--- trunk/OOPSE/libmdtools/Integrator.cpp	2004/04/15 16:18:26	1113
+++ trunk/OOPSE/libmdtools/Integrator.cpp	2004/04/19 03:52:27	1118
@@ -687,6 +687,7 @@ template<typename T> void Integrator<T>::rotationPropa
 
   double angle;
   double A[3][3], I[3][3];
+  int i, j, k;
 
   // use the angular velocities to propagate the rotation matrix a
   // full time step
@@ -694,6 +695,21 @@ template<typename T> void Integrator<T>::rotationPropa
   sd->getA(A);
   sd->getI(I);
 
+  if (sd->isLinear()) {
+    i = sd->linearAxis();
+    j = (i+1)%3;
+    k = (i+2)%3;
+    
+    angle = dt2 * ji[j] / I[j][j];
+    this->rotate( k, i, angle, ji, A );
+
+    angle = dt * ji[k] / I[k][k];
+    this->rotate( i, j, angle, ji, A);
+
+    angle = dt2 * ji[j] / I[j][j];
+    this->rotate( k, i, angle, ji, A );
+
+  } else {
   // rotate about the x-axis
   angle = dt2 * ji[0] / I[0][0];
   this->rotate( 1, 2, angle, ji, A );
@@ -714,6 +730,7 @@ template<typename T> void Integrator<T>::rotationPropa
   angle = dt2 * ji[0] / I[0][0];
   this->rotate( 1, 2, angle, ji, A );
 
+  }
   sd->setA( A  );
 }