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tim |
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#include <math.h> |
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#include "brains/SimInfo.hpp" |
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#include "brains/Thermo.hpp" |
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#include "integrators/NPT.hpp" |
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#include "utils/simError.h" |
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// Basic isotropic thermostating and barostating via the Melchionna |
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// modification of the Hoover algorithm: |
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// |
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// Melchionna, S., Ciccotti, G., and Holian, B. L., 1993, |
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// Molec. Phys., 78, 533. |
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// |
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// and |
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// |
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// Hoover, W. G., 1986, Phys. Rev. A, 34, 2499. |
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namespace oopse { |
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NPT::NPT(SimInfo* info) : |
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VelocityVerletIntegrator(info), chiTolerance(1e-6), etaTolerance(1e-6) { |
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Globals* globals = info_->getGlobals(); |
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if (globals->getUseInitXSstate()) { |
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Snapshot* currSnapshot = info_->getSnapshotManager()->getCurrentSnapshot(); |
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currSnapshot->setChi(0.0); |
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currSnapshot->setIntegralOfChiDt(0.0); |
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} |
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if (!globals->haveTargetTemp()) { |
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sprintf(painCave.errMsg, "You can't use the NVT integrator without a targetTemp!\n"); |
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painCave.isFatal = 1; |
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painCave.severity = OOPSE_ERROR; |
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simError(); |
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} else { |
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targetTemp = globals->getTargetTemp(); |
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} |
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// We must set tauThermostat |
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if (!globals->haveTauThermostat()) { |
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sprintf(painCave.errMsg, "If you use the constant temperature\n" |
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"\tintegrator, you must set tauThermostat_.\n"); |
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painCave.severity = OOPSE_ERROR; |
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painCave.isFatal = 1; |
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simError(); |
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} else { |
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tauThermostat = globals->getTauThermostat(); |
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} |
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if (!globals->haveTargetPressure()) { |
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sprintf(painCave.errMsg, "NPT error: You can't use the NPT integrator\n" |
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" without a targetPressure!\n"); |
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painCave.isFatal = 1; |
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simError(); |
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} else { |
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targetPressure = globals->getTargetPressure(); |
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} |
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if (!globals->haveTauBarostat()) { |
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sprintf(painCave.errMsg, |
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"If you use the NPT integrator, you must set tauBarostat.\n"); |
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painCave.severity = OOPSE_ERROR; |
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painCave.isFatal = 1; |
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simError(); |
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} else { |
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tauBarostat = globals->getTauBarostat(); |
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} |
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tt2 = tauThermostat * tauThermostat; |
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tb2 = tauBarostat * tauBarostat; |
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update(); |
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} |
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NPT::~NPT() { |
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} |
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void NPT::update() { |
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oldPos.resize(info_->getNIntegrableObjects()); |
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oldVel.resize(info_->getNIntegrableObjects()); |
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oldJi.resize(info_->getNIntegrableObjects()); |
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// We need NkBT a lot, so just set it here: This is the RAW number |
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// of integrableObjects, so no subtraction or addition of constraints or |
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// orientational degrees of freedom: |
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NkBT = info_->getNGlobalIntegrableObjects()*kB *targetTemp; |
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// fkBT is used because the thermostat operates on more degrees of freedom |
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// than the barostat (when there are particles with orientational degrees |
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// of freedom). |
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fkBT = info_->getNdf()*kB *targetTemp; |
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} |
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void NPT::moveA() { |
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typename SimInfo::MoleculeIterator i; |
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typename Molecule::IntegrableObjectIterator j; |
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Molecule* mol; |
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StuntDouble* integrableObject; |
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Vector3d Tb, ji; |
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double mass; |
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Vector3d vel; |
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Vector3d pos; |
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Vector3d frc; |
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Vector3d sc; |
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Vector3d COM; |
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int index; |
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instaTemp = tStats->getTemperature(); |
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tStats->getPressureTensor(press); |
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instaPress = p_convert * (press(0, 0) + press(1, 1) + press(2, 2)) / 3.0; |
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instaVol = tStats->getVolume(); |
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tStats->getCOM(COM); |
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//evolve velocity half step |
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calcVelScale(); |
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for (mol = info_->beginMolecule(i); mol != NULL; mol = info_->nextMolecule(i)) { |
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for (integrableObject = mol->beginIntegrableObject(j); integrableObject != NULL; |
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integrableObject = mol->nextIntegrableObject(j)) { |
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vel = integrableObject->getVel(); |
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frc = integrableObject->getFrc(); |
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mass = integrableObject->getMass(); |
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getVelScaleA(sc, vel); |
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// velocity half step (use chi from previous step here): |
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//vel[j] += dt2 * ((frc[j] / mass) * eConvert - sc[j]); |
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vel += dt2*eConvert/mass* frc - dt2*sc; |
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integrableObject->setVel(vel); |
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if (integrableObject->isDirectional()) { |
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// get and convert the torque to body frame |
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Tb = integrableObject->getTrq(); |
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integrableObject->lab2Body(Tb); |
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// get the angular momentum, and propagate a half step |
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ji = integrableObject->getJ(); |
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//ji[j] += dt2 * (Tb[j] * eConvert - ji[j]*chi); |
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ji += dt2*eConvert * Tb - dt2*chi* ji; |
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this->rotationPropagation(integrableObject, ji); |
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integrableObject->setJ(ji); |
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} |
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} |
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} |
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// evolve chi and eta half step |
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evolveChiA(); |
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evolveEtaA(); |
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//calculate the integral of chidt |
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integralOfChidt += dt2 * chi; |
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index = 0; |
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for (mol = info_->beginMolecule(i); mol != NULL; mol = info_->nextMolecule(i)) { |
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for (integrableObject = mol->beginIntegrableObject(j); integrableObject != NULL; |
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integrableObject = mol->nextIntegrableObject(j)) { |
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oldPos[index++] = integrableObject->getPos(); |
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} |
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} |
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//the first estimation of r(t+dt) is equal to r(t) |
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for(int k = 0; k < maxIterNum_; k++) { |
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index = 0; |
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for (mol = info_->beginMolecule(i); mol != NULL; mol = info_->nextMolecule(i)) { |
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for (integrableObject = mol->beginIntegrableObject(j); integrableObject != NULL; |
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integrableObject = mol->nextIntegrableObject(j)) { |
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vel = integrableObject->getVel(); |
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pos = integrableObject->getPos(); |
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this->getPosScale(pos, COM, index, sc); |
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pos = oldPos[index] + dt * (vel + sc); |
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integrableObject->setPos(pos); |
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++index; |
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} |
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} |
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//constraintAlgorithm->doConstrainA(); |
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} |
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// Scale the box after all the positions have been moved: |
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this->scaleSimBox(); |
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} |
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void NPT::moveB(void) { |
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typename SimInfo::MoleculeIterator i; |
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typename Molecule::IntegrableObjectIterator j; |
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Molecule* mol; |
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StuntDouble* integrableObject; |
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int index; |
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Vector3d Tb; |
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Vector3d ji; |
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Vector3d sc; |
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Vector3d vel; |
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Vector3d frc; |
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double mass; |
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//save velocity and angular momentum |
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index = 0; |
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for (mol = info_->beginMolecule(i); mol != NULL; mol = info_->nextMolecule(i)) { |
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for (integrableObject = mol->beginIntegrableObject(j); integrableObject != NULL; |
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integrableObject = mol->nextIntegrableObject(j)) { |
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oldVel[index] = integrableObject->getVel(); |
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oldJi[3 * i + j] = integrableObject->getJ(); |
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++index; |
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} |
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} |
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// do the iteration: |
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instaVol = tStats->getVolume(); |
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for(int k = 0; k < maxIterNum_; k++) { |
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instaTemp = tStats->getTemperature(); |
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instaPress = tStats->getPressure(); |
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// evolve chi another half step using the temperature at t + dt/2 |
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this->evolveChiB(); |
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this->evolveEtaB(); |
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this->calcVelScale(); |
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index = 0; |
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for (mol = info_->beginMolecule(i); mol != NULL; mol = info_->nextMolecule(i)) { |
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for (integrableObject = mol->beginIntegrableObject(j); integrableObject != NULL; |
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integrableObject = mol->nextIntegrableObject(j)) { |
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integrableObject->getFrc(frc); |
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vel = integrableObject->getVel(); |
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mass = integrableObject->getMass(); |
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getVelScaleB(sc, i); |
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// velocity half step |
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//vel[j] = oldVel[3 * i + j] + dt2 *((frc[j] / mass) * eConvert - sc[j]); |
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vel = oldVel[index] + dt2*eConvert/mass* frc - dt2*sc; |
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integrableObject->setVel(vel); |
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if (integrableObject->isDirectional()) { |
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// get and convert the torque to body frame |
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Tb = integrableObject->getTrq(); |
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integrableObject->lab2Body(Tb); |
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//ji[j] = oldJi[3*i + j] + dt2 * (Tb[j] * eConvert - oldJi[3*i+j]*chi); |
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ji = oldJi[index] + dt2*eConvert*Tb - dt2*chi*oldJi[index]; |
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integrableObject->setJ(ji); |
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} |
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++index; |
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} |
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} |
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//constraintAlgorithm->doConstrainB(); |
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if (this->chiConverged() && this->etaConverged()) |
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break; |
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} |
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//calculate integral of chidt |
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integralOfChidt += dt2 * chi; |
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} |
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void NPT::evolveChiA() { |
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chi += dt2 * (instaTemp / targetTemp - 1.0) / tt2; |
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oldChi = chi; |
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} |
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void NPT::evolveChiB() { |
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prevChi = chi; |
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chi = oldChi + dt2 * (instaTemp / targetTemp - 1.0) / tt2; |
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} |
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bool NPT::chiConverged() { |
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return (fabs(prevChi - chi) <= chiTolerance); |
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} |
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} |