View Compilation Error

0_0_23814658_13394.cpp: In function 'void operate()':
0_0_23814658_13394.cpp:182:4: error: reference to 'rank' is ambiguous
    rank(b[i][1]);
    ^
0_0_23814658_13394.cpp:169:6: note: candidates are: void rank(int)
 void rank(int rt){
      ^
In file included from GCC4.9.2/x86_64-w64-mingw32/include/c++/bits/move.h:57:0,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/bits/stl_pair.h:59,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/utility:70,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/algorithm:60,
                 from 0_0_23814658_13394.cpp:4:
GCC4.9.2/x86_64-w64-mingw32/include/c++/type_traits:1340:12: note:                 template<class> struct std::rank
     struct rank
            ^