--- trunk/OOPSE/libmdtools/NPTi.cpp	2003/07/14 22:38:13	600
+++ trunk/OOPSE/libmdtools/NPTi.cpp	2003/07/15 19:56:08	617
@@ -42,7 +42,7 @@ void NPTi::moveA() {
 
   double rj[3];
   double instaTemp, instaPress, instaVol;
-  double tt2, tb2;
+  double tt2, tb2, scaleFactor;
 
   tt2 = tauThermostat * tauThermostat;
   tb2 = tauBarostat * tauBarostat;
@@ -76,10 +76,8 @@ void NPTi::moveA() {
     for (j = 0; j < 3; j++) 
       pos[j] += dt * (vel[j] + eta*rj[j]);
 
-
     atoms[i]->setPos( pos );
 
-
     if( atoms[i]->isDirectional() ){
 
       dAtom = (DirectionalAtom *)atoms[i];
@@ -127,12 +125,23 @@ void NPTi::moveA() {
     }                
 
   }
+
   // Scale the box after all the positions have been moved:
   
-  cerr << "eta = " << eta 
-       << "; exp(dt*eta) = " << exp(eta*dt) << "\n";
-  
-  info->scaleBox(exp(dt*eta));  
+  scaleFactor = exp(dt*eta);
+
+  if ((scaleFactor > 1.1) || (scaleFactor < 0.9)) {
+    sprintf( painCave.errMsg,
+             "NPTi error: Attempting a Box scaling of more than 10 percent"
+             " check your tauBarostat, as it is probably too small!\n"
+             " eta = %lf, scaleFactor = %lf\n", eta, scaleFactor
+             );
+    painCave.isFatal = 1;
+    simError();
+  } else {         
+    info->scaleBox(exp(dt*eta));      
+  }
+
 }
 
 void NPTi::moveB( void ){