src/integrators/NVT.cpp

/*
 * Copyright (c) 2005 The University of Notre Dame. All Rights Reserved.
 *
 * The University of Notre Dame grants you ("Licensee") a
 * non-exclusive, royalty free, license to use, modify and
 * redistribute this software in source and binary code form, provided
 * that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the
 *    distribution.
 *
 * This software is provided "AS IS," without a warranty of any
 * kind. All express or implied conditions, representations and
 * warranties, including any implied warranty of merchantability,
 * fitness for a particular purpose or non-infringement, are hereby
 * excluded.  The University of Notre Dame and its licensors shall not
 * be liable for any damages suffered by licensee as a result of
 * using, modifying or distributing the software or its
 * derivatives. In no event will the University of Notre Dame or its
 * licensors be liable for any lost revenue, profit or data, or for
 * direct, indirect, special, consequential, incidental or punitive
 * damages, however caused and regardless of the theory of liability,
 * arising out of the use of or inability to use software, even if the
 * University of Notre Dame has been advised of the possibility of
 * such damages.
 *
 * SUPPORT OPEN SCIENCE!  If you use OpenMD or its source code in your
 * research, please cite the appropriate papers when you publish your
 * work.  Good starting points are:
 *                                                                      
 * [1]  Meineke, et al., J. Comp. Chem. 26, 252-271 (2005).             
 * [2]  Fennell & Gezelter, J. Chem. Phys. 124, 234104 (2006).          
 * [3]  Sun, Lin & Gezelter, J. Chem. Phys. 128, 24107 (2008).          
 * [4]  Kuang & Gezelter,  J. Chem. Phys. 133, 164101 (2010).
 * [5]  Vardeman, Stocker & Gezelter, J. Chem. Theory Comput. 7, 834 (2011).
 */
 
#include "integrators/NVT.hpp"
#include "primitives/Molecule.hpp"
#include "utils/simError.h"
#include "utils/PhysicalConstants.hpp"

namespace OpenMD {

  NVT::NVT(SimInfo* info) : VelocityVerletIntegrator(info), chiTolerance_ (1e-6), maxIterNum_(4) {

    Globals* simParams = info_->getSimParams();

    if (!simParams->getUseIntialExtendedSystemState()) {
      Snapshot* currSnapshot = info_->getSnapshotManager()->getCurrentSnapshot();
      currSnapshot->setChi(0.0);
      currSnapshot->setIntegralOfChiDt(0.0);
    }
    
    if (!simParams->haveTargetTemp()) {
      sprintf(painCave.errMsg, "You can't use the NVT integrator without a targetTemp_!\n");
      painCave.isFatal = 1;
      painCave.severity = OPENMD_ERROR;
      simError();
    } else {
      targetTemp_ = simParams->getTargetTemp();
    }

    // We must set tauThermostat.

    if (!simParams->haveTauThermostat()) {
      sprintf(painCave.errMsg, "If you use the constant temperature\n"
              "\tintegrator, you must set tauThermostat.\n");

      painCave.severity = OPENMD_ERROR;
      painCave.isFatal = 1;
      simError();
    } else {
      tauThermostat_ = simParams->getTauThermostat();
    }

    updateSizes();
  }

  void NVT::doUpdateSizes() {
    oldVel_.resize(info_->getNIntegrableObjects());
    oldJi_.resize(info_->getNIntegrableObjects());
  }
  void NVT::moveA() {
    SimInfo::MoleculeIterator i;
    Molecule::IntegrableObjectIterator  j;
    Molecule* mol;
    StuntDouble* integrableObject;
    Vector3d Tb;
    Vector3d ji;
    RealType mass;
    Vector3d vel;
    Vector3d pos;
    Vector3d frc;

    RealType chi = currentSnapshot_->getChi();
    RealType integralOfChidt = currentSnapshot_->getIntegralOfChiDt();
    
    // We need the temperature at time = t for the chi update below:

    RealType instTemp = thermo.getTemperature();

    for (mol = info_->beginMolecule(i); mol != NULL; mol = info_->nextMolecule(i)) {
      for (integrableObject = mol->beginIntegrableObject(j); integrableObject != NULL;
           integrableObject = mol->nextIntegrableObject(j)) {

        vel = integrableObject->getVel();
        pos = integrableObject->getPos();
        frc = integrableObject->getFrc();

        mass = integrableObject->getMass();

        // velocity half step  (use chi from previous step here):
        //vel[j] += dt2 * ((frc[j] / mass ) * PhysicalConstants::energyConvert - vel[j]*chi);
        vel += dt2 *PhysicalConstants::energyConvert/mass*frc - dt2*chi*vel;
        
        // position whole step
        //pos[j] += dt * vel[j];
        pos += dt * vel;

        integrableObject->setVel(vel);
        integrableObject->setPos(pos);

        if (integrableObject->isDirectional()) {

          //convert the torque to body frame
          Tb = integrableObject->lab2Body(integrableObject->getTrq());

          // get the angular momentum, and propagate a half step

          ji = integrableObject->getJ();

          //ji[j] += dt2 * (Tb[j] * PhysicalConstants::energyConvert - ji[j]*chi);
          ji += dt2*PhysicalConstants::energyConvert*Tb - dt2*chi *ji;
          rotAlgo_->rotate(integrableObject, ji, dt);

          integrableObject->setJ(ji);
        }
      }

    }
    
    flucQ_->moveA();
    rattle_->constraintA();

    // Finally, evolve chi a half step (just like a velocity) using
    // temperature at time t, not time t+dt/2

    
    chi += dt2 * (instTemp / targetTemp_ - 1.0) / (tauThermostat_ * tauThermostat_);
    integralOfChidt += chi * dt2;

    currentSnapshot_->setChi(chi);
    currentSnapshot_->setIntegralOfChiDt(integralOfChidt);
  }

  void NVT::moveB() {
    SimInfo::MoleculeIterator i;
    Molecule::IntegrableObjectIterator  j;
    Molecule* mol;
    StuntDouble* integrableObject;
    
    Vector3d Tb;
    Vector3d ji;    
    Vector3d vel;
    Vector3d frc;
    RealType mass;
    RealType instTemp;
    int index;
    // Set things up for the iteration:

    RealType chi = currentSnapshot_->getChi();
    RealType oldChi = chi;
    RealType  prevChi;
    RealType integralOfChidt = currentSnapshot_->getIntegralOfChiDt();

    index = 0;
    for (mol = info_->beginMolecule(i); mol != NULL; mol = info_->nextMolecule(i)) {
      for (integrableObject = mol->beginIntegrableObject(j); integrableObject != NULL;
           integrableObject = mol->nextIntegrableObject(j)) {

        oldVel_[index] = integrableObject->getVel();
        
        if (integrableObject->isDirectional()) 
          oldJi_[index] = integrableObject->getJ();                
        
        ++index;    
      }           
    }

    // do the iteration:

    for(int k = 0; k < maxIterNum_; k++) {
      index = 0;
      instTemp = thermo.getTemperature();

      // evolve chi another half step using the temperature at t + dt/2

      prevChi = chi;
      chi = oldChi + dt2 * (instTemp / targetTemp_ - 1.0) / (tauThermostat_ * tauThermostat_);

      for (mol = info_->beginMolecule(i); mol != NULL; mol = info_->nextMolecule(i)) {
        for (integrableObject = mol->beginIntegrableObject(j); integrableObject != NULL;
             integrableObject = mol->nextIntegrableObject(j)) {

          frc = integrableObject->getFrc();
          vel = integrableObject->getVel();

          mass = integrableObject->getMass();

          // velocity half step
          //for(j = 0; j < 3; j++)
          //    vel[j] = oldVel_[3*i+j] + dt2 * ((frc[j] / mass ) * PhysicalConstants::energyConvert - oldVel_[3*i + j]*chi);
          vel = oldVel_[index] + dt2/mass*PhysicalConstants::energyConvert * frc - dt2*chi*oldVel_[index];
            
          integrableObject->setVel(vel);

          if (integrableObject->isDirectional()) {

            // get and convert the torque to body frame

            Tb =  integrableObject->lab2Body(integrableObject->getTrq());

            //for(j = 0; j < 3; j++)
            //    ji[j] = oldJi_[3*i + j] + dt2 * (Tb[j] * PhysicalConstants::energyConvert - oldJi_[3*i+j]*chi);
            ji = oldJi_[index] + dt2*PhysicalConstants::energyConvert*Tb - dt2*chi *oldJi_[index];

            integrableObject->setJ(ji);
          }


          ++index;
        }
      }
    
      rattle_->constraintB();

      if (fabs(prevChi - chi) <= chiTolerance_)
        break;

    }

    flucQ_->moveB();

    integralOfChidt += dt2 * chi;
    currentSnapshot_->setChi(chi);
    currentSnapshot_->setIntegralOfChiDt(integralOfChidt);
  }

  void NVT::resetIntegrator() {
      currentSnapshot_->setChi(0.0);
      currentSnapshot_->setIntegralOfChiDt(0.0);
  }
  
  RealType NVT::calcConservedQuantity() {

    RealType chi = currentSnapshot_->getChi();
    RealType integralOfChidt = currentSnapshot_->getIntegralOfChiDt();
    RealType conservedQuantity;
    RealType fkBT;
    RealType Energy;
    RealType thermostat_kinetic;
    RealType thermostat_potential;
    
    fkBT = info_->getNdf() *PhysicalConstants::kB *targetTemp_;

    Energy = thermo.getTotalE();

    thermostat_kinetic = fkBT * tauThermostat_ * tauThermostat_ * chi * chi / (2.0 * PhysicalConstants::energyConvert);

    thermostat_potential = fkBT * integralOfChidt / PhysicalConstants::energyConvert;

    conservedQuantity = Energy + thermostat_kinetic + thermostat_potential;

    return conservedQuantity;
  }


}//end namespace OpenMD
Revision:	1715
Committed:	Tue May 22 21:55:31 2012 UTC (12 years, 11 months ago) by gezelter
File size:	9258 byte(s)
Log Message:	Adding more support structure for Fluctuating Charges.
#	User	Rev	Content
1	gezelter	507	/*
2	gezelter	246	* 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	gezelter	1390	* 1. Redistributions of source code must retain the above copyright
10	gezelter	246	* notice, this list of conditions and the following disclaimer.
11			*
12	gezelter	1390	* 2. Redistributions in binary form must reproduce the above copyright
13	gezelter	246	* 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	gezelter	1390	*
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, 24107 (2008).
39	gezelter	1665	* [4] Kuang & Gezelter, J. Chem. Phys. 133, 164101 (2010).
40			* [5] Vardeman, Stocker & Gezelter, J. Chem. Theory Comput. 7, 834 (2011).
41	gezelter	246	*/
42
43			#include "integrators/NVT.hpp"
44			#include "primitives/Molecule.hpp"
45	tim	3	#include "utils/simError.h"
46	gezelter	1390	#include "utils/PhysicalConstants.hpp"
47	gezelter	2
48	gezelter	1390	namespace OpenMD {
49	gezelter	2
50	gezelter	507	NVT::NVT(SimInfo* info) : VelocityVerletIntegrator(info), chiTolerance_ (1e-6), maxIterNum_(4) {
51	gezelter	2
52	gezelter	246	Globals* simParams = info_->getSimParams();
53	gezelter	2
54	tim	665	if (!simParams->getUseIntialExtendedSystemState()) {
55	gezelter	507	Snapshot* currSnapshot = info_->getSnapshotManager()->getCurrentSnapshot();
56			currSnapshot->setChi(0.0);
57			currSnapshot->setIntegralOfChiDt(0.0);
58	gezelter	246	}
59
60			if (!simParams->haveTargetTemp()) {
61	gezelter	507	sprintf(painCave.errMsg, "You can't use the NVT integrator without a targetTemp_!\n");
62			painCave.isFatal = 1;
63	gezelter	1390	painCave.severity = OPENMD_ERROR;
64	gezelter	507	simError();
65	gezelter	246	} else {
66	gezelter	507	targetTemp_ = simParams->getTargetTemp();
67	gezelter	246	}
68	gezelter	2
69	gezelter	1277	// We must set tauThermostat.
70	gezelter	2
71	gezelter	246	if (!simParams->haveTauThermostat()) {
72	gezelter	507	sprintf(painCave.errMsg, "If you use the constant temperature\n"
73	gezelter	1277	"\tintegrator, you must set tauThermostat.\n");
74	gezelter	2
75	gezelter	1390	painCave.severity = OPENMD_ERROR;
76	gezelter	507	painCave.isFatal = 1;
77			simError();
78	gezelter	246	} else {
79	gezelter	507	tauThermostat_ = simParams->getTauThermostat();
80	gezelter	2	}
81
82	gezelter	1715	updateSizes();
83	gezelter	507	}
84	gezelter	2
85	gezelter	1715	void NVT::doUpdateSizes() {
86	gezelter	246	oldVel_.resize(info_->getNIntegrableObjects());
87	gezelter	1715	oldJi_.resize(info_->getNIntegrableObjects());
88	gezelter	507	}
89			void NVT::moveA() {
90	gezelter	246	SimInfo::MoleculeIterator i;
91			Molecule::IntegrableObjectIterator j;
92			Molecule* mol;
93			StuntDouble* integrableObject;
94			Vector3d Tb;
95			Vector3d ji;
96	tim	963	RealType mass;
97	gezelter	246	Vector3d vel;
98			Vector3d pos;
99			Vector3d frc;
100	gezelter	2
101	tim	963	RealType chi = currentSnapshot_->getChi();
102			RealType integralOfChidt = currentSnapshot_->getIntegralOfChiDt();
103	gezelter	246
104			// We need the temperature at time = t for the chi update below:
105	gezelter	2
106	tim	963	RealType instTemp = thermo.getTemperature();
107	gezelter	2
108	gezelter	246	for (mol = info_->beginMolecule(i); mol != NULL; mol = info_->nextMolecule(i)) {
109	gezelter	507	for (integrableObject = mol->beginIntegrableObject(j); integrableObject != NULL;
110			integrableObject = mol->nextIntegrableObject(j)) {
111	gezelter	2
112	gezelter	246	vel = integrableObject->getVel();
113			pos = integrableObject->getPos();
114			frc = integrableObject->getFrc();
115	gezelter	2
116	gezelter	246	mass = integrableObject->getMass();
117	gezelter	2
118	gezelter	246	// velocity half step (use chi from previous step here):
119	gezelter	1390	//vel[j] += dt2 * ((frc[j] / mass ) * PhysicalConstants::energyConvert - vel[j]*chi);
120			vel += dt2 PhysicalConstants::energyConvert/massfrc - dt2chivel;
121	gezelter	246
122			// position whole step
123			//pos[j] += dt * vel[j];
124			pos += dt * vel;
125	gezelter	2
126	gezelter	246	integrableObject->setVel(vel);
127			integrableObject->setPos(pos);
128	gezelter	2
129	gezelter	246	if (integrableObject->isDirectional()) {
130	gezelter	2
131	gezelter	507	//convert the torque to body frame
132			Tb = integrableObject->lab2Body(integrableObject->getTrq());
133	gezelter	2
134	gezelter	507	// get the angular momentum, and propagate a half step
135	gezelter	2
136	gezelter	507	ji = integrableObject->getJ();
137	gezelter	2
138	gezelter	1390	//ji[j] += dt2 * (Tb[j] * PhysicalConstants::energyConvert - ji[j]*chi);
139			ji += dt2PhysicalConstants::energyConvertTb - dt2chi ji;
140	gezelter	1715	rotAlgo_->rotate(integrableObject, ji, dt);
141	gezelter	2
142	gezelter	507	integrableObject->setJ(ji);
143	gezelter	246	}
144	gezelter	507	}
145	gezelter	2
146			}
147	gezelter	246
148	gezelter	1715	flucQ_->moveA();
149			rattle_->constraintA();
150	gezelter	2
151	gezelter	246	// Finally, evolve chi a half step (just like a velocity) using
152			// temperature at time t, not time t+dt/2
153	gezelter	2
154	gezelter	246
155			chi += dt2 * (instTemp / targetTemp_ - 1.0) / (tauThermostat_ * tauThermostat_);
156			integralOfChidt += chi * dt2;
157	gezelter	2
158	gezelter	246	currentSnapshot_->setChi(chi);
159			currentSnapshot_->setIntegralOfChiDt(integralOfChidt);
160	gezelter	507	}
161	gezelter	2
162	gezelter	507	void NVT::moveB() {
163	gezelter	246	SimInfo::MoleculeIterator i;
164			Molecule::IntegrableObjectIterator j;
165			Molecule* mol;
166			StuntDouble* integrableObject;
167
168			Vector3d Tb;
169			Vector3d ji;
170			Vector3d vel;
171			Vector3d frc;
172	tim	963	RealType mass;
173			RealType instTemp;
174	gezelter	246	int index;
175			// Set things up for the iteration:
176	gezelter	2
177	tim	963	RealType chi = currentSnapshot_->getChi();
178			RealType oldChi = chi;
179			RealType prevChi;
180			RealType integralOfChidt = currentSnapshot_->getIntegralOfChiDt();
181	gezelter	2
182	gezelter	246	index = 0;
183			for (mol = info_->beginMolecule(i); mol != NULL; mol = info_->nextMolecule(i)) {
184	gezelter	507	for (integrableObject = mol->beginIntegrableObject(j); integrableObject != NULL;
185			integrableObject = mol->nextIntegrableObject(j)) {
186	gezelter	1710
187	gezelter	507	oldVel_[index] = integrableObject->getVel();
188	gezelter	1710
189			if (integrableObject->isDirectional())
190			oldJi_[index] = integrableObject->getJ();
191
192	gezelter	507	++index;
193	gezelter	1710	}
194	gezelter	2	}
195
196	gezelter	246	// do the iteration:
197	gezelter	2
198	gezelter	246	for(int k = 0; k < maxIterNum_; k++) {
199	gezelter	507	index = 0;
200			instTemp = thermo.getTemperature();
201	gezelter	2
202	gezelter	507	// evolve chi another half step using the temperature at t + dt/2
203	gezelter	2
204	gezelter	507	prevChi = chi;
205			chi = oldChi + dt2 * (instTemp / targetTemp_ - 1.0) / (tauThermostat_ * tauThermostat_);
206	gezelter	2
207	gezelter	507	for (mol = info_->beginMolecule(i); mol != NULL; mol = info_->nextMolecule(i)) {
208			for (integrableObject = mol->beginIntegrableObject(j); integrableObject != NULL;
209			integrableObject = mol->nextIntegrableObject(j)) {
210	gezelter	2
211	gezelter	507	frc = integrableObject->getFrc();
212			vel = integrableObject->getVel();
213	gezelter	2
214	gezelter	507	mass = integrableObject->getMass();
215	gezelter	2
216	gezelter	507	// velocity half step
217			//for(j = 0; j < 3; j++)
218	gezelter	1390	// vel[j] = oldVel_[3i+j] + dt2 ((frc[j] / mass ) * PhysicalConstants::energyConvert - oldVel_[3i + j]chi);
219			vel = oldVel_[index] + dt2/massPhysicalConstants::energyConvert frc - dt2chioldVel_[index];
220	gezelter	246
221	gezelter	507	integrableObject->setVel(vel);
222	gezelter	2
223	gezelter	507	if (integrableObject->isDirectional()) {
224	gezelter	2
225	gezelter	507	// get and convert the torque to body frame
226	gezelter	2
227	gezelter	507	Tb = integrableObject->lab2Body(integrableObject->getTrq());
228	gezelter	2
229	gezelter	507	//for(j = 0; j < 3; j++)
230	gezelter	1390	// ji[j] = oldJi_[3i + j] + dt2 (Tb[j] * PhysicalConstants::energyConvert - oldJi_[3i+j]chi);
231			ji = oldJi_[index] + dt2PhysicalConstants::energyConvertTb - dt2chi oldJi_[index];
232	gezelter	2
233	gezelter	507	integrableObject->setJ(ji);
234			}
235	gezelter	2
236
237	gezelter	507	++index;
238			}
239			}
240	gezelter	2
241	gezelter	1715	rattle_->constraintB();
242	gezelter	2
243	gezelter	507	if (fabs(prevChi - chi) <= chiTolerance_)
244			break;
245	gezelter	2
246	gezelter	246	}
247	gezelter	2
248	gezelter	1715	flucQ_->moveB();
249
250	gezelter	246	integralOfChidt += dt2 * chi;
251			currentSnapshot_->setChi(chi);
252			currentSnapshot_->setIntegralOfChiDt(integralOfChidt);
253	gezelter	507	}
254	gezelter	2
255	tim	546	void NVT::resetIntegrator() {
256			currentSnapshot_->setChi(0.0);
257			currentSnapshot_->setIntegralOfChiDt(0.0);
258			}
259
260	tim	963	RealType NVT::calcConservedQuantity() {
261	gezelter	2
262	tim	963	RealType chi = currentSnapshot_->getChi();
263			RealType integralOfChidt = currentSnapshot_->getIntegralOfChiDt();
264			RealType conservedQuantity;
265			RealType fkBT;
266			RealType Energy;
267			RealType thermostat_kinetic;
268			RealType thermostat_potential;
269	gezelter	246
270	gezelter	1390	fkBT = info_->getNdf() PhysicalConstants::kB targetTemp_;
271	gezelter	2
272	gezelter	246	Energy = thermo.getTotalE();
273	gezelter	2
274	gezelter	1390	thermostat_kinetic = fkBT * tauThermostat_ * tauThermostat_ * chi * chi / (2.0 * PhysicalConstants::energyConvert);
275	gezelter	2
276	gezelter	1390	thermostat_potential = fkBT * integralOfChidt / PhysicalConstants::energyConvert;
277	gezelter	2
278	gezelter	246	conservedQuantity = Energy + thermostat_kinetic + thermostat_potential;
279	gezelter	2
280	gezelter	246	return conservedQuantity;
281	gezelter	507	}
282	gezelter	2
283
284	gezelter	1390	}//end namespace OpenMD