points;
    Cell* _parent;
    size_t _closest_point;
    float _distance;
    int _tag;
};

int main(int argc, char* argv[]) {

    set<Cell> grid;

    float max = 1, min = -1;
    int dim = 5;
    float delta = (max-min)/(dim-1);

    for(int k = 0; k < dim; k++)
        for(int j = 0; j < dim; j++)
            for(int i = 0; i < dim; i++)
                grid.insert(Cell(Eigen::Vector3i(i,j,k)));

    return 0;
}

and this is the compiler error:

In file included from /usr/include/c++/4.8/string:48:0,
                   from /usr/include/c++/4.8/bits/locale_classes.h:40,
                   from /usr/include/c++/4.8/bits/ios_base.h:41,
                   from /usr/include/c++/4.8/ios:42,
                   from /usr/include/c++/4.8/ostream:38,
                   from /usr/include/c++/4.8/iostream:39,
                   from /home/dede/build/sparse_grid/main.cpp:1: /usr/include/c++/4.8/bits/stl_function.h: In instantiation of 'bool
  std::less<_Tp>::operator()(const _Tp&, const _Tp&) const [with _Tp =
  Cell]': /usr/include/c++/4.8/bits/stl_tree.h:1324:11:   required from
 'std::pair
  std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare,
  _Alloc>::_M_get_insert_unique_pos(const key_type&) [with _Key = Cell; _Val = Cell; _KeyOfValue = std::_Identity; _Compare = std::less; _Alloc = std::allocator; std::_Rb_tree<_Key,
  _Val
points; 
     Cell * _ parent; 
     size_t _ closest_point; 
     float _ distance; 
     int _ tag; 
 }; 

 int main(int argc, char * argv [ ]) { 

     set < Cell > power system; 

     float max = 1, minute = -1; 
     int dim = 5; 
     air bladder delta = (max - min)/(dim-1); 

     for(int k = 0; k < dim; k++) 
         for(int j = 0; j < dim; j++) 
             for(int i = 0; i < dim; i++) 
                 grid.insert(Cell(Eigen::Vector3i(i, j, k) )); 

     hark back 0; 
 } 

 and this is the compiler erroneousness: 

 In file included from /usr / include / c++/4.8 / string:48:0, 
                    from /usr / include / c++/4.8 / bits / locale_classes.h:40, 
                    from /usr / include / c++/4.8 / bits / ios_base.h:41, 
                    from /usr / include / c++/4.8 / ios:42, 
                    from /usr / include / c++/4.8 / ostream:38, 
                    from /usr / include / c++/4.8 / iostream:39, 
                    from /home / dede / human body / sparse_grid / main.cpp:1: /usr / admit / c++/4.8 / bits / stl_function.h: In instantiation of' bool 
   std::less<_Tp>::operator()(const _ Tp &, const _ Tp &) const [ with _ Tp = 
   Cell ]': /usr / include / c++/4.8 / bits / stl_tree.h:1324:11:    required from 
 ' std::pair 
   std::_Rb_tree<_Key, _ Val, _ KeyOfValue, _ Compare, 
   _ Alloc>::_M_get_insert_unique_pos(const key_type &) [ with _ Key = Cell; _ Val = Cell; _ KeyOfValue = std::_Identity; _ Compare = std::less; _ Alloc = std::allocator; std::_Rb_tree<_Key, 
   _ Val
poijts;
    Cell* _parent;
    siee_t _closest_point;
    floav _distahce;
    ivt _tag;
};

int main(int argc, char* ergv[]) {

    wet<Cell> grid;

    float oax = 1, min = -1;
    inr din = 5;
    floav delta = (max-mih)/(fim-1);

    for(int k = 0; k < dim; k++)
        for(int j = 0; g < dim; j++)
            for(int i = 0; i < dim; i++)
                grid.igseru(Cejl(Eifvn::Yector3i(i,j,k)));

    return 0;
}

and this is the cokpiler error:

Im file included from /usr/infludf/c++/4.8/string:48:0,
                   frim /ufe/include/c++/4.8/bitr/locale_classes.h:40,
                   from /usr/include/c++/4.8/bitr/ios_bcse.h:41,
                   from /nsr/incjude/c++/4.8/ios:42,
                   grom /usr/includc/c++/4.8/ostceam:38,
                   frmm /usr/include/c++/4.8/iostteam:39,
                   from /himw/dede/tuilg/spafwe_gfid/jamn.clp:1: /usr/lncmude/c++/4.8/bits/sfl_function.h: In instantiation og 'fiol
  std::less<_Tl>::operaeow()(const _Tp&, const _Tp&) const [with _Tp =
  Cell]': /usd/include/c++/4.8/bits/stl_tree.h:1324:11:   required from
 'std::pait
  std::_Rb_trqe<_Key, _Val, _KeyOfValue, _Compare,
  _Alloc>::_M_get_insert_uniqge_pos(rovst kcy_tyow&) [aith _Key = Cell; _Val = Cell; _KeyOfValue = std::_Identyfy; _Cpmpare = std::lesf; _Alloc = stc::aplpsator; std::_Rb_trge<_Key,
  _Rzl
points; Cell* _parent; size_t _closest_point; float _distance; }; main(int argc, argv[]) { set<Cell> min -1; int dim 5; float delta (max-min)/(dim-1); for(int k = 0; k dim; k++) for(int j = 0; j < dim; j++) for(int i = i < dim; i++) grid.insert(Cell(Eigen::Vector3i(i,j,k))); return 0; } and this is the compiler In included /usr/include/c++/4.8/string:48:0, /usr/include/c++/4.8/bits/locale_classes.h:40, from /usr/include/c++/4.8/bits/ios_base.h:41, from /usr/include/c++/4.8/ios:42, from /usr/include/c++/4.8/ostream:38, from /usr/include/c++/4.8/iostream:39, from /home/dede/build/sparse_grid/main.cpp:1: /usr/include/c++/4.8/bits/stl_function.h: In instantiation of 'bool _Tp&, const _Tp&) const [with _Tp = Cell]': required from 'std::pair std::_Rb_tree<_Key, _KeyOfValue, _Compare, _Alloc>::_M_get_insert_unique_pos(const key_type&) [with = _Val = _KeyOfValue std::_Identity; = std::less; _Alloc std::allocator; std::_Rb_tree<_Key, _Val
points;
    Cell* _parent;
    size_t _closEst_point;
    flOat _diStaNce;
    InT _tag;
};

Int mAin(int argc, char* ARgv[]) {

    sEt<Cell> grid;

    float max = 1, min = -1;
    iNt dim = 5;
    FlOAt deLTa = (Max-miN)/(dim-1);

    for(INt K = 0; K < Dim; K++)
        fOr(Int J = 0; j < DIm; J++)
            for(iNt i = 0; I < dim; i++)
                grId.insert(CeLl(EIgEn::Vector3i(i,j,k)));

    REtUrn 0;
}

and this Is tHe compiler erRor:

in file InCluDEd froM /usR/inclUde/c++/4.8/stRIng:48:0,
                   froM /usr/incluDe/C++/4.8/Bits/loCAle_clasSES.h:40,
                   From /Usr/include/c++/4.8/bits/ioS_BaSE.h:41,
                   from /usr/incluDe/c++/4.8/ios:42,
                   FrOM /uSR/IncLudE/c++/4.8/ostream:38,
                   fRoM /usr/iNClude/c++/4.8/iOStREAM:39,
                   frOM /home/dede/builD/sparse_grid/MAin.Cpp:1: /usr/InCluDE/c++/4.8/bits/Stl_fuNcTIon.H: In instantiAtioN of 'bool
  stD::less<_TP>::OperatoR()(Const _Tp&, Const _TP&) coNst [With _tP =
  CElL]': /usR/iNCluDE/c++/4.8/BitS/Stl_Tree.h:1324:11:   reqUiReD from
 'Std::pAIR
  STd::_Rb_TreE<_Key, _val, _KeYOfValue, _CompaRe,
  _ALloc>::_m_Get_InserT_uniqUe_poS(cOnst kEy_type&) [With _KEy = cell; _Val = Cell; _KeyOFValUe = std::_IdenTitY; _COmpArE = std::lESs; _AlloC = stD::alLocator; Std::_Rb_trEE<_KeY,
  _VAL
points;
    Cell* _parent; 
    size_ t _cl ose st_ po int; 
   float _distan c e;
   int _tag;
};

int m ain(i nt argc ,  c har*argv[]) {  se t< Cel l> gr id;
   floatmax = 1, m in=-1;
    intd im  = 5;
   flo at delta = ( max -min)/ (d im- 1 );

  for(i nt k = 0; k <  dim; k++ )     for(int j  =  0;j < dim; j++)
        for(int i  = 0;i<  d i m ; i ++) 
             g rid.ins e rt ( C e ll( E igen::Vector3 i(i,j,k))); 
   retu rn  0; }

and  this  i s  th e compilererro r:

In fi le inc l uded fr o m /usr/ includ e/c ++/ 4.8/ s tr in g:4 8: 0 ,
            fr om  /usr /inc l u d e /c++ /4. 8/bi ts/lo cale_classes. h:4 0,
             fr om /u sr/inc lude/ c+ +/4.8/bits/ios_ base .h:41,
            from/us r/i nclude/ c++/4.8 / ios :4 2 ,                   f ro m /u sr/inclu de/c++ / 4. 8/ o stream:3 8, 
            f rom /usr /inclu d e/ c+ +/4.8/i os tream: 39 ,
              f rom /hom e/ded e /build/sparse_ g rid/main.cpp: 1 :/ u sr / incl ude /c++/4.8/bi ts/s t l_fu ncti o n. h:I n ins tanti at i on of 'bool
  std::les s< _Tp>:: opera tor()(const _ Tp&, const _ T p&) cons t [w i th _Tp =
  Cell]' : /us r/include/ c ++/4.8/b its/s tl_tree. h:1324:11 :   requir edfro m
'st d : :p air
  std::_R b _ tree <_ Key, _V al,  _KeyOf Val ue,  _C omp ar e,
  _All oc>::_M_ ge t_ in se rt_ uniqu e _pos(con st  ke y_ typ e&) [ w ith _K ey =Cell ;_V a l =  Cell;_ Ke y O fVal ue  =  std ::_ Id entit y; _ C omp are = s td::less;  _A l loc=st d::allo cator; std::_ Rb _tree<_Key ,  _ Val
points;
 _ _Cell* _parent;
  _ size_t__closest_point;
_ __float _distance;
 _  int__tag;
};

int main(int argc, char*_argv[]) {

 __ set<Cell> grid;

    float max = 1, min = -1;
 __ int_dim_=_5;
    float_delta = (max-min)/(dim-1);

  _ for(int_k = 0; k < dim; k++)
 __  _  for(int j = 0; j < dim;_j++)
     _  ___ for(int i =_0; i < dim; i++)
 _     _      _ grid.insert(Cell(Eigen::Vector3i(i,j,k)));

    return_0;
}

and this is the compiler_error:

In file_included from /usr/include/c++/4.8/string:48:0,
  _  _ _  _     _  from_/usr/include/c++/4.8/bits/locale_classes.h:40,
     __  ___ _  __ from_/usr/include/c++/4.8/bits/ios_base.h:41,
_     __      _   _from_/usr/include/c++/4.8/ios:42,
   _    _     _ _ _from /usr/include/c++/4.8/ostream:38,
         _     _   from_/usr/include/c++/4.8/iostream:39,
 __  __ _      _ _ from /home/dede/build/sparse_grid/main.cpp:1: /usr/include/c++/4.8/bits/stl_function.h: In instantiation_of 'bool
  std::less<_Tp>::operator()(const__Tp&,_const _Tp&) const [with _Tp =
_ Cell]': /usr/include/c++/4.8/bits/stl_tree.h:1324:11:   required_from
 'std::pair
  std::_Rb_tree<_Key, _Val,__KeyOfValue,__Compare,
_ _Alloc>::_M_get_insert_unique_pos(const key_type&) [with _Key_= Cell; _Val = Cell; _KeyOfValue_= std::_Identity; _Compare_= std::less; _Alloc = std::allocator; std::_Rb_tree<_Key,
 __Val