| 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. Acknowledgement of the program authors must be made in any | 
| 10 | *    publication of scientific results based in part on use of the | 
| 11 | *    program.  An acceptable form of acknowledgement is citation of | 
| 12 | *    the article in which the program was described (Matthew | 
| 13 | *    A. Meineke, Charles F. Vardeman II, Teng Lin, Christopher | 
| 14 | *    J. Fennell and J. Daniel Gezelter, "OOPSE: An Object-Oriented | 
| 15 | *    Parallel Simulation Engine for Molecular Dynamics," | 
| 16 | *    J. Comput. Chem. 26, pp. 252-271 (2005)) | 
| 17 | * | 
| 18 | * 2. Redistributions of source code must retain the above copyright | 
| 19 | *    notice, this list of conditions and the following disclaimer. | 
| 20 | * | 
| 21 | * 3. Redistributions in binary form must reproduce the above copyright | 
| 22 | *    notice, this list of conditions and the following disclaimer in the | 
| 23 | *    documentation and/or other materials provided with the | 
| 24 | *    distribution. | 
| 25 | * | 
| 26 | * This software is provided "AS IS," without a warranty of any | 
| 27 | * kind. All express or implied conditions, representations and | 
| 28 | * warranties, including any implied warranty of merchantability, | 
| 29 | * fitness for a particular purpose or non-infringement, are hereby | 
| 30 | * excluded.  The University of Notre Dame and its licensors shall not | 
| 31 | * be liable for any damages suffered by licensee as a result of | 
| 32 | * using, modifying or distributing the software or its | 
| 33 | * derivatives. In no event will the University of Notre Dame or its | 
| 34 | * licensors be liable for any lost revenue, profit or data, or for | 
| 35 | * direct, indirect, special, consequential, incidental or punitive | 
| 36 | * damages, however caused and regardless of the theory of liability, | 
| 37 | * arising out of the use of or inability to use software, even if the | 
| 38 | * University of Notre Dame has been advised of the possibility of | 
| 39 | * such damages. | 
| 40 | */ | 
| 41 |  | 
| 42 | #include "integrators/Velocitizer.hpp" | 
| 43 | #include "math/SquareMatrix3.hpp" | 
| 44 | #include "primitives/Molecule.hpp" | 
| 45 | #include "primitives/StuntDouble.hpp" | 
| 46 |  | 
| 47 | #ifndef IS_MPI | 
| 48 | #include "math/SeqRandNumGen.hpp" | 
| 49 | #else | 
| 50 | #include "math/ParallelRandNumGen.hpp" | 
| 51 | #endif | 
| 52 |  | 
| 53 | /* Remove me after testing*/ | 
| 54 | #include <cstdio> | 
| 55 | #include <iostream> | 
| 56 | /*End remove me*/ | 
| 57 |  | 
| 58 | namespace oopse { | 
| 59 |  | 
| 60 | Velocitizer::Velocitizer(SimInfo* info) : info_(info) { | 
| 61 |  | 
| 62 | int seedValue; | 
| 63 | Globals * simParams = info->getSimParams(); | 
| 64 |  | 
| 65 | #ifndef IS_MPI | 
| 66 | if (simParams->haveSeed()) { | 
| 67 | seedValue = simParams->getSeed(); | 
| 68 | randNumGen_ = new SeqRandNumGen(seedValue); | 
| 69 | }else { | 
| 70 | randNumGen_ = new SeqRandNumGen(); | 
| 71 | } | 
| 72 | #else | 
| 73 | if (simParams->haveSeed()) { | 
| 74 | seedValue = simParams->getSeed(); | 
| 75 | randNumGen_ = new ParallelRandNumGen(seedValue); | 
| 76 | }else { | 
| 77 | randNumGen_ = new ParallelRandNumGen(); | 
| 78 | } | 
| 79 | #endif | 
| 80 | } | 
| 81 |  | 
| 82 | Velocitizer::~Velocitizer() { | 
| 83 | delete randNumGen_; | 
| 84 | } | 
| 85 |  | 
| 86 | void Velocitizer::velocitize(double temperature) { | 
| 87 | Vector3d aVel; | 
| 88 | Vector3d aJ; | 
| 89 | Mat3x3d I; | 
| 90 | int l; | 
| 91 | int m; | 
| 92 | int n; | 
| 93 | Vector3d vdrift; | 
| 94 | double vbar; | 
| 95 | /**@todo refactory kb */ | 
| 96 | const double kb = 8.31451e-7; // kb in amu, angstroms, fs, etc. | 
| 97 | double av2; | 
| 98 | double kebar; | 
| 99 |  | 
| 100 | Globals * simParams = info_->getSimParams(); | 
| 101 |  | 
| 102 | SimInfo::MoleculeIterator i; | 
| 103 | Molecule::IntegrableObjectIterator j; | 
| 104 | Molecule * mol; | 
| 105 | StuntDouble * integrableObject; | 
| 106 |  | 
| 107 |  | 
| 108 |  | 
| 109 | kebar = kb * temperature * info_->getNdfRaw() / (2.0 * info_->getNdf()); | 
| 110 |  | 
| 111 | for( mol = info_->beginMolecule(i); mol != NULL; | 
| 112 | mol = info_->nextMolecule(i) ) { | 
| 113 | for( integrableObject = mol->beginIntegrableObject(j); | 
| 114 | integrableObject != NULL; | 
| 115 | integrableObject = mol->nextIntegrableObject(j) ) { | 
| 116 |  | 
| 117 | // uses equipartition theory to solve for vbar in angstrom/fs | 
| 118 |  | 
| 119 | av2 = 2.0 * kebar / integrableObject->getMass(); | 
| 120 | vbar = sqrt(av2); | 
| 121 |  | 
| 122 | // picks random velocities from a gaussian distribution | 
| 123 | // centered on vbar | 
| 124 |  | 
| 125 | for( int k = 0; k < 3; k++ ) { | 
| 126 | aVel[k] = vbar * randNumGen_->randNorm(0.0, 1.0); | 
| 127 | } | 
| 128 |  | 
| 129 | integrableObject->setVel(aVel); | 
| 130 |  | 
| 131 | if (integrableObject->isDirectional()) { | 
| 132 | I = integrableObject->getI(); | 
| 133 |  | 
| 134 | if (integrableObject->isLinear()) { | 
| 135 | l = integrableObject->linearAxis(); | 
| 136 | m = (l + 1) % 3; | 
| 137 | n = (l + 2) % 3; | 
| 138 |  | 
| 139 | aJ[l] = 0.0; | 
| 140 | vbar = sqrt(2.0 * kebar * I(m, m)); | 
| 141 | aJ[m] = vbar * randNumGen_->randNorm(0.0, 1.0); | 
| 142 | vbar = sqrt(2.0 * kebar * I(n, n)); | 
| 143 | aJ[n] = vbar * randNumGen_->randNorm(0.0, 1.0); | 
| 144 | } else { | 
| 145 | for( int k = 0; k < 3; k++ ) { | 
| 146 | vbar = sqrt(2.0 * kebar * I(k, k)); | 
| 147 | aJ[k] = vbar *randNumGen_->randNorm(0.0, 1.0); | 
| 148 | } | 
| 149 | } // else isLinear | 
| 150 |  | 
| 151 | integrableObject->setJ(aJ); | 
| 152 | }     //isDirectional | 
| 153 | } | 
| 154 | }             //end for (mol = beginMolecule(i); ...) | 
| 155 |  | 
| 156 |  | 
| 157 |  | 
| 158 | removeComDrift(); | 
| 159 | // Remove angular drift if we are not using periodic boundary conditions. | 
| 160 | if(!simParams->getPBC()) removeAngularDrift(); | 
| 161 |  | 
| 162 | } | 
| 163 |  | 
| 164 |  | 
| 165 |  | 
| 166 | void Velocitizer::removeComDrift() { | 
| 167 | // Get the Center of Mass drift velocity. | 
| 168 | Vector3d vdrift = info_->getComVel(); | 
| 169 |  | 
| 170 | SimInfo::MoleculeIterator i; | 
| 171 | Molecule::IntegrableObjectIterator j; | 
| 172 | Molecule * mol; | 
| 173 | StuntDouble * integrableObject; | 
| 174 |  | 
| 175 | //  Corrects for the center of mass drift. | 
| 176 | // sums all the momentum and divides by total mass. | 
| 177 | for( mol = info_->beginMolecule(i); mol != NULL; | 
| 178 | mol = info_->nextMolecule(i) ) { | 
| 179 | for( integrableObject = mol->beginIntegrableObject(j); | 
| 180 | integrableObject != NULL; | 
| 181 | integrableObject = mol->nextIntegrableObject(j) ) { | 
| 182 | integrableObject->setVel(integrableObject->getVel() - vdrift); | 
| 183 | } | 
| 184 | } | 
| 185 |  | 
| 186 | } | 
| 187 |  | 
| 188 |  | 
| 189 | void Velocitizer::removeAngularDrift() { | 
| 190 | // Get the Center of Mass drift velocity. | 
| 191 |  | 
| 192 | Vector3d vdrift; | 
| 193 | Vector3d com; | 
| 194 |  | 
| 195 | info_->getComAll(com,vdrift); | 
| 196 |  | 
| 197 | Mat3x3d inertiaTensor; | 
| 198 | Vector3d angularMomentum; | 
| 199 | Vector3d omega; | 
| 200 |  | 
| 201 |  | 
| 202 |  | 
| 203 | info_->getInertiaTensor(inertiaTensor,angularMomentum); | 
| 204 | // We now need the inverse of the inertia tensor. | 
| 205 |  | 
| 206 | std::cerr << "Angular Momentum before is " | 
| 207 | << angularMomentum <<  std::endl; | 
| 208 | std::cerr << "Inertia Tensor before is " | 
| 209 | << inertiaTensor <<  std::endl; | 
| 210 |  | 
| 211 |  | 
| 212 | inertiaTensor =inertiaTensor.inverse(); | 
| 213 | std::cerr << "Inertia Tensor after inverse is " | 
| 214 | << inertiaTensor <<  std::endl; | 
| 215 |  | 
| 216 | omega = inertiaTensor*angularMomentum; | 
| 217 |  | 
| 218 | SimInfo::MoleculeIterator i; | 
| 219 | Molecule::IntegrableObjectIterator j; | 
| 220 | Molecule * mol; | 
| 221 | StuntDouble * integrableObject; | 
| 222 | Vector3d tempComPos; | 
| 223 |  | 
| 224 | //  Corrects for the center of mass angular drift. | 
| 225 | // sums all the angular momentum and divides by total mass. | 
| 226 | for( mol = info_->beginMolecule(i); mol != NULL; | 
| 227 | mol = info_->nextMolecule(i) ) { | 
| 228 | for( integrableObject = mol->beginIntegrableObject(j); | 
| 229 | integrableObject != NULL; | 
| 230 | integrableObject = mol->nextIntegrableObject(j) ) { | 
| 231 | tempComPos = integrableObject->getPos()-com; | 
| 232 | integrableObject->setVel((integrableObject->getVel() - vdrift)-cross(omega,tempComPos)); | 
| 233 | } | 
| 234 | } | 
| 235 |  | 
| 236 | angularMomentum = info_->getAngularMomentum(); | 
| 237 | std::cerr << "Angular Momentum after is " | 
| 238 | << angularMomentum <<  std::endl; | 
| 239 |  | 
| 240 |  | 
| 241 | } | 
| 242 |  | 
| 243 |  | 
| 244 |  | 
| 245 |  | 
| 246 | } |