ViewVC Help
View File | Revision Log | Show Annotations | View Changeset | Root Listing
root/group/trunk/OOPSE/libmdtools/NPTf.cpp
Revision: 576
Committed: Tue Jul 8 21:10:16 2003 UTC (21 years ago) by gezelter
File size: 6370 byte(s)
Log Message:
*** empty log message ***

File Contents

# User Rev Content
1 gezelter 576 #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 isotropic thermostating and barostating via the Melchionna
13     // modification of the Hoover algorithm:
14     //
15     // Melchionna, S., Ciccotti, G., and Holian, B. L., 1993,
16     // Molec. Phys., 78, 533.
17     //
18     // and
19     //
20     // Hoover, W. G., 1986, Phys. Rev. A, 34, 2499.
21    
22     NPTi::NPTi ( SimInfo *theInfo, ForceFields* the_ff):
23     Integrator( theInfo, the_ff )
24     {
25     int i;
26     chi = 0.0;
27     for(i = 0; i < 9; i++) eta[i] = 0.0;
28     have_tau_thermostat = 0;
29     have_tau_barostat = 0;
30     have_target_temp = 0;
31     have_target_pressure = 0;
32     }
33    
34     void NPTi::moveA() {
35    
36     int i,j,k;
37     int atomIndex, aMatIndex;
38     DirectionalAtom* dAtom;
39     double Tb[3];
40     double ji[3];
41     double rj[3];
42     double instaTemp, instaPress, instaVol;
43     double tt2, tb2;
44     double angle;
45    
46     tt2 = tauThermostat * tauThermostat;
47     tb2 = tauBarostat * tauBarostat;
48    
49     instaTemp = tStats->getTemperature();
50     instaPress = tStats->getPressure();
51     instaVol = tStats->getVolume();
52    
53     // first evolve chi a half step
54    
55     chi += dt2 * ( instaTemp / targetTemp - 1.0) / tt2;
56    
57     for (i = 0; i < 9; i++) {
58     eta[i] += dt2 * ( instaVol * (sigma[i] - targetPressure*identMat[i]))
59     / (NkBT*tb2));
60     }
61    
62     for( i=0; i<nAtoms; i++ ){
63     atomIndex = i * 3;
64     aMatIndex = i * 9;
65    
66     // velocity half step
67     for( j=atomIndex; j<(atomIndex+3); j++ )
68     vel[j] += dt2 * ((frc[j]/atoms[i]->getMass())*eConvert
69     - vel[j]*(chi+eta));
70    
71     // position whole step
72    
73     for( j=atomIndex; j<(atomIndex+3); j=j+3 ) {
74     rj[0] = pos[j];
75     rj[1] = pos[j+1];
76     rj[2] = pos[j+2];
77    
78     info->wrapVector(rj);
79    
80     pos[j] += dt * (vel[j] + eta*rj[0]);
81     pos[j+1] += dt * (vel[j+1] + eta*rj[1]);
82     pos[j+2] += dt * (vel[j+2] + eta*rj[2]);
83     }
84    
85     // Scale the box after all the positions have been moved:
86    
87     info->scaleBox(exp(dt*eta));
88    
89     if( atoms[i]->isDirectional() ){
90    
91     dAtom = (DirectionalAtom *)atoms[i];
92    
93     // get and convert the torque to body frame
94    
95     Tb[0] = dAtom->getTx();
96     Tb[1] = dAtom->getTy();
97     Tb[2] = dAtom->getTz();
98    
99     dAtom->lab2Body( Tb );
100    
101     // get the angular momentum, and propagate a half step
102    
103     ji[0] = dAtom->getJx();
104     ji[1] = dAtom->getJy();
105     ji[2] = dAtom->getJz();
106    
107     ji[0] += dt2 * (Tb[0] * eConvert - ji[0]*chi);
108     ji[1] += dt2 * (Tb[1] * eConvert - ji[1]*chi);
109     ji[2] += dt2 * (Tb[2] * eConvert - ji[2]*chi);
110    
111     // use the angular velocities to propagate the rotation matrix a
112     // full time step
113    
114     // rotate about the x-axis
115     angle = dt2 * ji[0] / dAtom->getIxx();
116     this->rotate( 1, 2, angle, ji, &Amat[aMatIndex] );
117    
118     // rotate about the y-axis
119     angle = dt2 * ji[1] / dAtom->getIyy();
120     this->rotate( 2, 0, angle, ji, &Amat[aMatIndex] );
121    
122     // rotate about the z-axis
123     angle = dt * ji[2] / dAtom->getIzz();
124     this->rotate( 0, 1, angle, ji, &Amat[aMatIndex] );
125    
126     // rotate about the y-axis
127     angle = dt2 * ji[1] / dAtom->getIyy();
128     this->rotate( 2, 0, angle, ji, &Amat[aMatIndex] );
129    
130     // rotate about the x-axis
131     angle = dt2 * ji[0] / dAtom->getIxx();
132     this->rotate( 1, 2, angle, ji, &Amat[aMatIndex] );
133    
134     dAtom->setJx( ji[0] );
135     dAtom->setJy( ji[1] );
136     dAtom->setJz( ji[2] );
137     }
138    
139     }
140     }
141    
142     void NPTi::moveB( void ){
143     int i,j,k;
144     int atomIndex;
145     DirectionalAtom* dAtom;
146     double Tb[3];
147     double ji[3];
148     double instaTemp, instaPress, instaVol;
149     double tt2, tb2;
150    
151     tt2 = tauThermostat * tauThermostat;
152     tb2 = tauBarostat * tauBarostat;
153    
154     instaTemp = tStats->getTemperature();
155     instaPress = tStats->getPressure();
156     instaVol = tStats->getVolume();
157    
158     chi += dt2 * ( instaTemp / targetTemp - 1.0) / tt2;
159     eta += dt2 * ( instaVol * (instaPress - targetPressure) / (NkBT*tb2));
160    
161     for( i=0; i<nAtoms; i++ ){
162     atomIndex = i * 3;
163    
164     // velocity half step
165     for( j=atomIndex; j<(atomIndex+3); j++ )
166     for( j=atomIndex; j<(atomIndex+3); j++ )
167     vel[j] += dt2 * ((frc[j]/atoms[i]->getMass())*eConvert
168     - vel[j]*(chi+eta));
169    
170     if( atoms[i]->isDirectional() ){
171    
172     dAtom = (DirectionalAtom *)atoms[i];
173    
174     // get and convert the torque to body frame
175    
176     Tb[0] = dAtom->getTx();
177     Tb[1] = dAtom->getTy();
178     Tb[2] = dAtom->getTz();
179    
180     dAtom->lab2Body( Tb );
181    
182     // get the angular momentum, and complete the angular momentum
183     // half step
184    
185     ji[0] = dAtom->getJx();
186     ji[1] = dAtom->getJy();
187     ji[2] = dAtom->getJz();
188    
189     ji[0] += dt2 * (Tb[0] * eConvert - ji[0]*chi);
190     ji[1] += dt2 * (Tb[1] * eConvert - ji[1]*chi);
191     ji[2] += dt2 * (Tb[2] * eConvert - ji[2]*chi);
192    
193     dAtom->setJx( ji[0] );
194     dAtom->setJy( ji[1] );
195     dAtom->setJz( ji[2] );
196     }
197     }
198     }
199    
200     int NPTi::readyCheck() {
201    
202     // First check to see if we have a target temperature.
203     // Not having one is fatal.
204    
205     if (!have_target_temp) {
206     sprintf( painCave.errMsg,
207     "NPTi error: You can't use the NPTi integrator\n"
208     " without a targetTemp!\n"
209     );
210     painCave.isFatal = 1;
211     simError();
212     return -1;
213     }
214    
215     if (!have_target_pressure) {
216     sprintf( painCave.errMsg,
217     "NPTi error: You can't use the NPTi integrator\n"
218     " without a targetPressure!\n"
219     );
220     painCave.isFatal = 1;
221     simError();
222     return -1;
223     }
224    
225     // We must set tauThermostat.
226    
227     if (!have_tau_thermostat) {
228     sprintf( painCave.errMsg,
229     "NPTi error: If you use the NPTi\n"
230     " integrator, you must set tauThermostat.\n");
231     painCave.isFatal = 1;
232     simError();
233     return -1;
234     }
235    
236     // We must set tauBarostat.
237    
238     if (!have_tau_barostat) {
239     sprintf( painCave.errMsg,
240     "NPTi error: If you use the NPTi\n"
241     " integrator, you must set tauBarostat.\n");
242     painCave.isFatal = 1;
243     simError();
244     return -1;
245     }
246    
247     // We need NkBT a lot, so just set it here:
248    
249     NkBT = (double)info->ndf * kB * targetTemp;
250    
251     return 1;
252     }