diff --git a/src/multibody/model.hxx b/src/multibody/model.hxx
index eb4efeaf90979f12d4901f41e9235450d539700c..cee1244d40aa2ff1b7125739c832d8783357cff7 100644
--- a/src/multibody/model.hxx
+++ b/src/multibody/model.hxx
@@ -237,58 +237,58 @@ namespace se3
   }
 
 
-  inline Data::Data (const Model & ref)
+  inline Data::Data (const Model & model)
     :joints(0)
-    ,a((std::size_t)ref.njoint)
-    ,a_gf((std::size_t)ref.njoint)
-    ,v((std::size_t)ref.njoint)
-    ,f((std::size_t)ref.njoint)
-    ,oMi((std::size_t)ref.njoint)
-    ,liMi((std::size_t)ref.njoint)
-    ,tau(ref.nv)
-    ,nle(ref.nv)
-    ,oMf((std::size_t)ref.nFrames)
-    ,Ycrb((std::size_t)ref.njoint)
-    ,M(ref.nv,ref.nv)
-    ,ddq(ref.nv)
-    ,Yaba((std::size_t)ref.njoint)
-    ,u(ref.nv)
-    ,Ag(6,ref.nv)
-    ,Fcrb((std::size_t)ref.njoint)
-    ,lastChild((std::size_t)ref.njoint)
-    ,nvSubtree((std::size_t)ref.njoint)
-    ,U(ref.nv,ref.nv)
-    ,D(ref.nv)
-    ,tmp(ref.nv)
-    ,parents_fromRow((std::size_t)ref.nv)
-    ,nvSubtree_fromRow((std::size_t)ref.nv)
-    ,J(6,ref.nv)
-    ,iMf((std::size_t)ref.njoint)
-    ,com((std::size_t)ref.njoint)
-    ,vcom((std::size_t)ref.njoint)
-    ,acom((std::size_t)ref.njoint)
-    ,mass((std::size_t)ref.njoint)
-    ,Jcom(3,ref.nv)
+    ,a((std::size_t)model.njoint)
+    ,a_gf((std::size_t)model.njoint)
+    ,v((std::size_t)model.njoint)
+    ,f((std::size_t)model.njoint)
+    ,oMi((std::size_t)model.njoint)
+    ,liMi((std::size_t)model.njoint)
+    ,tau(model.nv)
+    ,nle(model.nv)
+    ,oMf((std::size_t)model.nFrames)
+    ,Ycrb((std::size_t)model.njoint)
+    ,M(model.nv,model.nv)
+    ,ddq(model.nv)
+    ,Yaba((std::size_t)model.njoint)
+    ,u(model.nv)
+    ,Ag(6,model.nv)
+    ,Fcrb((std::size_t)model.njoint)
+    ,lastChild((std::size_t)model.njoint)
+    ,nvSubtree((std::size_t)model.njoint)
+    ,U(model.nv,model.nv)
+    ,D(model.nv)
+    ,tmp(model.nv)
+    ,parents_fromRow((std::size_t)model.nv)
+    ,nvSubtree_fromRow((std::size_t)model.nv)
+    ,J(6,model.nv)
+    ,iMf((std::size_t)model.njoint)
+    ,com((std::size_t)model.njoint)
+    ,vcom((std::size_t)model.njoint)
+    ,acom((std::size_t)model.njoint)
+    ,mass((std::size_t)model.njoint)
+    ,Jcom(3,model.nv)
     ,JMinvJt()
     ,llt_JMinvJt()
     ,lambda_c()
-    ,sDUiJt(ref.nv,ref.nv)
-    ,torque_residual(ref.nv)
-    ,dq_after(ref.nv)
+    ,sDUiJt(model.nv,model.nv)
+    ,torque_residual(model.nv)
+    ,dq_after(model.nv)
     ,impulse_c()
   {
     /* Create data strcture associated to the joints */
-    for(Model::Index i=0;i<(Model::JointIndex)(ref.njoint);++i) 
-      joints.push_back(CreateJointData::run(ref.joints[i]));
+    for(Model::Index i=0;i<(Model::JointIndex)(model.njoint);++i) 
+      joints.push_back(CreateJointData::run(model.joints[i]));
 
     /* Init for CRBA */
     M.fill(0);
-    for(Model::Index i=0;i<(Model::Index)(ref.njoint);++i ) { Fcrb[i].resize(6,ref.nv); }
-    computeLastChild(ref);
+    for(Model::Index i=0;i<(Model::Index)(model.njoint);++i ) { Fcrb[i].resize(6,model.nv); }
+    computeLastChild(model);
 
     /* Init for Cholesky */
     U.setIdentity();
-    computeParents_fromRow(ref);
+    computeParents_fromRow(model);
 
     /* Init Jacobian */
     J.setZero();
@@ -298,7 +298,7 @@ namespace se3
     
     a[0].setZero();
     v[0].setZero();
-    a_gf[0] = -ref.gravity;
+    a_gf[0] = -model.gravity;
     f[0].setZero();
     oMi[0].setIdentity();
     liMi[0].setIdentity();