * delta; | 
| 249 | consElem1->setPos(posA); | 
| 250 |  | 
| 251 | //set atom2's position | 
| 252 | posB -= rmb * delta; | 
| 253 | consElem2->setPos(posB); | 
| 254 |  | 
| 255 | delta /= dt_; | 
| 256 |  | 
| 257 | //set atom1's velocity | 
| 258 | Vector3d velA = consElem1->getVel(); | 
| 259 | velA += rma * delta; | 
| 260 | consElem1->setVel(velA); | 
| 261 |  | 
| 262 | //set atom2's velocity | 
| 263 | Vector3d velB = consElem2->getVel(); | 
| 264 | velB -= rmb * delta; | 
| 265 | consElem2->setVel(velB); | 
| 266 |  | 
| 267 | // report the constraint force back to the constraint pair: | 
| 268 | consPair->setConstraintForce(gab); | 
| 269 | return consSuccess; | 
| 270 | } | 
| 271 | else | 
| 272 | return consAlready; | 
| 273 |  | 
| 274 | } | 
| 275 |  | 
| 276 |  | 
| 277 | int Rattle::constraintPairB(ConstraintPair* consPair){ | 
| 278 | ConstraintElem* consElem1 = consPair->getConsElem1(); | 
| 279 | ConstraintElem* consElem2 = consPair->getConsElem2(); | 
| 280 |  | 
| 281 |  | 
| 282 | Vector3d velA = consElem1->getVel(); | 
| 283 | Vector3d velB = consElem2->getVel(); | 
| 284 |  | 
| 285 | Vector3d dv = velA - velB; | 
| 286 |  | 
| 287 | Vector3d posA = consElem1->getPos(); | 
| 288 | Vector3d posB = consElem2->getPos(); | 
| 289 |  | 
| 290 | Vector3d rab = posA - posB; | 
| 291 |  | 
| 292 | currentSnapshot_->wrapVector(rab); | 
| 293 |  | 
| 294 | RealType rma = 1.0 / consElem1->getMass(); | 
| 295 | RealType rmb = 1.0 / consElem2->getMass(); | 
| 296 |  | 
| 297 | RealType rvab = dot(rab, dv); | 
| 298 |  | 
| 299 | RealType gab = -rvab / ((rma + rmb) * consPair->getConsDistSquare()); | 
| 300 |  | 
| 301 | if (fabs(gab) > consTolerance_){ | 
| 302 | Vector3d delta = rab * gab; | 
| 303 |  | 
| 304 | velA += rma * delta; | 
| 305 | consElem1->setVel(velA); | 
| 306 |  | 
| 307 | velB -= rmb * delta; | 
| 308 | consElem2->setVel(velB); | 
| 309 |  | 
| 310 | // report the constraint force back to the constraint pair: | 
| 311 | consPair->setConstraintForce(gab); | 
| 312 | return consSuccess; | 
| 313 | } | 
| 314 | else | 
| 315 | return consAlready; | 
| 316 |  | 
| 317 | } | 
| 318 |  | 
| 319 | } |