--- trunk/OOPSE/libmdtools/Thermo.cpp	2003/04/07 16:56:38	468
+++ trunk/OOPSE/libmdtools/Thermo.cpp	2003/07/09 15:33:46	582
@@ -134,44 +134,97 @@ double Thermo::getPressure(){
   return temperature;
 }
 
-double Thermo::getPressure(){
-  // returns pressure in units amu*fs^-2*Ang^-1
+double Thermo::getEnthalpy() {
+
+  const double e_convert = 4.184E-4; // convert kcal/mol -> (amu A^2)/fs^2
+  double u, p, v;
+  double press[9];
+
+  u = this->getTotalE();
+
+  this->getPressureTensor(press);
+  p = (press[0] + press[4] + press[8]) / 3.0;
+
+  v = this->getVolume();
+
+  return (u + (p*v)/e_convert);
+}
+
+double Thermo::getVolume() {
+
+  return entry_plug->boxVol;
+}
+
+double Thermo::getPressure() {
+
+  // Relies on the calculation of the full molecular pressure tensor
+  
+  const double p_convert = 1.63882576e8;
+  double press[9];
+  double pressure;
+
+  this->getPressureTensor(press);
+
+  pressure = p_convert * (press[0] + press[4] + press[8]) / 3.0;
+
+  return pressure;
+}
+
+
+void Thermo::getPressureTensor(double press[9]){
+  // returns pressure tensor in units amu*fs^-2*Ang^-1
   // routine derived via viral theorem description in:
   // Paci, E. and Marchi, M. J.Phys.Chem. 1996, 100, 4314-4322
 
-  const double convert = 4.184e-4;
-  double mtot;
+  const double e_convert = 4.184e-4;
+
+  double molmass, volume;
   double vcom[3];
-  double p_local, p_sum, p_mol, virial;
+  double p_local[9], p_global[9];
   double theBox[3];
-  double* tau;
+  //double* tau;
   int i, nMols;
   Molecule* molecules;
 
   nMols = entry_plug->n_mol;
   molecules = entry_plug->molecules;
-  tau = entry_plug->tau;
+  //tau = entry_plug->tau;
 
   // use velocities of molecular centers of mass and molecular masses:
-  p_local = 0.0;
+  for (i=0; i < 9; i++) {    
+    p_local[i] = 0.0;
+    p_global[i] = 0.0;
+  }
+
   for (i=0; i < nMols; i++) {
-    molecules[i].getCOMvel(mtot, vcom);
-    p_local += mtot* (vcom[0]*vcom[0] + vcom[1]*vcom[1] + vcom[2]*vcom[2]);
+    molmass = molecules[i].getCOMvel(vcom);
+
+    p_local[0] += molmass * (vcom[0] * vcom[0]); 
+    p_local[1] += molmass * (vcom[0] * vcom[1]); 
+    p_local[2] += molmass * (vcom[0] * vcom[2]); 
+    p_local[3] += molmass * (vcom[1] * vcom[0]); 
+    p_local[4] += molmass * (vcom[1] * vcom[1]); 
+    p_local[5] += molmass * (vcom[1] * vcom[2]); 
+    p_local[6] += molmass * (vcom[2] * vcom[0]); 
+    p_local[7] += molmass * (vcom[2] * vcom[1]); 
+    p_local[8] += molmass * (vcom[2] * vcom[2]); 
   }
 
   // Get total for entire system from MPI.
+
 #ifdef IS_MPI
-  MPI_Allreduce(&p_local,&p_sum,1,MPI_DOUBLE, MPI_SUM, MPI_COMM_WORLD);
+  MPI_Allreduce(p_local,p_global,9,MPI_DOUBLE, MPI_SUM, MPI_COMM_WORLD);
 #else
-  p_sum = p_local; 
+  for (i=0; i<9; i++) {
+    p_global[i] = p_local[i]; 
+  }
 #endif // is_mpi
 
-  virial = tau[0] + tau[4] + tau[8];
-  entry_plug->getBox(theBox);
+  volume = entry_plug->boxVol;
 
-  p_mol = (p_sum - virial*convert) / (3.0 * theBox[0] * theBox[1]* theBox[2]);
-  
-  return p_mol;
+  for(i=0; i<9; i++) {
+    press[i] = (p_global[i] - entry_plug->tau[i]*e_convert) / volume;
+  }
 }
 
 void Thermo::velocitize() {