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root/group/trunk/OOPSE_old/src/mdtools/libmdCode/Thermo.cpp
Revision: 270
Committed: Fri Feb 14 17:08:46 2003 UTC (21 years, 6 months ago) by mmeineke
File size: 7196 byte(s)
Log Message:
added libmdCode and a couple help scripts

File Contents

# Content
1 #include <cmath>
2 #include <iostream>
3 using namespace std;
4
5 #ifdef IS_MPI
6 #include <mpi.h>
7 #include <mpi++.h>
8 #endif //is_mpi
9
10 #include "Thermo.hpp"
11 #include "SRI.hpp"
12 #include "LRI.hpp"
13 #include "Integrator.hpp"
14
15 #define BASE_SEED 123456789
16
17 Thermo::Thermo( SimInfo* the_entry_plug ) {
18 entry_plug = the_entry_plug;
19 int baseSeed = BASE_SEED;
20
21 gaussStream = new gaussianSPRNG( baseSeed );
22 }
23
24 Thermo::~Thermo(){
25 delete gaussStream;
26 }
27
28 double Thermo::getKinetic(){
29
30 const double e_convert = 4.184E-4; // convert kcal/mol -> (amu A^2)/fs^2
31 double vx2, vy2, vz2;
32 double kinetic, v_sqr;
33 int kl;
34 double jx2, jy2, jz2; // the square of the angular momentums
35
36 DirectionalAtom *dAtom;
37
38 int n_atoms;
39 double kinetic_global;
40 Atom** atoms;
41
42
43 n_atoms = entry_plug->n_atoms;
44 atoms = entry_plug->atoms;
45
46 kinetic = 0.0;
47 kinetic_global = 0.0;
48 for( kl=0; kl < n_atoms; kl++ ){
49
50 vx2 = atoms[kl]->get_vx() * atoms[kl]->get_vx();
51 vy2 = atoms[kl]->get_vy() * atoms[kl]->get_vy();
52 vz2 = atoms[kl]->get_vz() * atoms[kl]->get_vz();
53
54 v_sqr = vx2 + vy2 + vz2;
55 kinetic += atoms[kl]->getMass() * v_sqr;
56
57 if( atoms[kl]->isDirectional() ){
58
59 dAtom = (DirectionalAtom *)atoms[kl];
60
61 jx2 = dAtom->getJx() * dAtom->getJx();
62 jy2 = dAtom->getJy() * dAtom->getJy();
63 jz2 = dAtom->getJz() * dAtom->getJz();
64
65 kinetic += (jx2 / dAtom->getIxx()) + (jy2 / dAtom->getIyy())
66 + (jz2 / dAtom->getIzz());
67 }
68 }
69 #ifdef IS_MPI
70 MPI::COMM_WORLD.Allreduce(&kinetic,&kinetic_global,1,MPI_DOUBLE,MPI_SUM);
71 kinetic = kinetic_global;
72 #endif //is_mpi
73
74 kinetic = kinetic * 0.5 / e_convert;
75
76 return kinetic;
77 }
78
79 double Thermo::getPotential(){
80
81 double potential;
82 double potential_global;
83 int el, nSRI;
84 SRI** sris;
85
86 sris = entry_plug->sr_interactions;
87 nSRI = entry_plug->n_SRI;
88
89 potential = 0.0;
90 potential_global = 0.0;
91 potential += entry_plug->lrPot;
92
93 for( el=0; el<nSRI; el++ ){
94
95 potential += sris[el]->get_potential();
96 }
97
98 // Get total potential for entire system from MPI.
99 #ifdef IS_MPI
100 MPI::COMM_WORLD.Allreduce(&potential,&potential_global,1,MPI_DOUBLE,MPI_SUM);
101 potential = potential_global;
102
103 #endif // is_mpi
104
105 return potential;
106 }
107
108 double Thermo::getTotalE(){
109
110 double total;
111
112 total = this->getKinetic() + this->getPotential();
113 return total;
114 }
115
116 double Thermo::getTemperature(){
117
118 const double kb = 1.9872179E-3; // boltzman's constant in kcal/(mol K)
119 double temperature;
120
121 int ndf = 3 * entry_plug->n_atoms + 3 * entry_plug->n_oriented
122 - entry_plug->n_constraints - 3;
123
124 temperature = ( 2.0 * this->getKinetic() ) / ( ndf * kb );
125 return temperature;
126 }
127
128 double Thermo::getPressure(){
129
130 // const double conv_Pa_atm = 9.901E-6; // convert Pa -> atm
131 // const double conv_internal_Pa = 1.661E-7; //convert amu/(fs^2 A) -> Pa
132 // const double conv_A_m = 1.0E-10; //convert A -> m
133
134 return 0.0;
135 }
136
137 void Thermo::velocitize() {
138
139 double x,y;
140 double vx, vy, vz;
141 double jx, jy, jz;
142 int i, vr, vd; // velocity randomizer loop counters
143 double vdrift[3];
144 double mtot = 0.0;
145 double vbar;
146 const double kb = 8.31451e-7; // kb in amu, angstroms, fs, etc.
147 double av2;
148 double kebar;
149 int ndf; // number of degrees of freedom
150 int ndfRaw; // the raw number of degrees of freedom
151 int n_atoms;
152 Atom** atoms;
153 DirectionalAtom* dAtom;
154 double temperature;
155 int n_oriented;
156 int n_constraints;
157
158 atoms = entry_plug->atoms;
159 n_atoms = entry_plug->n_atoms;
160 temperature = entry_plug->target_temp;
161 n_oriented = entry_plug->n_oriented;
162 n_constraints = entry_plug->n_constraints;
163
164
165 ndfRaw = 3 * n_atoms + 3 * n_oriented;
166 ndf = ndfRaw - n_constraints - 3;
167 kebar = kb * temperature * (double)ndf / ( 2.0 * (double)ndfRaw );
168
169 for(vr = 0; vr < n_atoms; vr++){
170
171 // uses equipartition theory to solve for vbar in angstrom/fs
172
173 av2 = 2.0 * kebar / atoms[vr]->getMass();
174 vbar = sqrt( av2 );
175
176 // vbar = sqrt( 8.31451e-7 * temperature / atoms[vr]->getMass() );
177
178 // picks random velocities from a gaussian distribution
179 // centered on vbar
180 #ifndef USE_SPRNG
181 /* If we are using mpi, we need to use the SPRNG random
182 generator. The non drand48 generator will just repeat
183 the same numbers for every node creating a non-gaussian
184 distribution for the simulation. drand48 is fine for the
185 single processor version of the code, but SPRNG should
186 still be preferred for consistency.
187 */
188
189 #ifdef IS_MPI
190 #error "SPRNG random number generator must be used for MPI"
191 #else
192 // warning "Using drand48 for random number generation"
193 #endif // is_mpi
194
195 x = drand48();
196 y = drand48();
197 vx = vbar * sqrt( -2.0 * log(x)) * cos(2 * M_PI * y);
198
199 x = drand48();
200 y = drand48();
201 vy = vbar * sqrt( -2.0 * log(x)) * cos(2 * M_PI * y);
202
203 x = drand48();
204 y = drand48();
205 vz = vbar * sqrt( -2.0 * log(x)) * cos(2 * M_PI * y);
206
207 #endif // use_spring
208
209 #ifdef USE_SPRNG
210 vx = vbar * gaussStream->getGaussian();
211 vy = vbar * gaussStream->getGaussian();
212 vz = vbar * gaussStream->getGaussian();
213 #endif // use_spring
214
215 atoms[vr]->set_vx( vx );
216 atoms[vr]->set_vy( vy );
217 atoms[vr]->set_vz( vz );
218 }
219
220 // Corrects for the center of mass drift.
221 // sums all the momentum and divides by total mass.
222
223 mtot = 0.0;
224 vdrift[0] = 0.0;
225 vdrift[1] = 0.0;
226 vdrift[2] = 0.0;
227 for(vd = 0; vd < n_atoms; vd++){
228
229 vdrift[0] += atoms[vd]->get_vx() * atoms[vd]->getMass();
230 vdrift[1] += atoms[vd]->get_vy() * atoms[vd]->getMass();
231 vdrift[2] += atoms[vd]->get_vz() * atoms[vd]->getMass();
232
233 mtot = mtot + atoms[vd]->getMass();
234 }
235
236 for (vd = 0; vd < 3; vd++) {
237 vdrift[vd] = vdrift[vd] / mtot;
238 }
239
240 for(vd = 0; vd < n_atoms; vd++){
241
242 vx = atoms[vd]->get_vx();
243 vy = atoms[vd]->get_vy();
244 vz = atoms[vd]->get_vz();
245
246
247 vx -= vdrift[0];
248 vy -= vdrift[1];
249 vz -= vdrift[2];
250
251 atoms[vd]->set_vx(vx);
252 atoms[vd]->set_vy(vy);
253 atoms[vd]->set_vz(vz);
254 }
255 if( n_oriented ){
256
257 for( i=0; i<n_atoms; i++ ){
258
259 if( atoms[i]->isDirectional() ){
260
261 dAtom = (DirectionalAtom *)atoms[i];
262
263 #ifndef USE_SPRNG
264
265 #ifdef IS_MPI
266 #error "SPRNG random number generator must be used for MPI"
267 #else // is_mpi
268 //warning "Using drand48 for random number generation"
269 #endif // is_MPI
270
271 vbar = sqrt( 2.0 * kebar * dAtom->getIxx() );
272 x = drand48();
273 y = drand48();
274 jx = vbar * sqrt( -2.0 * log(x)) * cos(2 * M_PI * y);
275
276 vbar = sqrt( 2.0 * kebar * dAtom->getIyy() );
277 x = drand48();
278 y = drand48();
279 jy = vbar * sqrt( -2.0 * log(x)) * cos(2 * M_PI * y);
280
281 vbar = sqrt( 2.0 * kebar * dAtom->getIzz() );
282 x = drand48();
283 y = drand48();
284 jz = vbar * sqrt( -2.0 * log(x)) * cos(2 * M_PI * y);
285
286 #else //use_sprng
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
294 vbar = sqrt( 2.0 * kebar * dAtom->getIzz() );
295 jz = vbar * gaussStream->getGaussian();
296 #endif //use_sprng
297
298 dAtom->setJx( jx );
299 dAtom->setJy( jy );
300 dAtom->setJz( jz );
301 }
302 }
303 }
304 }