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root/group/trunk/OOPSE/libmdtools/NVT.cpp
Revision: 837
Committed: Wed Oct 29 00:19:10 2003 UTC (20 years, 8 months ago) by tim
File size: 6286 byte(s)
Log Message:
add chi and eta to the comment line of dump file.

File Contents

# Content
1 #include "Atom.hpp"
2 #include "SRI.hpp"
3 #include "AbstractClasses.hpp"
4 #include "SimInfo.hpp"
5 #include "ForceFields.hpp"
6 #include "Thermo.hpp"
7 #include "ReadWrite.hpp"
8 #include "Integrator.hpp"
9 #include "simError.h"
10
11
12 // Basic thermostating via Hoover, Phys.Rev.A, 1985, Vol. 31 (5) 1695-1697
13
14 template<typename T> NVT<T>::NVT ( SimInfo *theInfo, ForceFields* the_ff):
15 T( theInfo, the_ff )
16 {
17 GenericData* data;
18 DoubleData * chiValue;
19 DoubleData * integralOfChidtValue;
20
21 chiValue = NULL;
22 integralOfChidtValue = NULL;
23
24 chi = 0.0;
25 have_tau_thermostat = 0;
26 have_target_temp = 0;
27 have_chi_tolerance = 0;
28 integralOfChidt = 0.0;
29
30 // retrieve chi and integralOfChidt from simInfo
31 data = info->getProperty(CHIVALUE_ID);
32 if(data){
33 chiValue = dynamic_cast<DoubleData*>(data);
34 }
35
36 data = info->getProperty(INTEGRALOFCHIDT_ID);
37 if(data){
38 integralOfChidtValue = dynamic_cast<DoubleData*>(data);
39 }
40
41 // chi and integralOfChidt should appear by pair
42 if(chiValue && integralOfChidtValue){
43 chi = chiValue->getData();
44 integralOfChidt = integralOfChidtValue->getData();
45 }
46
47 oldVel = new double[3*nAtoms];
48 oldJi = new double[3*nAtoms];
49 }
50
51 template<typename T> NVT<T>::~NVT() {
52 delete[] oldVel;
53 delete[] oldJi;
54 }
55
56 template<typename T> void NVT<T>::moveA() {
57
58 int i, j;
59 DirectionalAtom* dAtom;
60 double Tb[3], ji[3];
61 double mass;
62 double vel[3], pos[3], frc[3];
63
64 double instTemp;
65
66 // We need the temperature at time = t for the chi update below:
67
68 instTemp = tStats->getTemperature();
69
70 for( i=0; i<nAtoms; i++ ){
71
72 atoms[i]->getVel( vel );
73 atoms[i]->getPos( pos );
74 atoms[i]->getFrc( frc );
75
76 mass = atoms[i]->getMass();
77
78 for (j=0; j < 3; j++) {
79 // velocity half step (use chi from previous step here):
80 vel[j] += dt2 * ((frc[j] / mass ) * eConvert - vel[j]*chi);
81 // position whole step
82 pos[j] += dt * vel[j];
83 }
84
85 atoms[i]->setVel( vel );
86 atoms[i]->setPos( pos );
87
88 if( atoms[i]->isDirectional() ){
89
90 dAtom = (DirectionalAtom *)atoms[i];
91
92 // get and convert the torque to body frame
93
94 dAtom->getTrq( Tb );
95 dAtom->lab2Body( Tb );
96
97 // get the angular momentum, and propagate a half step
98
99 dAtom->getJ( ji );
100
101 for (j=0; j < 3; j++)
102 ji[j] += dt2 * (Tb[j] * eConvert - ji[j]*chi);
103
104 this->rotationPropagation( dAtom, ji );
105
106 dAtom->setJ( ji );
107 }
108 }
109
110 if (nConstrained){
111 constrainA();
112 }
113
114 // Finally, evolve chi a half step (just like a velocity) using
115 // temperature at time t, not time t+dt/2
116
117 chi += dt2 * ( instTemp / targetTemp - 1.0) / (tauThermostat*tauThermostat);
118 integralOfChidt += chi*dt2;
119
120 }
121
122 template<typename T> void NVT<T>::moveB( void ){
123 int i, j, k;
124 DirectionalAtom* dAtom;
125 double Tb[3], ji[3];
126 double vel[3], frc[3];
127 double mass;
128 double instTemp;
129 double oldChi, prevChi;
130
131 // Set things up for the iteration:
132
133 oldChi = chi;
134
135 for( i=0; i<nAtoms; i++ ){
136
137 atoms[i]->getVel( vel );
138
139 for (j=0; j < 3; j++)
140 oldVel[3*i + j] = vel[j];
141
142 if( atoms[i]->isDirectional() ){
143
144 dAtom = (DirectionalAtom *)atoms[i];
145
146 dAtom->getJ( ji );
147
148 for (j=0; j < 3; j++)
149 oldJi[3*i + j] = ji[j];
150
151 }
152 }
153
154 // do the iteration:
155
156 for (k=0; k < 4; k++) {
157
158 instTemp = tStats->getTemperature();
159
160 // evolve chi another half step using the temperature at t + dt/2
161
162 prevChi = chi;
163 chi = oldChi + dt2 * ( instTemp / targetTemp - 1.0) /
164 (tauThermostat*tauThermostat);
165
166 for( i=0; i<nAtoms; i++ ){
167
168 atoms[i]->getFrc( frc );
169 atoms[i]->getVel(vel);
170
171 mass = atoms[i]->getMass();
172
173 // velocity half step
174 for (j=0; j < 3; j++)
175 vel[j] = oldVel[3*i+j] + dt2 * ((frc[j] / mass ) * eConvert - oldVel[3*i + j]*chi);
176
177 atoms[i]->setVel( vel );
178
179 if( atoms[i]->isDirectional() ){
180
181 dAtom = (DirectionalAtom *)atoms[i];
182
183 // get and convert the torque to body frame
184
185 dAtom->getTrq( Tb );
186 dAtom->lab2Body( Tb );
187
188 for (j=0; j < 3; j++)
189 ji[j] = oldJi[3*i + j] + dt2 * (Tb[j] * eConvert - oldJi[3*i+j]*chi);
190
191 dAtom->setJ( ji );
192 }
193 }
194
195 if (nConstrained){
196 constrainB();
197 }
198
199 if (fabs(prevChi - chi) <= chiTolerance) break;
200 }
201
202 integralOfChidt += dt2*chi;
203 }
204
205 template<typename T> void NVT<T>::resetIntegrator( void ){
206
207 chi = 0.0;
208 integralOfChidt = 0.0;
209 }
210
211 template<typename T> int NVT<T>::readyCheck() {
212
213 //check parent's readyCheck() first
214 if (T::readyCheck() == -1)
215 return -1;
216
217 // First check to see if we have a target temperature.
218 // Not having one is fatal.
219
220 if (!have_target_temp) {
221 sprintf( painCave.errMsg,
222 "NVT error: You can't use the NVT integrator without a targetTemp!\n"
223 );
224 painCave.isFatal = 1;
225 simError();
226 return -1;
227 }
228
229 // We must set tauThermostat.
230
231 if (!have_tau_thermostat) {
232 sprintf( painCave.errMsg,
233 "NVT error: If you use the constant temperature\n"
234 " integrator, you must set tauThermostat.\n");
235 painCave.isFatal = 1;
236 simError();
237 return -1;
238 }
239
240 if (!have_chi_tolerance) {
241 sprintf( painCave.errMsg,
242 "NVT warning: setting chi tolerance to 1e-6\n");
243 chiTolerance = 1e-6;
244 have_chi_tolerance = 1;
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->getNDF() ) * 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 cerr << info->getTime() << "\t" << Energy << "\t" << thermostat_kinetic <<
273 "\t" << thermostat_potential << "\t" << conservedQuantity << endl;
274
275 return conservedQuantity;
276 }
277
278 template<typename T> string NVT<T>::getAdditionalParameters(void){
279 string parameters;
280 const int BUFFERSIZE = 2000; // size of the read buffer
281 char buffer[BUFFERSIZE];
282
283 sprintf(buffer,"\t%g\t%g;", chi, integralOfChidt);
284 parameters += buffer;
285
286 return parameters;
287 }