--- trunk/OOPSE/libmdtools/Thermo.cpp	2003/04/10 16:22:00	486
+++ trunk/OOPSE/libmdtools/Thermo.cpp	2003/07/08 20:56:10	574
@@ -151,14 +151,23 @@ double Thermo::getVolume() {
 }
 
 double Thermo::getVolume() {
-  double theBox[3];
 
-  entry_plug->getBox(theBox);
-  return (theBox[0] * theBox[1] * theBox[2]);
+  double volume;
+  double Hmat[9];
+
+  entry_plug->getBoxM(Hmat);
+
+  // volume = h1 (dot) h2 (cross) h3
+
+  volume = Hmat[0] * ( (Hmat[4]*Hmat[8]) - (Hmat[7]*Hmat[5]) )
+         + Hmat[1] * ( (Hmat[5]*Hmat[6]) - (Hmat[8]*Hmat[3]) )
+         + Hmat[2] * ( (Hmat[3]*Hmat[7]) - (Hmat[6]*Hmat[4]) );
+
+  return volume;
 }
 
 double Thermo::getPressure() {
-  // returns the pressure in units of atm
+
   // Relies on the calculation of the full molecular pressure tensor
   
   const double p_convert = 1.63882576e8;
@@ -222,10 +231,8 @@ void Thermo::getPressureTensor(double press[9]){
   }
 #endif // is_mpi
 
-  entry_plug->getBox(theBox);
+  volume = entry_plug->boxVol;
 
-  volume = theBox[0] * theBox[1] * theBox[2];
-
   for(i=0; i<9; i++) {
     press[i] = (p_global[i] - entry_plug->tau[i]*e_convert) / volume;
   }