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root/group/trunk/OOPSE/libmdtools/NVT.cpp
Revision: 763
Committed: Mon Sep 15 16:52:02 2003 UTC (20 years, 9 months ago) by tim
File size: 5994 byte(s)
Log Message:
add conserved quantity to statWriter
fix bug of vector wrapping at NPTi

File Contents

# User Rev Content
1 gezelter 560 #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 mmeineke 561 #include "simError.h"
10    
11    
12 gezelter 560 // Basic thermostating via Hoover, Phys.Rev.A, 1985, Vol. 31 (5) 1695-1697
13    
14 tim 645 template<typename T> NVT<T>::NVT ( SimInfo *theInfo, ForceFields* the_ff):
15     T( theInfo, the_ff )
16 mmeineke 561 {
17 gezelter 565 chi = 0.0;
18 gezelter 560 have_tau_thermostat = 0;
19     have_target_temp = 0;
20 tim 763 have_chi_tolerance = 0;
21     integralOfChidt = 0.0;
22    
23     oldVel = new double[3*nAtoms];
24     oldJi = new double[3*nAtoms];
25 gezelter 560 }
26    
27 tim 763 template<typename T> NVT<T>::~NVT() {
28     delete[] oldVel;
29     delete[] oldJi;
30     }
31    
32 tim 645 template<typename T> void NVT<T>::moveA() {
33 gezelter 560
34 gezelter 600 int i, j;
35 gezelter 560 DirectionalAtom* dAtom;
36 gezelter 600 double Tb[3], ji[3];
37     double A[3][3], I[3][3];
38     double angle, mass;
39     double vel[3], pos[3], frc[3];
40    
41 gezelter 565 double instTemp;
42 gezelter 560
43 tim 763 // We need the temperature at time = t for the chi update below:
44    
45 gezelter 565 instTemp = tStats->getTemperature();
46    
47 gezelter 560 for( i=0; i<nAtoms; i++ ){
48    
49 gezelter 600 atoms[i]->getVel( vel );
50     atoms[i]->getPos( pos );
51     atoms[i]->getFrc( frc );
52    
53     mass = atoms[i]->getMass();
54    
55     for (j=0; j < 3; j++) {
56 tim 763 // velocity half step (use chi from previous step here):
57 gezelter 600 vel[j] += dt2 * ((frc[j] / mass ) * eConvert - vel[j]*chi);
58     // position whole step
59 gezelter 560 pos[j] += dt * vel[j];
60 gezelter 600 }
61 gezelter 560
62 gezelter 600 atoms[i]->setVel( vel );
63     atoms[i]->setPos( pos );
64 gezelter 560
65     if( atoms[i]->isDirectional() ){
66    
67     dAtom = (DirectionalAtom *)atoms[i];
68    
69     // get and convert the torque to body frame
70    
71 gezelter 600 dAtom->getTrq( Tb );
72 gezelter 560 dAtom->lab2Body( Tb );
73    
74     // get the angular momentum, and propagate a half step
75    
76 gezelter 600 dAtom->getJ( ji );
77    
78     for (j=0; j < 3; j++)
79     ji[j] += dt2 * (Tb[j] * eConvert - ji[j]*chi);
80 gezelter 560
81     // use the angular velocities to propagate the rotation matrix a
82     // full time step
83 gezelter 600
84     dAtom->getA(A);
85     dAtom->getI(I);
86    
87 gezelter 560 // rotate about the x-axis
88 gezelter 600 angle = dt2 * ji[0] / I[0][0];
89     this->rotate( 1, 2, angle, ji, A );
90    
91 gezelter 560 // rotate about the y-axis
92 gezelter 600 angle = dt2 * ji[1] / I[1][1];
93     this->rotate( 2, 0, angle, ji, A );
94 gezelter 560
95     // rotate about the z-axis
96 gezelter 600 angle = dt * ji[2] / I[2][2];
97     this->rotate( 0, 1, angle, ji, A);
98 gezelter 560
99     // rotate about the y-axis
100 gezelter 600 angle = dt2 * ji[1] / I[1][1];
101     this->rotate( 2, 0, angle, ji, A );
102 gezelter 560
103     // rotate about the x-axis
104 gezelter 600 angle = dt2 * ji[0] / I[0][0];
105     this->rotate( 1, 2, angle, ji, A );
106 gezelter 560
107 gezelter 600 dAtom->setJ( ji );
108     dAtom->setA( A );
109     }
110 gezelter 560 }
111 tim 763
112     // Finally, evolve chi a half step (just like a velocity) using
113     // temperature at time t, not time t+dt/2
114    
115     chi += dt2 * ( instTemp / targetTemp - 1.0) / (tauThermostat*tauThermostat);
116     integralOfChidt += chi*dt2;
117    
118 gezelter 560 }
119    
120 tim 645 template<typename T> void NVT<T>::moveB( void ){
121 tim 763 int i, j, k;
122 gezelter 560 DirectionalAtom* dAtom;
123 gezelter 600 double Tb[3], ji[3];
124     double vel[3], frc[3];
125     double mass;
126 tim 763 double instTemp;
127     double oldChi, prevChi;
128 gezelter 600
129 tim 763 // Set things up for the iteration:
130    
131     oldChi = chi;
132    
133 gezelter 560 for( i=0; i<nAtoms; i++ ){
134 gezelter 600
135     atoms[i]->getVel( vel );
136    
137 tim 763 for (j=0; j < 3; j++)
138     oldVel[3*i + j] = vel[j];
139 gezelter 600
140 gezelter 560 if( atoms[i]->isDirectional() ){
141 gezelter 600
142 gezelter 560 dAtom = (DirectionalAtom *)atoms[i];
143 gezelter 600
144 tim 763 dAtom->getJ( ji );
145 gezelter 600
146 tim 763 for (j=0; j < 3; j++)
147     oldJi[3*i + j] = ji[j];
148 gezelter 600
149 tim 763 }
150     }
151 gezelter 600
152 tim 763 // do the iteration:
153 gezelter 600
154 tim 763 for (k=0; k < 4; k++) {
155    
156     instTemp = tStats->getTemperature();
157    
158     // evolve chi another half step using the temperature at t + dt/2
159    
160     prevChi = chi;
161     chi = oldChi + dt2 * ( instTemp / targetTemp - 1.0) /
162     (tauThermostat*tauThermostat);
163    
164     for( i=0; i<nAtoms; i++ ){
165    
166     atoms[i]->getFrc( frc );
167     atoms[i]->getVel(vel);
168    
169     mass = atoms[i]->getMass();
170    
171     // velocity half step
172 gezelter 600 for (j=0; j < 3; j++)
173 tim 763 vel[j] = oldVel[3*i+j] + dt2 * ((frc[j] / mass ) * eConvert - oldVel[3*i + j]*chi);
174 gezelter 560
175 tim 763 atoms[i]->setVel( vel );
176    
177     if( atoms[i]->isDirectional() ){
178    
179     dAtom = (DirectionalAtom *)atoms[i];
180    
181     // get and convert the torque to body frame
182    
183     dAtom->getTrq( Tb );
184     dAtom->lab2Body( Tb );
185    
186     for (j=0; j < 3; j++)
187     ji[j] = oldJi[3*i + j] + dt2 * (Tb[j] * eConvert - oldJi[3*i+j]*chi);
188    
189     dAtom->setJ( ji );
190     }
191     }
192 gezelter 600
193 tim 763 if (fabs(prevChi - chi) <= chiTolerance) break;
194 gezelter 560 }
195 tim 763
196     integralOfChidt += dt2*chi;
197 gezelter 560 }
198    
199 mmeineke 746 template<typename T> void NVT<T>::resetIntegrator( void ){
200    
201     chi = 0.0;
202 tim 763 integralOfChidt = 0.0;
203 mmeineke 746 }
204    
205 tim 645 template<typename T> int NVT<T>::readyCheck() {
206 tim 658
207     //check parent's readyCheck() first
208     if (T::readyCheck() == -1)
209     return -1;
210    
211 gezelter 560 // First check to see if we have a target temperature.
212     // Not having one is fatal.
213    
214     if (!have_target_temp) {
215     sprintf( painCave.errMsg,
216     "NVT error: You can't use the NVT integrator without a targetTemp!\n"
217     );
218     painCave.isFatal = 1;
219     simError();
220     return -1;
221     }
222 gezelter 565
223     // We must set tauThermostat.
224    
225     if (!have_tau_thermostat) {
226 gezelter 560 sprintf( painCave.errMsg,
227 gezelter 565 "NVT error: If you use the constant temperature\n"
228     " integrator, you must set tauThermostat.\n");
229 gezelter 560 painCave.isFatal = 1;
230     simError();
231     return -1;
232 gezelter 565 }
233 tim 763
234     if (!have_chi_tolerance) {
235     sprintf( painCave.errMsg,
236     "NVT warning: setting chi tolerance to 1e-6\n");
237     chiTolerance = 1e-6;
238     have_chi_tolerance = 1;
239     painCave.isFatal = 0;
240     simError();
241     }
242    
243     return 1;
244    
245 gezelter 560 }
246 tim 763
247     template<typename T> double NVT<T>::getConservedQuantity(void){
248    
249     double conservedQuantity;
250     double E_NVT;
251    
252     //HNVE
253     conservedQuantity = tStats->getTotalE();
254     //HNVE
255    
256     E_NVT = (info->getNDF() * kB * targetTemp *
257     (integralOfChidt + tauThermostat * tauThermostat * chi * chi / 2.0 )) / eConvert;
258    
259     conservedQuantity += E_NVT;
260    
261     //cerr << info->getTime() << "\t" << chi << "\t" << integralOfChidt << "\t" << E_NVT << endl;
262    
263     return conservedQuantity;
264     }