ViewVC Help
View File | Revision Log | Show Annotations | View Changeset | Root Listing
root/group/trunk/OOPSE/libmdtools/Thermo.cpp
(Generate patch)

Comparing trunk/OOPSE/libmdtools/Thermo.cpp (file contents):
Revision 458 by gezelter, Fri Apr 4 19:47:19 2003 UTC vs.
Revision 475 by gezelter, Tue Apr 8 12:44:18 2003 UTC

# Line 139 | Line 139 | double Thermo::getPressure(){
139    // routine derived via viral theorem description in:
140    // Paci, E. and Marchi, M. J.Phys.Chem. 1996, 100, 4314-4322
141  
142 <  return 0.0;
142 >  const double convert = 4.184e-4;
143 >  double molmass;
144 >  double vcom[3];
145 >  double p_local, p_sum, p_mol, virial;
146 >  double theBox[3];
147 >  double* tau;
148 >  int i, nMols;
149 >  Molecule* molecules;
150 >
151 >  nMols = entry_plug->n_mol;
152 >  molecules = entry_plug->molecules;
153 >  tau = entry_plug->tau;
154 >
155 >  // use velocities of molecular centers of mass and molecular masses:
156 >  p_local = 0.0;
157 >
158 >  for (i=0; i < nMols; i++) {
159 >    molmass = molecules[i].getCOMvel(vcom);
160 >    p_local += (vcom[0]*vcom[0] + vcom[1]*vcom[1] + vcom[2]*vcom[2]) * molmass;
161 >  }
162 >
163 >  // Get total for entire system from MPI.
164 > #ifdef IS_MPI
165 >  MPI_Allreduce(&p_local,&p_sum,1,MPI_DOUBLE, MPI_SUM, MPI_COMM_WORLD);
166 > #else
167 >  p_sum = p_local;
168 > #endif // is_mpi
169 >
170 >  virial = tau[0] + tau[4] + tau[8];
171 >  entry_plug->getBox(theBox);
172 >
173 >  p_mol = (p_sum - virial*convert) / (3.0 * theBox[0] * theBox[1]* theBox[2]);
174 >  
175 >  return p_mol;
176   }
177  
178   void Thermo::velocitize() {

Diff Legend

Removed lines
+ Added lines
< Changed lines
> Changed lines