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root/group/trunk/mdtools/md_code/Thermo.cpp
Revision: 254
Committed: Thu Jan 30 20:03:37 2003 UTC (21 years, 5 months ago) by chuckv
File size: 7334 byte(s)
Log Message:
Bug fixes for mpi version of code

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 cerr << "creating thermo stream\n";
22 gaussStream = new gaussianSPRNG( baseSeed );
23 cerr << "created thermo stream\n";
24 }
25
26 Thermo::~Thermo(){
27 delete gaussStream;
28 }
29
30 double Thermo::getKinetic(){
31
32 const double e_convert = 4.184E-4; // convert kcal/mol -> (amu A^2)/fs^2
33 double vx2, vy2, vz2;
34 double kinetic, v_sqr;
35 int kl;
36 double jx2, jy2, jz2; // the square of the angular momentums
37
38 DirectionalAtom *dAtom;
39
40 int n_atoms;
41 double kinetic_global;
42 Atom** atoms;
43
44
45 n_atoms = entry_plug->n_atoms;
46 atoms = entry_plug->atoms;
47
48 kinetic = 0.0;
49 kinetic_global = 0.0;
50 for( kl=0; kl < n_atoms; kl++ ){
51
52 vx2 = atoms[kl]->get_vx() * atoms[kl]->get_vx();
53 vy2 = atoms[kl]->get_vy() * atoms[kl]->get_vy();
54 vz2 = atoms[kl]->get_vz() * atoms[kl]->get_vz();
55
56 v_sqr = vx2 + vy2 + vz2;
57 kinetic += atoms[kl]->getMass() * v_sqr;
58
59 if( atoms[kl]->isDirectional() ){
60
61 dAtom = (DirectionalAtom *)atoms[kl];
62
63 jx2 = dAtom->getJx() * dAtom->getJx();
64 jy2 = dAtom->getJy() * dAtom->getJy();
65 jz2 = dAtom->getJz() * dAtom->getJz();
66
67 kinetic += (jx2 / dAtom->getIxx()) + (jy2 / dAtom->getIyy())
68 + (jz2 / dAtom->getIzz());
69 }
70 }
71 #ifdef IS_MPI
72 MPI::COMM_WORLD.Allreduce(&kinetic,&kinetic_global,1,MPI_DOUBLE,MPI_SUM);
73 kinetic = kinetic_global;
74 #endif //is_mpi
75
76 kinetic = kinetic * 0.5 / e_convert;
77
78 return kinetic;
79 }
80
81 double Thermo::getPotential(){
82
83 double potential;
84 double potential_global;
85 int el, nSRI;
86 SRI** sris;
87
88 sris = entry_plug->sr_interactions;
89 nSRI = entry_plug->n_SRI;
90
91 potential = 0.0;
92 potential_global = 0.0;
93 potential += entry_plug->lrPot;
94
95 // std::cerr << "long range potential: " << potential << "\n";
96 for( el=0; el<nSRI; el++ ){
97
98 potential += sris[el]->get_potential();
99 }
100
101 // Get total potential for entire system from MPI.
102 #ifdef IS_MPI
103 MPI::COMM_WORLD.Allreduce(&potential,&potential_global,1,MPI_DOUBLE,MPI_SUM);
104 potential = potential_global;
105 #endif // is_mpi
106
107 return potential;
108 }
109
110 double Thermo::getTotalE(){
111
112 double total;
113
114 total = this->getKinetic() + this->getPotential();
115 return total;
116 }
117
118 double Thermo::getTemperature(){
119
120 const double kb = 1.9872179E-3; // boltzman's constant in kcal/(mol K)
121 double temperature;
122
123 int ndf = 3 * entry_plug->n_atoms + 3 * entry_plug->n_oriented
124 - entry_plug->n_constraints - 3;
125
126 temperature = ( 2.0 * this->getKinetic() ) / ( ndf * kb );
127 return temperature;
128 }
129
130 double Thermo::getPressure(){
131
132 // const double conv_Pa_atm = 9.901E-6; // convert Pa -> atm
133 // const double conv_internal_Pa = 1.661E-7; //convert amu/(fs^2 A) -> Pa
134 // const double conv_A_m = 1.0E-10; //convert A -> m
135
136 return 0.0;
137 }
138
139 void Thermo::velocitize() {
140
141 double x,y;
142 double vx, vy, vz;
143 double jx, jy, jz;
144 int i, vr, vd; // velocity randomizer loop counters
145 double vdrift[3];
146 double mtot = 0.0;
147 double vbar;
148 const double kb = 8.31451e-7; // kb in amu, angstroms, fs, etc.
149 double av2;
150 double kebar;
151 int ndf; // number of degrees of freedom
152 int ndfRaw; // the raw number of degrees of freedom
153 int n_atoms;
154 Atom** atoms;
155 DirectionalAtom* dAtom;
156 double temperature;
157 int n_oriented;
158 int n_constraints;
159
160 atoms = entry_plug->atoms;
161 n_atoms = entry_plug->n_atoms;
162 temperature = entry_plug->target_temp;
163 n_oriented = entry_plug->n_oriented;
164 n_constraints = entry_plug->n_constraints;
165
166
167 ndfRaw = 3 * n_atoms + 3 * n_oriented;
168 ndf = ndfRaw - n_constraints - 3;
169 kebar = kb * temperature * (double)ndf / ( 2.0 * (double)ndfRaw );
170
171 for(vr = 0; vr < n_atoms; vr++){
172
173 // uses equipartition theory to solve for vbar in angstrom/fs
174
175 av2 = 2.0 * kebar / atoms[vr]->getMass();
176 vbar = sqrt( av2 );
177
178 // vbar = sqrt( 8.31451e-7 * temperature / atoms[vr]->getMass() );
179
180 // picks random velocities from a gaussian distribution
181 // centered on vbar
182 #ifndef USE_SPRNG
183 /* If we are using mpi, we need to use the SPRNG random
184 generator. The non drand48 generator will just repeat
185 the same numbers for every node creating a non-gaussian
186 distribution for the simulation. drand48 is fine for the
187 single processor version of the code, but SPRNG should
188 still be preferred for consistency.
189 */
190
191 #ifdef IS_MPI
192 #error "SPRNG random number generator must be used for MPI"
193 #else
194 // warning "Using drand48 for random number generation"
195 #endif // is_mpi
196
197 x = drand48();
198 y = drand48();
199 vx = vbar * sqrt( -2.0 * log(x)) * cos(2 * M_PI * y);
200
201 x = drand48();
202 y = drand48();
203 vy = vbar * sqrt( -2.0 * log(x)) * cos(2 * M_PI * y);
204
205 x = drand48();
206 y = drand48();
207 vz = vbar * sqrt( -2.0 * log(x)) * cos(2 * M_PI * y);
208
209 #endif // use_spring
210
211 #ifdef USE_SPRNG
212 vx = vbar * gaussStream->getGaussian();
213 vy = vbar * gaussStream->getGaussian();
214 vz = vbar * gaussStream->getGaussian();
215 #endif // use_spring
216
217 atoms[vr]->set_vx( vx );
218 atoms[vr]->set_vy( vy );
219 atoms[vr]->set_vz( vz );
220 }
221
222 // Corrects for the center of mass drift.
223 // sums all the momentum and divides by total mass.
224
225 mtot = 0.0;
226 vdrift[0] = 0.0;
227 vdrift[1] = 0.0;
228 vdrift[2] = 0.0;
229 for(vd = 0; vd < n_atoms; vd++){
230
231 vdrift[0] += atoms[vd]->get_vx() * atoms[vd]->getMass();
232 vdrift[1] += atoms[vd]->get_vy() * atoms[vd]->getMass();
233 vdrift[2] += atoms[vd]->get_vz() * atoms[vd]->getMass();
234
235 mtot = mtot + atoms[vd]->getMass();
236 }
237
238 for (vd = 0; vd < 3; vd++) {
239 vdrift[vd] = vdrift[vd] / mtot;
240 }
241
242 for(vd = 0; vd < n_atoms; vd++){
243
244 vx = atoms[vd]->get_vx();
245 vy = atoms[vd]->get_vy();
246 vz = atoms[vd]->get_vz();
247
248
249 vx -= vdrift[0];
250 vy -= vdrift[1];
251 vz -= vdrift[2];
252
253 atoms[vd]->set_vx(vx);
254 atoms[vd]->set_vy(vy);
255 atoms[vd]->set_vz(vz);
256 }
257 if( n_oriented ){
258
259 for( i=0; i<n_atoms; i++ ){
260
261 if( atoms[i]->isDirectional() ){
262
263 dAtom = (DirectionalAtom *)atoms[i];
264
265 #ifndef USE_SPRNG
266
267 #ifdef IS_MPI
268 #error "SPRNG random number generator must be used for MPI"
269 #else // is_mpi
270 //warning "Using drand48 for random number generation"
271 #endif // is_MPI
272
273 vbar = sqrt( 2.0 * kebar * dAtom->getIxx() );
274 x = drand48();
275 y = drand48();
276 jx = vbar * sqrt( -2.0 * log(x)) * cos(2 * M_PI * y);
277
278 vbar = sqrt( 2.0 * kebar * dAtom->getIyy() );
279 x = drand48();
280 y = drand48();
281 jy = vbar * sqrt( -2.0 * log(x)) * cos(2 * M_PI * y);
282
283 vbar = sqrt( 2.0 * kebar * dAtom->getIzz() );
284 x = drand48();
285 y = drand48();
286 jz = vbar * sqrt( -2.0 * log(x)) * cos(2 * M_PI * y);
287
288 #else //use_sprng
289
290 vbar = sqrt( 2.0 * kebar * dAtom->getIxx() );
291 jx = vbar * gaussStream->getGaussian();
292
293 vbar = sqrt( 2.0 * kebar * dAtom->getIyy() );
294 jy = vbar * gaussStream->getGaussian();
295
296 vbar = sqrt( 2.0 * kebar * dAtom->getIzz() );
297 jz = vbar * gaussStream->getGaussian();
298 #endif //use_sprng
299
300 dAtom->setJx( jx );
301 dAtom->setJy( jy );
302 dAtom->setJz( jz );
303 }
304 }
305 }
306 }