this is related to this question i have asked here : c++ : filling map of maps via map instance allocation from a vector of maps and is unresolved...
The code is all provided there .. the error message (updated here with the first important part of the error that I forgot to report there) is :
Program received signal SIGSEGV, Segmentation fault.
0x0804f9d4 in __gnu_cxx::new_allocator<std::pair<char* const, int> >::construct (this=0xbffff06f, __p=0x8057428, __val=...)
at /usr/include/c++/4.6/ext/new_allocator.h:108
108 { ::new((void *)__p) _Tp(__val); }
(gdb) backtrace
#0 0x0804f9d4 in __gnu_cxx::new_allocator<std::pair<char* const, int> >::construct (this=0xbffff06f, __p=0x8057428, __val=...)
at /usr/include/c++/4.6/ext/new_allocator.h:108
#1 0x0804f38e in std::_Rb_tree<char*, std::pair<char* const, int>, std::_Select1st<std::pair<char* const, int> >, std::less<char*>, std::allocator<std::pair<char* const, int> > >::_M_create_node (this=0x8098d1c, __x=...) at /usr/include/c++/4.6/bits/stl_tree.h:381
#2 0x0804e209 in std::_Rb_tree<char*, std::pair<char* const, int>, std::_Select1st<std::pair<char* const, int> >, std::less<char*>, std::allocator<std::pair<char* const, int> > >::_M_clone_node (this=0x8098d1c, __x=0xfffffffd) at /usr/include/c++/4.6/bits/stl_tree.h:427
#3 0x0804c5e5 in std::_Rb_tree<char*, std::pair<char* const, int>, std::_Select1st<std::pair<char* const, int> >, std::less<char*>, std::allocator<std::pair<char* const, int> > >::_M_copy (this=0x8098d1c, __x=0xfffffffd, __p=0x8098d20) at /usr/include/c++/4.6/bits/stl_tree.h:1036
#4 0x0804bd45 in std::_Rb_tree<char*, std::pair<char* const, int>, std::_Select1st<std::pair<char* const, int> >, std::less<char*>, std::allocator<std::pair<char* const, int> > >::operator= (this=0x8098d1c, __x=...) at /usr/include/c++/4.6/bits/stl_tree.h:945
#5 0x0804a6bc in std::map<char*, int, std::less<char*>, std::allocator<std::pair<char* const, int> > >::operator= (this=0x8098d1c, __x=...)
at /usr/include/c++/4.6/bits/stl_map.h:255
#6 0x080493d3 in MyProg::classify (trainData=..., testsData=...) at my_prog.cpp:78
#7 0x08049c46 in main () at my_prog.cpp:193
I have marked the point of exact error in that linked post. Could someone point out about the origin of this error.
ps. how is it related to allocators? plus I dont want to bother about allocators unless it is absolutely necessary here.
Edit: here is the code (copied from the link above)
Note; <--
marks the point of error
InnerMap inmap;
vector<InnerMap> vec_inmap;
vec_inmap.resize (8);
int vec_inmap_sz = 8;
vec_inmap.insert (vec_inmap.end (), 8, inmap);
vector<InnerMap>::iterator vec_inmap_it = vec_inmap.begin ();
InnerMap::iterator inmap_it;
MiddlMap mdmap, curr_mdmap;
vector<MiddlMap> vec_mdmap;
vec_mdmap.resize (8);
int vec_mdmap_sz = 8;
vec_mdmap.insert (vec_mdmap.end (), 8, mdmap);
vector<MiddlMap>::iterator vec_mdmap_it = vec_mdmap.begin ();
MiddlMap::iterator mdmap_it;
OuterMap otmap;
OuterMap::iterator otmap_it;
i.e. I store (empty) copies of inmap
and mdmap
(Q. is it that these copies are by reference ?) in the respective vectors, and then pick up these later from the vectors through the respective vector iterators, and then fill the maps accordingly. Here is how:
for (i = 0; i != trainSize; i++) {
...
if (curr_key_otmap != int_key) {
otmap[int_key] = *vec_mdmap_it;
vec_mdmap_it++;
mdmap_count++;
if (mdmap_count == vec_mdmap_sz) {
vec_mdmap_sz += 8;
vec_mdmap.resize (vec_mdmap_sz);
vec_mdmap.insert (vec_mdmap.end(), 8, mdmap);
}
curr_key_otmap = int_key;
curr_mdmap = otmap[curr_key_otmap];
}
mdmap_it = curr_mdmap.find (int_val);
if (mdmap_it == curr_mdmap.end ()) {
curr_mdmap[int_val] = *vec_inmap_it; <--
curr_mdmap[int_val][char_str] = 1;
vec_inmap_it++;
inmap_count++;
if (inmap_count == vec_inmap_sz) {
vec_inmap_sz += 8;
vec_inmap.resize (vec_inmap_sz);
vec_inmap.insert (vec_inmap.end(), 8, inmap);
}
} else {
inmap_it = (*mdmap_it).second.find (char_str);
if (inmap_it == (*mdmap_it).second.end ()) {
(*mdmap_it).second[char_str] = 1;
} else {
(*mdmap_it).second[char_str] += 1;
}
}
...
} //for ends