--- trunk/OOPSE/libmdtools/NPTi.cpp	2003/07/14 22:38:13	600
+++ trunk/OOPSE/libmdtools/NPTi.cpp	2003/07/15 17:10:50	611
@@ -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;
@@ -127,12 +127,22 @@ 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 ){