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root/group/trunk/OOPSE/libmdtools/Thermo.cpp
Revision: 483
Committed: Wed Apr 9 04:06:43 2003 UTC (21 years, 3 months ago) by gezelter
File size: 8045 byte(s)
Log Message:
fixes for NPT and NVT

File Contents

# User Rev Content
1 mmeineke 377 #include <cmath>
2     #include <iostream>
3     using namespace std;
4    
5     #ifdef IS_MPI
6     #include <mpi.h>
7     #endif //is_mpi
8    
9     #include "Thermo.hpp"
10     #include "SRI.hpp"
11     #include "Integrator.hpp"
12 chuckv 438 #include "simError.h"
13 mmeineke 402
14     #ifdef IS_MPI
15 chuckv 401 #define __C
16 mmeineke 402 #include "mpiSimulation.hpp"
17     #endif // is_mpi
18 mmeineke 377
19 mmeineke 402
20 mmeineke 377 #define BASE_SEED 123456789
21    
22     Thermo::Thermo( SimInfo* the_entry_plug ) {
23     entry_plug = the_entry_plug;
24     int baseSeed = BASE_SEED;
25    
26     gaussStream = new gaussianSPRNG( baseSeed );
27     }
28    
29     Thermo::~Thermo(){
30     delete gaussStream;
31     }
32    
33     double Thermo::getKinetic(){
34    
35     const double e_convert = 4.184E-4; // convert kcal/mol -> (amu A^2)/fs^2
36     double vx2, vy2, vz2;
37     double kinetic, v_sqr;
38     int kl;
39     double jx2, jy2, jz2; // the square of the angular momentums
40    
41     DirectionalAtom *dAtom;
42    
43     int n_atoms;
44     double kinetic_global;
45     Atom** atoms;
46    
47    
48     n_atoms = entry_plug->n_atoms;
49     atoms = entry_plug->atoms;
50    
51     kinetic = 0.0;
52     kinetic_global = 0.0;
53     for( kl=0; kl < n_atoms; kl++ ){
54    
55     vx2 = atoms[kl]->get_vx() * atoms[kl]->get_vx();
56     vy2 = atoms[kl]->get_vy() * atoms[kl]->get_vy();
57     vz2 = atoms[kl]->get_vz() * atoms[kl]->get_vz();
58    
59     v_sqr = vx2 + vy2 + vz2;
60     kinetic += atoms[kl]->getMass() * v_sqr;
61    
62     if( atoms[kl]->isDirectional() ){
63    
64     dAtom = (DirectionalAtom *)atoms[kl];
65    
66     jx2 = dAtom->getJx() * dAtom->getJx();
67     jy2 = dAtom->getJy() * dAtom->getJy();
68     jz2 = dAtom->getJz() * dAtom->getJz();
69    
70     kinetic += (jx2 / dAtom->getIxx()) + (jy2 / dAtom->getIyy())
71     + (jz2 / dAtom->getIzz());
72     }
73     }
74     #ifdef IS_MPI
75 mmeineke 447 MPI_Allreduce(&kinetic,&kinetic_global,1,MPI_DOUBLE,
76     MPI_SUM, MPI_COMM_WORLD);
77 mmeineke 377 kinetic = kinetic_global;
78     #endif //is_mpi
79    
80     kinetic = kinetic * 0.5 / e_convert;
81    
82     return kinetic;
83     }
84    
85     double Thermo::getPotential(){
86    
87 chuckv 401 double potential_local;
88 mmeineke 377 double potential;
89     int el, nSRI;
90 mmeineke 428 Molecule* molecules;
91 mmeineke 377
92 mmeineke 428 molecules = entry_plug->molecules;
93 mmeineke 377 nSRI = entry_plug->n_SRI;
94    
95 chuckv 401 potential_local = 0.0;
96 chuckv 438 potential = 0.0;
97 chuckv 401 potential_local += entry_plug->lrPot;
98 mmeineke 377
99 mmeineke 423 for( el=0; el<entry_plug->n_mol; el++ ){
100 mmeineke 428 potential_local += molecules[el].getPotential();
101 mmeineke 377 }
102    
103     // Get total potential for entire system from MPI.
104     #ifdef IS_MPI
105 mmeineke 447 MPI_Allreduce(&potential_local,&potential,1,MPI_DOUBLE,
106     MPI_SUM, MPI_COMM_WORLD);
107 chuckv 401 #else
108     potential = potential_local;
109 mmeineke 377 #endif // is_mpi
110    
111 chuckv 438 #ifdef IS_MPI
112     /*
113     std::cerr << "node " << worldRank << ": after pot = " << potential << "\n";
114     */
115     #endif
116    
117 mmeineke 377 return potential;
118     }
119    
120     double Thermo::getTotalE(){
121    
122     double total;
123    
124     total = this->getKinetic() + this->getPotential();
125     return total;
126     }
127    
128 gezelter 454 double Thermo::getTemperature(){
129    
130     const double kb = 1.9872179E-3; // boltzman's constant in kcal/(mol K)
131     double temperature;
132    
133 gezelter 458 temperature = ( 2.0 * this->getKinetic() ) / ((double)entry_plug->ndf * kb );
134 mmeineke 377 return temperature;
135     }
136    
137 gezelter 483 double Thermo::getPressure() {
138     // returns the pressure in units of atm
139     // Relies on the calculation of the full molecular pressure tensor
140    
141     const double p_convert = 1.63882576e8;
142     double press[9];
143     double pressure;
144    
145     this->getPressureTensor(press);
146    
147     pressure = p_convert * (press[0] + press[4] + press[8]) / 3.0;
148    
149     return pressure;
150     }
151    
152    
153     void Thermo::getPressureTensor(double press[9]){
154     // returns pressure tensor in units amu*fs^-2*Ang^-1
155 gezelter 445 // routine derived via viral theorem description in:
156     // Paci, E. and Marchi, M. J.Phys.Chem. 1996, 100, 4314-4322
157 mmeineke 377
158 gezelter 477 const double e_convert = 4.184e-4;
159 gezelter 483
160     double molmass, volume;
161 gezelter 468 double vcom[3];
162 gezelter 483 double p_local[9], p_global[9];
163 gezelter 468 double theBox[3];
164     double* tau;
165     int i, nMols;
166     Molecule* molecules;
167    
168     nMols = entry_plug->n_mol;
169     molecules = entry_plug->molecules;
170     tau = entry_plug->tau;
171    
172     // use velocities of molecular centers of mass and molecular masses:
173 gezelter 483 for (i=0; i < 9; i++) {
174     p_local[i] = 0.0;
175     p_global[i] = 0.0;
176     }
177 gezelter 475
178 gezelter 468 for (i=0; i < nMols; i++) {
179 gezelter 475 molmass = molecules[i].getCOMvel(vcom);
180 gezelter 483
181     p_local[0] += molmass * (vcom[0] * vcom[0]);
182     p_local[1] += molmass * (vcom[0] * vcom[1]);
183     p_local[2] += molmass * (vcom[0] * vcom[2]);
184     p_local[3] += molmass * (vcom[1] * vcom[0]);
185     p_local[4] += molmass * (vcom[1] * vcom[1]);
186     p_local[5] += molmass * (vcom[1] * vcom[2]);
187     p_local[6] += molmass * (vcom[2] * vcom[0]);
188     p_local[7] += molmass * (vcom[2] * vcom[1]);
189     p_local[8] += molmass * (vcom[2] * vcom[2]);
190 gezelter 468 }
191    
192     // Get total for entire system from MPI.
193 chuckv 479
194 gezelter 468 #ifdef IS_MPI
195 gezelter 483 MPI_Allreduce(p_local,p_global,9,MPI_DOUBLE, MPI_SUM, MPI_COMM_WORLD);
196 gezelter 468 #else
197 gezelter 483 for (i=0; i<9; i++) {
198     p_global[i] = p_local[i];
199     }
200 gezelter 468 #endif // is_mpi
201    
202     entry_plug->getBox(theBox);
203    
204 gezelter 483 volume = theBox[0] * theBox[1] * theBox[2];
205 gezelter 477
206 gezelter 483 for(i=0; i<9; i++) {
207     press[i] = (p_global[i] - tau[i]*e_convert) / volume;
208     }
209 mmeineke 377 }
210    
211     void Thermo::velocitize() {
212    
213     double x,y;
214     double vx, vy, vz;
215     double jx, jy, jz;
216     int i, vr, vd; // velocity randomizer loop counters
217 chuckv 403 double vdrift[3];
218 mmeineke 377 double vbar;
219     const double kb = 8.31451e-7; // kb in amu, angstroms, fs, etc.
220     double av2;
221     double kebar;
222     int n_atoms;
223     Atom** atoms;
224     DirectionalAtom* dAtom;
225     double temperature;
226     int n_oriented;
227     int n_constraints;
228    
229     atoms = entry_plug->atoms;
230     n_atoms = entry_plug->n_atoms;
231     temperature = entry_plug->target_temp;
232     n_oriented = entry_plug->n_oriented;
233     n_constraints = entry_plug->n_constraints;
234    
235 gezelter 458 kebar = kb * temperature * (double)entry_plug->ndf /
236     ( 2.0 * (double)entry_plug->ndfRaw );
237 chuckv 403
238 mmeineke 377 for(vr = 0; vr < n_atoms; vr++){
239    
240     // uses equipartition theory to solve for vbar in angstrom/fs
241    
242     av2 = 2.0 * kebar / atoms[vr]->getMass();
243     vbar = sqrt( av2 );
244 gezelter 444
245 mmeineke 377 // vbar = sqrt( 8.31451e-7 * temperature / atoms[vr]->getMass() );
246    
247     // picks random velocities from a gaussian distribution
248     // centered on vbar
249    
250     vx = vbar * gaussStream->getGaussian();
251     vy = vbar * gaussStream->getGaussian();
252     vz = vbar * gaussStream->getGaussian();
253    
254     atoms[vr]->set_vx( vx );
255     atoms[vr]->set_vy( vy );
256     atoms[vr]->set_vz( vz );
257     }
258 chuckv 401
259     // Get the Center of Mass drift velocity.
260    
261 chuckv 403 getCOMVel(vdrift);
262 mmeineke 377
263     // Corrects for the center of mass drift.
264     // sums all the momentum and divides by total mass.
265    
266     for(vd = 0; vd < n_atoms; vd++){
267    
268     vx = atoms[vd]->get_vx();
269     vy = atoms[vd]->get_vy();
270     vz = atoms[vd]->get_vz();
271 chuckv 401
272 mmeineke 377 vx -= vdrift[0];
273     vy -= vdrift[1];
274     vz -= vdrift[2];
275    
276     atoms[vd]->set_vx(vx);
277     atoms[vd]->set_vy(vy);
278     atoms[vd]->set_vz(vz);
279     }
280     if( n_oriented ){
281    
282     for( i=0; i<n_atoms; i++ ){
283    
284     if( atoms[i]->isDirectional() ){
285    
286     dAtom = (DirectionalAtom *)atoms[i];
287    
288     vbar = sqrt( 2.0 * kebar * dAtom->getIxx() );
289     jx = vbar * gaussStream->getGaussian();
290    
291     vbar = sqrt( 2.0 * kebar * dAtom->getIyy() );
292     jy = vbar * gaussStream->getGaussian();
293 gezelter 454
294 mmeineke 377 vbar = sqrt( 2.0 * kebar * dAtom->getIzz() );
295     jz = vbar * gaussStream->getGaussian();
296    
297     dAtom->setJx( jx );
298     dAtom->setJy( jy );
299     dAtom->setJz( jz );
300     }
301     }
302     }
303     }
304 chuckv 401
305 chuckv 403 void Thermo::getCOMVel(double vdrift[3]){
306 chuckv 401
307     double mtot, mtot_local;
308     double vdrift_local[3];
309     int vd, n_atoms;
310     Atom** atoms;
311    
312     // We are very careless here with the distinction between n_atoms and n_local
313     // We should really fix this before someone pokes an eye out.
314    
315     n_atoms = entry_plug->n_atoms;
316     atoms = entry_plug->atoms;
317    
318     mtot_local = 0.0;
319     vdrift_local[0] = 0.0;
320     vdrift_local[1] = 0.0;
321     vdrift_local[2] = 0.0;
322    
323     for(vd = 0; vd < n_atoms; vd++){
324    
325     vdrift_local[0] += atoms[vd]->get_vx() * atoms[vd]->getMass();
326     vdrift_local[1] += atoms[vd]->get_vy() * atoms[vd]->getMass();
327     vdrift_local[2] += atoms[vd]->get_vz() * atoms[vd]->getMass();
328    
329     mtot_local += atoms[vd]->getMass();
330     }
331    
332     #ifdef IS_MPI
333 mmeineke 447 MPI_Allreduce(&mtot_local,&mtot,1,MPI_DOUBLE,MPI_SUM, MPI_COMM_WORLD);
334     MPI_Allreduce(vdrift_local,vdrift,3,MPI_DOUBLE,MPI_SUM, MPI_COMM_WORLD);
335 chuckv 401 #else
336     mtot = mtot_local;
337     for(vd = 0; vd < 3; vd++) {
338     vdrift[vd] = vdrift_local[vd];
339     }
340     #endif
341    
342     for (vd = 0; vd < 3; vd++) {
343     vdrift[vd] = vdrift[vd] / mtot;
344     }
345    
346     }
347