bool testBezierTetrahedronGeometry()
	{
		BezierTetrahedronSetTopologyContainer *container=root->get<BezierTetrahedronSetTopologyContainer>(root->SearchDown);
		typename MechanicalObject::SPtr dofs = root->get<MechanicalObject>(std::string("BezierTetrahedronTopology/"));
		typename MechanicalObject::WriteVecCoord coords = dofs->writePositions();
		size_t i,j;	
		BezierDegreeType degree=container->getDegree();
		sofa::component::topology::VecPointID indexArray;
		sofa::helper::vector<TetrahedronBezierIndex> tbiArray=container->getTetrahedronBezierIndexArray();
		for ( i = 0; i<container->getNumberOfTetrahedra(); i++)
		{
			indexArray.clear();
			container->getGlobalIndexArrayOfBezierPointsInTetrahedron(i, indexArray);

			for (j=0;j<tbiArray.size();++j) {

				if (j>=4) {
					// test if the position is correct
					Coord pos=coords[indexArray[0]]*(Real)tbiArray[j][0]/degree+coords[indexArray[1]]*(Real)tbiArray[j][1]/degree+coords[indexArray[2]]*(Real)tbiArray[j][2]/degree+coords[indexArray[3]]*(Real)tbiArray[j][3]/degree;
					if ((pos-coords[indexArray[j]]).norm()>1e-5) {
						ADD_FAILURE() << "Wrong control point position in tetrahedron no  : "<<i <<" for point of local index " <<j
						<< " Got point position="<<coords[indexArray[j]]<<" instead of "<<pos<<std::endl;
						return false;
					}
				}

			}
		}
		return true;
	}
    /** Constrain one particle, and not the last one.
    Detects bugs like not setting the projection matrix entries beyond the last constrained particle
    */
    void init_2bones()
    {
        joints.clear();
        
        typename MechanicalObject::WriteVecCoord x = dofs->writePositions();
        x.resize(2);
        VecCoord rigids(2);
        DataTypes::setCPos(x[1], CPos(0,1,0));
        DataTypes::setCRot(x[1], CRot(0.707107,0, 0, 0.707107)); // rotation x: 90 degree
        Coord target(CPos(1,1,1), CRot(0,0.382683,0,0.92388)); //rotation y : 45 degrees

        
        joints.resize(2);

        joints[0].addChannel(x[0], 0);
        joints[0].addChannel(target, 1);
        joints[0].setRestPosition(x[0]);

        joints[1].addChannel(x[1], 0);
        joints[1].setRestPosition(x[1]);
        joints[1].mParentIndex = 0;

        helper::vector<int> bones(2,0); bones[1] = 1;
        projection->setSkeletalMotion(joints, bones);

        /// Init
        sofa::simulation::getSimulation()->init(root.get());
        simulation->animate(root.get(),0.25);
        simulation->animate(root.get(),0.25);

    }
	bool testBezierTetrahedronMass()
	{
		BezierTetrahedronSetTopologyContainer *container=root->get<BezierTetrahedronSetTopologyContainer>(root->SearchDown);
		BezierTetrahedronSetGeometryAlgorithms *geo=root->get<BezierTetrahedronSetGeometryAlgorithms>(root->SearchDown);
	
		typename MechanicalObject::SPtr dofs = root->get<MechanicalObject>(std::string("BezierTetrahedronTopology/"));
		typename MechanicalObject::WriteVecCoord coords = dofs->writePositions();
		MeshMatrixMass *mass=root->get<MeshMatrixMass>(root->SearchDown);
		const sofa::helper::vector<typename MeshMatrixMass::MassVector> & mv=mass->tetrahedronMassInfo.getValue();
		const sofa::helper::vector<typename MeshMatrixMass::MassType> &ma =mass->vertexMassInfo.getValue();

		size_t i,j,k,rank;	
		BezierDegreeType degree=container->getDegree();
		Real tetraVol1,tetraVol2,totalVol1,totalVol2;
		
		sofa::helper::vector<TetrahedronBezierIndex> tbiArray=container->getTetrahedronBezierIndexArray();
		size_t nbControlPoints=(degree+1)*(degree+2)*(degree+3)/6;
		totalVol1=0;
		for ( i = 0; i<container->getNumberOfTetrahedra(); i++)
		{
			
//				const BezierTetrahedronSetTopologyContainer::VecPointID &indexArray=container->getGlobalIndexArrayOfBezierPoints(i);
			
			
			/// get the volume of the tetrahedron
			tetraVol1=geo->computeTetrahedronVolume(i);
			tetraVol2=0;
			// compute the total volume
			totalVol1+=tetraVol1;
			/// check that the sum of the volume matrix elements is equal to the volume of the tetrahedron
			for (rank=0,j=0;j<nbControlPoints;j++) {
				for (k=j;k<nbControlPoints;k++,rank++) {
					if (k==j) 
						// add diagonal term
						tetraVol2+=mv[i][rank]; 
					else 
						// add 2 times off-diagonal term
						tetraVol2+=2*mv[i][rank]; 
				}
			}
			if (fabs(tetraVol1-tetraVol2)>1e-5) {
				ADD_FAILURE() << "Wrong mass matrix in tetrahedron no  : "<<i
				<< " Got total mass="<<tetraVol2<<" instead of "<<tetraVol1<<std::endl;
				return false;
			}
		}
		// compute totalVol2 as the total of the lumped volume
		totalVol2=0;
		for ( i = 0; i<ma.size(); i++)
		{
			totalVol2+=ma[i];
		}
		if (fabs(totalVol1-totalVol2)>1e-5) {
			ADD_FAILURE() << "Wrong total vertex mass value."
			 << " Got total vertex mass="<<totalVol2<<" instead of "<<totalVol1<<std::endl;
			return false;
		}
		return true;
	}
    bool test_projectPosition()
    {
       VecCoord xprev(numNodes);
       typename MechanicalObject::WriteVecCoord x = dofs->writePositions();
       for (unsigned i=0; i<numNodes; i++){
           xprev[i] = x[i] = CPos(i,0,0);
       }
//       cerr<<"test_projectPosition, x before = " << x << endl;
       projection->projectPosition(core::MechanicalParams::defaultInstance(), *dofs->write(core::VecCoordId::position()) );
//       cerr<<"test_projectPosition, x after = " << x << endl;

       bool succeed=true;
       typename Indices::const_iterator it = indices.begin(); // must be sorted
       for(unsigned i=0; i<numNodes; i++ )
       {
           if ((it!=indices.end()) && ( i==*it ))  // constrained particle
           {
              CPos crossprod = (x[i]-origin).cross(direction); // should be parallel
              Real scal = crossprod*crossprod; // null if x is on the line
//              cerr<<"scal = "<< scal << endl;
              if( !Sofa_test<typename _DataTypes::Real>::isSmall(scal,100) ){
                  succeed = false;
                  ADD_FAILURE() << "Position of constrained particle " << i << " is wrong: " << x[i] ;
              }
               it++;
           }
           else           // unconstrained particle: check that it has not changed
           {
              CPos dx = x[i]-xprev[i];
              Real scal = dx*dx;
//              cerr<<"scal gap = "<< scal << endl;
              if( !Sofa_test<typename _DataTypes::Real>::isSmall(scal,100) ){
                  succeed = false;
                  ADD_FAILURE() << "Position of unconstrained particle " << i << " is wrong: " << x[i] ;
              }
           }

       }
       return succeed;
    }
        /// After simulation compare the positions of points to the theoretical positions.
        bool compareSimulatedToTheoreticalPositions(double convergenceAccuracy, double diffMaxBetweenSimulatedAndTheoreticalPosition)
        {
            // Init simulation
            sofa::simulation::getSimulation()->init(root.get());

            // Compute the theoretical final positions    
            VecCoord finalPos;
            typename AffineMovementConstraint::SPtr affineConstraint  = root->get<AffineMovementConstraint>(root->SearchDown);
            typename MechanicalObject::SPtr dofs = root->get<MechanicalObject>(root->SearchDown);
            typename MechanicalObject::WriteVecCoord x = dofs->writePositions();
            affineConstraint->getFinalPositions( finalPos,*dofs->write(core::VecCoordId::position()) );
            
            // Set random rotation and translation for affine constraint
            randomGenerator.initSeed(seed);
            this->SetRandomTestedRotationAndTranslation(seed);
            // Set data values of affine movement constraint
            affineConstraint->m_rotation.setValue(testedRotation);
            affineConstraint->m_translation.setValue(testedTranslation);

            // Initialize
            size_t numNodes = finalPos.size();
            VecCoord xprev(numNodes);
            VecDeriv dx(numNodes); 
            bool hasConverged = true;
            
            for (size_t i=0; i<numNodes; i++)
            {
                xprev[i] = CPos(0,0,0);
            }

            // Animate
            do
            {
                hasConverged = true;
                sofa::simulation::getSimulation()->animate(root.get(),0.5);
                typename MechanicalObject::ReadVecCoord x = dofs->readPositions();

                // Compute dx
                for (size_t i=0; i<x.size(); i++)
                {
                    dx[i] = x[i]-xprev[i];
                    // Test convergence
                    if(dx[i].norm()>convergenceAccuracy) hasConverged = false;
                }
               
                // xprev = x
                for (size_t i=0; i<numNodes; i++)
                {
                    xprev[i]=x[i];
                }
            }
            while(!hasConverged); // not converged

            // Compare the theoretical positions and the simulated positions   
            bool succeed=true;
            for(size_t i=0; i<finalPos.size(); i++ )
            {
                if((finalPos[i]-x[i]).norm()>diffMaxBetweenSimulatedAndTheoreticalPosition)
                {   
                    succeed = false;
                    ADD_FAILURE() << "final Position of point " << i << " is wrong: " << x[i] << std::endl <<"the expected Position is " << finalPos[i] << std::endl 
                        << "difference = " <<(finalPos[i]-x[i]).norm() << std::endl;
                }
            }
            return succeed;
        }