docs: public static Vector3D_F64 constraint(TrifocalTensor tensor,
  										  Point2D_F64 p1, Vector3D_F64 l2, Point2D_F64 p3,
  										  Vector3D_F64 ret)
  	{
  		if( ret == null )
  			ret = new Vector3D_F64();
  
  		DMatrixRMaj sum = new DMatrixRMaj(3,3);
  
  		CommonOps_DDRM.add(p1.x,tensor.T1,sum,sum);
  		CommonOps_DDRM.add(p1.y,tensor.T2,sum,sum);
  		CommonOps_DDRM.add(tensor.T3,sum,sum);
  
  		Vector3D_F64 tempV = new Vector3D_F64();
  		GeometryMath_F64.multTran(sum, l2, tempV);
  
  		GeometryMath_F64.cross(tempV, new Vector3D_F64(p3.x, p3.y, 1), ret);
  
  		return ret;
  	}