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root/group/trunk/OOPSE/libmdtools/Thermo.cpp
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Comparing trunk/OOPSE/libmdtools/Thermo.cpp (file contents):
Revision 475 by gezelter, Tue Apr 8 12:44:18 2003 UTC vs.
Revision 588 by gezelter, Thu Jul 10 17:10:56 2003 UTC

# Line 134 | Line 134 | double Thermo::getPressure(){
134    return temperature;
135   }
136  
137 < double Thermo::getPressure(){
138 <  // returns pressure in units amu*fs^-2*Ang^-1
137 > double Thermo::getEnthalpy() {
138 >
139 >  const double e_convert = 4.184E-4; // convert kcal/mol -> (amu A^2)/fs^2
140 >  double u, p, v;
141 >  double press[3][3];
142 >
143 >  u = this->getTotalE();
144 >
145 >  this->getPressureTensor(press);
146 >  p = (press[0][0] + press[1][1] + press[2][2]) / 3.0;
147 >
148 >  v = this->getVolume();
149 >
150 >  return (u + (p*v)/e_convert);
151 > }
152 >
153 > double Thermo::getVolume() {
154 >
155 >  return entry_plug->boxVol;
156 > }
157 >
158 > double Thermo::getPressure() {
159 >
160 >  // Relies on the calculation of the full molecular pressure tensor
161 >  
162 >  const double p_convert = 1.63882576e8;
163 >  double press[3][3];
164 >  double pressure;
165 >
166 >  this->getPressureTensor(press);
167 >
168 >  pressure = p_convert * (press[0][0] + press[1][1] + press[2][2]) / 3.0;
169 >
170 >  return pressure;
171 > }
172 >
173 >
174 > void Thermo::getPressureTensor(double press[3][3]){
175 >  // returns pressure tensor in units amu*fs^-2*Ang^-1
176    // routine derived via viral theorem description in:
177    // Paci, E. and Marchi, M. J.Phys.Chem. 1996, 100, 4314-4322
178  
179 <  const double convert = 4.184e-4;
180 <  double molmass;
179 >  const double e_convert = 4.184e-4;
180 >
181 >  double molmass, volume;
182    double vcom[3];
183 <  double p_local, p_sum, p_mol, virial;
184 <  double theBox[3];
147 <  double* tau;
148 <  int i, nMols;
183 >  double p_local[9], p_global[9];
184 >  int i, j, k, nMols;
185    Molecule* molecules;
186  
187    nMols = entry_plug->n_mol;
188    molecules = entry_plug->molecules;
189 <  tau = entry_plug->tau;
189 >  //tau = entry_plug->tau;
190  
191    // use velocities of molecular centers of mass and molecular masses:
192 <  p_local = 0.0;
192 >  for (i=0; i < 9; i++) {    
193 >    p_local[i] = 0.0;
194 >    p_global[i] = 0.0;
195 >  }
196  
197    for (i=0; i < nMols; i++) {
198      molmass = molecules[i].getCOMvel(vcom);
199 <    p_local += (vcom[0]*vcom[0] + vcom[1]*vcom[1] + vcom[2]*vcom[2]) * molmass;
199 >
200 >    p_local[0] += molmass * (vcom[0] * vcom[0]);
201 >    p_local[1] += molmass * (vcom[0] * vcom[1]);
202 >    p_local[2] += molmass * (vcom[0] * vcom[2]);
203 >    p_local[3] += molmass * (vcom[1] * vcom[0]);
204 >    p_local[4] += molmass * (vcom[1] * vcom[1]);
205 >    p_local[5] += molmass * (vcom[1] * vcom[2]);
206 >    p_local[6] += molmass * (vcom[2] * vcom[0]);
207 >    p_local[7] += molmass * (vcom[2] * vcom[1]);
208 >    p_local[8] += molmass * (vcom[2] * vcom[2]);
209    }
210  
211    // Get total for entire system from MPI.
212 +
213   #ifdef IS_MPI
214 <  MPI_Allreduce(&p_local,&p_sum,1,MPI_DOUBLE, MPI_SUM, MPI_COMM_WORLD);
214 >  MPI_Allreduce(p_local,p_global,9,MPI_DOUBLE, MPI_SUM, MPI_COMM_WORLD);
215   #else
216 <  p_sum = p_local;
216 >  for (i=0; i<9; i++) {
217 >    p_global[i] = p_local[i];
218 >  }
219   #endif // is_mpi
220  
221 <  virial = tau[0] + tau[4] + tau[8];
171 <  entry_plug->getBox(theBox);
221 >  volume = entry_plug->boxVol;
222  
223 <  p_mol = (p_sum - virial*convert) / (3.0 * theBox[0] * theBox[1]* theBox[2]);
224 <  
225 <  return p_mol;
223 >  for(i = 0; i < 3; i++) {
224 >    for (j = 0; j < 3; j++) {
225 >      k = 3*i + j;
226 >      press[i][j] = (p_global[k] - entry_plug->tau[k]*e_convert) / volume;
227 >    }
228 >  }
229   }
230  
231   void Thermo::velocitize() {

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