[Spatial] Fix bug related to 16.04 & 17.10

src/spatial/inertia.hpp

@@ -407,10 +407,11 @@ namespace se3
 
       //// Block 2,2
       skewSquare(-v.linear(),mc,Iout_.template block<3,3>(ANGULAR,ANGULAR));
-      typename Symmetric3::AlphaSkewSquare mcxcx(I.mass(),I.lever());
+//      typename Symmetric3::AlphaSkewSquare mcxcx(I.mass(),I.lever());
 //      const Symmetric3 I_mcxcx(I.inertia() - mcxcx);
-      Symmetric3 I_mcxcx(I.inertia()); I_mcxcx -= mcxcx;
-      Iout_.template block<3,3>(ANGULAR,ANGULAR) += I_mcxcx.vxs(v.angular());
+      Symmetric3 mcxcx(typename Symmetric3::AlphaSkewSquare(I.mass(),I.lever()));
+      Iout_.template block<3,3>(ANGULAR,ANGULAR) += I.inertia().vxs(v.angular());
+      Iout_.template block<3,3>(ANGULAR,ANGULAR) -= mcxcx.vxs(v.angular());
       
     }