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root/group/trunk/OOPSE/libmdtools/NVT.cpp
Revision: 1268
Committed: Fri Jun 11 17:16:21 2004 UTC (20 years ago) by tim
File size: 6708 byte(s)
Log Message:
roll in progress

File Contents

# Content
1 #include <math.h>
2
3 #include "Atom.hpp"
4 #include "SRI.hpp"
5 #include "AbstractClasses.hpp"
6 #include "SimInfo.hpp"
7 #include "ForceFields.hpp"
8 #include "Thermo.hpp"
9 #include "ReadWrite.hpp"
10 #include "Integrator.hpp"
11 #include "simError.h"
12
13
14 // Basic thermostating via Hoover, Phys.Rev.A, 1985, Vol. 31 (5) 1695-1697
15
16 template<typename T> NVT<T>::NVT ( SimInfo *theInfo, ForceFields* the_ff):
17 T( theInfo, the_ff )
18 {
19 GenericData* data;
20 DoubleData * chiValue;
21 DoubleData * integralOfChidtValue;
22
23 chiValue = NULL;
24 integralOfChidtValue = NULL;
25
26 chi = 0.0;
27 have_tau_thermostat = 0;
28 have_target_temp = 0;
29 have_chi_tolerance = 0;
30 integralOfChidt = 0.0;
31
32
33 if( theInfo->useInitXSstate ){
34
35 // retrieve chi and integralOfChidt from simInfo
36 data = info->getProperty(CHIVALUE_ID);
37 if(data){
38 chiValue = dynamic_cast<DoubleData*>(data);
39 }
40
41 data = info->getProperty(INTEGRALOFCHIDT_ID);
42 if(data){
43 integralOfChidtValue = dynamic_cast<DoubleData*>(data);
44 }
45
46 // chi and integralOfChidt should appear by pair
47 if(chiValue && integralOfChidtValue){
48 chi = chiValue->getData();
49 integralOfChidt = integralOfChidtValue->getData();
50 }
51 }
52
53 oldVel = new double[3*integrableObjects.size()];
54 oldJi = new double[3*integrableObjects.size()];
55 }
56
57 template<typename T> NVT<T>::~NVT() {
58 delete[] oldVel;
59 delete[] oldJi;
60 }
61
62 template<typename T> void NVT<T>::moveA() {
63
64 int i, j;
65 DirectionalAtom* dAtom;
66 double Tb[3], ji[3];
67 double mass;
68 double vel[3], pos[3], frc[3];
69
70 double instTemp;
71
72 // We need the temperature at time = t for the chi update below:
73
74 instTemp = tStats->getTemperature();
75
76 for( i=0; i < integrableObjects.size(); i++ ){
77
78 integrableObjects[i]->getVel( vel );
79 integrableObjects[i]->getPos( pos );
80 integrableObjects[i]->getFrc( frc );
81
82 mass = integrableObjects[i]->getMass();
83
84 for (j=0; j < 3; j++) {
85 // velocity half step (use chi from previous step here):
86 vel[j] += dt2 * ((frc[j] / mass ) * eConvert - vel[j]*chi);
87 // position whole step
88 pos[j] += dt * vel[j];
89 }
90
91 integrableObjects[i]->setVel( vel );
92 integrableObjects[i]->setPos( pos );
93
94 if( integrableObjects[i]->isDirectional() ){
95
96 // get and convert the torque to body frame
97
98 integrableObjects[i]->getTrq( Tb );
99 integrableObjects[i]->lab2Body( Tb );
100
101 // get the angular momentum, and propagate a half step
102
103 integrableObjects[i]->getJ( ji );
104
105 for (j=0; j < 3; j++)
106 ji[j] += dt2 * (Tb[j] * eConvert - ji[j]*chi);
107
108 this->rotationPropagation( integrableObjects[i], ji );
109
110 integrableObjects[i]->setJ( ji );
111 }
112 }
113
114 consFramework->doConstrainA();
115
116 // Finally, evolve chi a half step (just like a velocity) using
117 // temperature at time t, not time t+dt/2
118
119 //std::cerr << "targetTemp = " << targetTemp << " instTemp = " << instTemp << " tauThermostat = " << tauThermostat << " integral of Chi = " << integralOfChidt << "\n";
120
121 chi += dt2 * ( instTemp / targetTemp - 1.0) / (tauThermostat*tauThermostat);
122 integralOfChidt += chi*dt2;
123
124 }
125
126 template<typename T> void NVT<T>::moveB( void ){
127 int i, j, k;
128 double Tb[3], ji[3];
129 double vel[3], frc[3];
130 double mass;
131 double instTemp;
132 double oldChi, prevChi;
133
134 // Set things up for the iteration:
135
136 oldChi = chi;
137
138 for( i=0; i < integrableObjects.size(); i++ ){
139
140 integrableObjects[i]->getVel( vel );
141
142 for (j=0; j < 3; j++)
143 oldVel[3*i + j] = vel[j];
144
145 if( integrableObjects[i]->isDirectional() ){
146
147 integrableObjects[i]->getJ( ji );
148
149 for (j=0; j < 3; j++)
150 oldJi[3*i + j] = ji[j];
151
152 }
153 }
154
155 // do the iteration:
156
157 for (k=0; k < 4; k++) {
158
159 instTemp = tStats->getTemperature();
160
161 // evolve chi another half step using the temperature at t + dt/2
162
163 prevChi = chi;
164 chi = oldChi + dt2 * ( instTemp / targetTemp - 1.0) /
165 (tauThermostat*tauThermostat);
166
167 for( i=0; i < integrableObjects.size(); i++ ){
168
169 integrableObjects[i]->getFrc( frc );
170 integrableObjects[i]->getVel(vel);
171
172 mass = integrableObjects[i]->getMass();
173
174 // velocity half step
175 for (j=0; j < 3; j++)
176 vel[j] = oldVel[3*i+j] + dt2 * ((frc[j] / mass ) * eConvert - oldVel[3*i + j]*chi);
177
178 integrableObjects[i]->setVel( vel );
179
180 if( integrableObjects[i]->isDirectional() ){
181
182 // get and convert the torque to body frame
183
184 integrableObjects[i]->getTrq( Tb );
185 integrableObjects[i]->lab2Body( Tb );
186
187 for (j=0; j < 3; j++)
188 ji[j] = oldJi[3*i + j] + dt2 * (Tb[j] * eConvert - oldJi[3*i+j]*chi);
189
190 integrableObjects[i]->setJ( ji );
191 }
192 }
193
194 consFramework->doConstrainB();
195
196 if (fabs(prevChi - chi) <= chiTolerance) break;
197 }
198
199 integralOfChidt += dt2*chi;
200 }
201
202 template<typename T> void NVT<T>::resetIntegrator( void ){
203
204 chi = 0.0;
205 integralOfChidt = 0.0;
206 }
207
208 template<typename T> int NVT<T>::readyCheck() {
209
210 //check parent's readyCheck() first
211 if (T::readyCheck() == -1)
212 return -1;
213
214 // First check to see if we have a target temperature.
215 // Not having one is fatal.
216
217 if (!have_target_temp) {
218 sprintf( painCave.errMsg,
219 "You can't use the NVT integrator without a targetTemp!\n"
220 );
221 painCave.isFatal = 1;
222 painCave.severity = OOPSE_ERROR;
223 simError();
224 return -1;
225 }
226
227 // We must set tauThermostat.
228
229 if (!have_tau_thermostat) {
230 sprintf( painCave.errMsg,
231 "If you use the constant temperature\n"
232 "\tintegrator, you must set tauThermostat.\n");
233 painCave.severity = OOPSE_ERROR;
234 painCave.isFatal = 1;
235 simError();
236 return -1;
237 }
238
239 if (!have_chi_tolerance) {
240 sprintf( painCave.errMsg,
241 "In NVT integrator: setting chi tolerance to 1e-6\n");
242 chiTolerance = 1e-6;
243 have_chi_tolerance = 1;
244 painCave.severity = OOPSE_INFO;
245 painCave.isFatal = 0;
246 simError();
247 }
248
249 return 1;
250
251 }
252
253 template<typename T> double NVT<T>::getConservedQuantity(void){
254
255 double conservedQuantity;
256 double fkBT;
257 double Energy;
258 double thermostat_kinetic;
259 double thermostat_potential;
260
261 fkBT = (double)(info->ndf) * kB * targetTemp;
262
263 Energy = tStats->getTotalE();
264
265 thermostat_kinetic = fkBT* tauThermostat * tauThermostat * chi * chi /
266 (2.0 * eConvert);
267
268 thermostat_potential = fkBT * integralOfChidt / eConvert;
269
270 conservedQuantity = Energy + thermostat_kinetic + thermostat_potential;
271
272 return conservedQuantity;
273 }
274
275 template<typename T> string NVT<T>::getAdditionalParameters(void){
276 string parameters;
277 const int BUFFERSIZE = 2000; // size of the read buffer
278 char buffer[BUFFERSIZE];
279
280 sprintf(buffer,"\t%G\t%G;", chi, integralOfChidt);
281 parameters += buffer;
282
283 return parameters;
284 }