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  • Graph and permutation problem

    - by user319771
    I have a graph (with nodes and edges) containing symmetry and a group of permutations to label the nodes so no edges are changed (automorphisms). Now I would like to determine for which nodes a permutation exchanges two equivalent (i.e. nodes with the same color or symmetry class) neighboring nodes. When the nodes with equivalent neighbors stay the same, simply checking if the neighbors are exchanged in the permutation is enough. However, when the nodes with equivalent neighbors are also permuted (i.e. there are multiple nodes with the same color/symmetry class with the same equivalent neighbors), the problem becomes more complex. Is there any known algorithm for such a problem? Some remarks: The graph has no coordinates, it's a topology only

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  • Timeline graph - how to handle "time gaps"?

    - by ebae
    I've been working with Google chart API and annotated timeline. Drawing graphs is fine. I have no problem. However, I need to draw a timeline graph for share prices. And as you may know, share prices are meaningful only between certain times (e.g. from 10AM to 4PM, when the market opens and closes). How do I change the Google timeline graph so that on X-Axis, the range is from 10AM-4PM? Right now, it just draws a long constant line between 4PM till 10AM next day before prices start to move again. Man, I hope that makes sens. (Google finance chart seems to do it). Thank you SO much for whoever can answer. You are a CHAMPION!

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  • Boost graph libraries: setting edge weight values

    - by AndyUK
    I am investigating the use of the boost graph libraries in order to apply them to various network problems I have in mind. In the examples I have been looking at the graph edge values ("weights") are always initialized as integers, such as in these Bellman-Ford and Kruskal algorithms eg: int weights[] = { 1, 1, 2, 7, 3, 1, 1, 1 }; My problem is if I try and change the weights to double, I get a heap of warning messages about conversions etc, which so far I have not been able to figure out how to overcome. Does anyone see a way around this?

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  • Graph visualization code in javascript?

    - by Chris Farmer
    Hi. I have a data structure that represents a directed graph, and I want to render that dynamically on an HTML page. Does anyone know of any javascript code that can do a reasonable job with graph layout? These graphs will usually be just a few nodes, maybe ten at the very upper end, so my guess is that performance isn't going to be a big deal. Ideally, I'd like to be able to hook it in with jQuery so that users can tweak the layout manually by dragging the nodes around. Edit: Google's Visualization API seems to be more "graphs as charts" oriented than "graphs as nodes" oriented. I didn't see any node-oriented visualizations already built there, anyway. Do you know that one exists?

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  • Getting specific data from via facebook graph api

    - by Sima
    Hi, is there any possibility how to fetch any specific type of posts from facebook news feed via graph api?For example on my news feed I have statutuses, links, photos, vidoes, and so on..I only want to get the ones with type=status over graph api..I have seen some get parameters in documentation, but nothing like ?type=link..So I have tried /me/home?type=link, but unsurprisingly it have not worked:D So does anyone know how to do that?I can filter it in my PHP app, but then I need to get some further data..When I got 20 posts and only 10 would be statuses, I need to add the 10 remaiming? It is too possible, but I dont know how to do that:D Please help..!Thanks

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  • Facebook Graph - does the user "like" my page?

    - by Ican Zilb
    I am trying to upgrade my iPhone app to use the new facebook graph api. One thing I cannot find is how to find out if the current user connected from my app to facebook is a fan of my facebook page - (i.e. in the new paradigm - whether the user likes my page) In the Rest Api there was a function isFan, but not in the Graph. I can get all items the user likes and search whether one of them is my page, but certainly there must be an easier way instead of going trough thousands of records each time I must check whether he is a fan, right? If someone already figured it out how to do that from their new docs, I'll really appreciate if you share it with me.

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  • Facebook Open Graph Not Showing Object Title

    - by gregavola
    I'm having conflicting reports for our users that people that share Object Graph objects to their wall, are sometimes showing the Object title and other times not. Specifically, every test I do on my own account shows the Object Title, but on their Mobile apps - it doesn't appear. I've tested the Open Graph debugger.So I have a couple of questions: Is there a length limit on the number of characters? Does Facebook not show the whole Object.title on Mobile? Does Facebook scrap the OG tags and if it can't find them or if it timeout do they not receive them? Here is my sample OG url: https://untappd.com/user/gregavola/checkin/35486976 Response from FB: Post on my Wall: What can I do here? What am I missing?

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  • VB.net Network Graph code/algorithm

    - by Jens
    For a school project we need to visualise a computer network graph. The number of computers with specific properties are read from an XML file, and then a graph should be created. Ad random computers are added and removed. Is there any open source project or algorithm that could help us visualising this in VB.net? Or would you suggest us to switch to java. Update: We eventually switched java and used the Jung libraries because this was easier for us to understand and implement.

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  • CSS Graph- Bars not showing correctly

    - by Olivia
    I'm trying to create a CSS/HTML based graph using this tutorial here. However instead of putting the data directly into the html code I'm importing it from a CSV file using PHP with the following code. <?PHP /* Open CSV file */ $handle = fopen("defects.csv", "r"); $c = 0; /* gets data from csv file */ while (($data = fgetcsv($handle, 1000, ",")) !== FALSE) { /* stores dates as variable $date */ $date[$c] = $data[0]; $c++; /* inserts defect data into html code */ echo "<dd class=\"p" . $data[2] . "\"><span><b>" . $data[2] . "</b></span></dd>"; echo "<dd class=\"sub p" . $data[3] . "\" ><span><b>" . $data[3] . "</b></span></dd>"; } echo "</dl>"; echo "<ul class=\"xAxis\">"; /* X AXIS */ /* inserts date data into html code for x axis */ for ($d=0; $d < $c; $d++) { echo "<li>" . $date[$d] . "</li>"; } ?> The values are being placed correctly on the chart, but the bars aren't appearing. The CSS code I have for the bars is: /* default column styling */ dl#csschart span{ height:50%; background:url(../images/barx.png) repeat-y; } dl#csschart .sub{ margin-left:-33px; } dl#csschart .sub span{ background:url(../images/subBarx.png) repeat-y; } Just in case it helps, I've print screened how the graph should look. You can see it at: http://allured.info/graph/failgraph.png

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  • representing graph using database

    - by prosseek
    I need to represent graph information with database. Let's say, a is connected to b, c, and d. a -- b |_ c |_ d I can have a node table for a, b, c, and d, and I can also have a link table (FROM, TO) - (a,b), (a,c), (a,d). For other implementation there might be a way to store the link info as (a,b,c,d), but the number of elements in the table is variable. Q1 : Is there a way to represent variable elements in a table? Q2 : Is there any general way to represent the graph structure using database?

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  • Find a node in a Graph that minimizes the distance between two other nodes

    - by Andrés
    Here is the thing. I have a directed weighted graph G, with V vertices and E edges. Given two nodes in the graph, let's say A, and B, and given the weight of an edge A-B denoted as w(A, B), I need to find a node C so that max(w(A, C), w(B, C)) is minimal among all possibilities. By possibilities I mean all the values C can take. I don't know if it is completely clear, if it's not, I'll try to be more precise. Thanks in advance.

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  • Structure of Astar (A*) graph search data in C#

    - by Shawn Mclean
    How do you structure you graphs/nodes in a graph search class? I'm basically creating a NavMesh and need to generate the nodes from 1 polygon to the other. The edge that joins both polygons will be the node. I'll then run A* on these Nodes to calculate the shortest path. I just need to know how to structure my classes and their properties? I know for sure I wont need to create a fully blown undirected graph with nodes and edges.

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  • custom C++ boost::lambda expression help

    - by aaa
    hello. A little bit of background: I have some strange multiple nested loops which I converted to flat work queue (basically collapse single index loops to single multi-index loop). right now each loop is hand coded. I am trying to generalized approach to work with any bounds using lambda expressions: For example: // RANGE(i,I,N) is basically a macro to generate `int i = I; i < N; ++i ` // for (RANGE(lb, N)) { // for (RANGE(jb, N)) { // for (RANGE(kb, max(lb, jb), N)) { // for (RANGE(ib, jb, kb+1)) { // is equivalent to something like (overload , to produce range) flat<1, 3, 2, 4>((_2, _3+1), (max(_4,_3), N), N, N) the internals of flat are something like: template<size_t I1, size_t I2, ..., class L1_, class L2, ..._> boost::array<int,4> flat(L1_ L1, L2_ L2, ...){ //boost::array<int,4> current; class variable bool advance; L2_ l2 = L2.bind(current); // bind current value to lambda { L1_ l1 = L1.bind(current); //bind current value to innermost lambda l1.next(); advance = !(l1 < l1.upper()); // some internal logic if (advance) { l2.next(); current[0] = l1.lower(); } } //..., } my question is, can you give me some ideas how to write lambda (derived from boost) which can be bound to index array reference to return upper, lower bounds according to lambda expression? thank you much

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  • GCC emits extra code for boost::shared_ptr dereference

    - by Checkers
    I have the following code: #include <boost/shared_ptr.hpp> struct Foo { int a; }; static int A; void func_shared(const boost::shared_ptr<Foo> &foo) { A = foo->a; } void func_raw(Foo * const foo) { A = foo->a; } I thought the compiler would create identical code, but for shared_ptr version an extra seemingly redundant instruction is emitted. Disassembly of section .text: 00000000 <func_raw(Foo*)>: 0: 55 push ebp 1: 89 e5 mov ebp,esp 3: 8b 45 08 mov eax,DWORD PTR [ebp+8] 6: 5d pop ebp 7: 8b 00 mov eax,DWORD PTR [eax] 9: a3 00 00 00 00 mov ds:0x0,eax e: c3 ret f: 90 nop 00000010 <func_shared(boost::shared_ptr<Foo> const&)>: 10: 55 push ebp 11: 89 e5 mov ebp,esp 13: 8b 45 08 mov eax,DWORD PTR [ebp+8] 16: 5d pop ebp 17: 8b 00 mov eax,DWORD PTR [eax] 19: 8b 00 mov eax,DWORD PTR [eax] 1b: a3 00 00 00 00 mov ds:0x0,eax 20: c3 ret I'm just curious, is this necessary, or it is just an optimizer's shortcoming? Compiling with g++ 4.1.2, -O3 -NDEBUG.

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  • standard way to perform a clean shutdown with Boost.Asio

    - by Timothy003
    I'm writing a cross-platform server program in C++ using Boost.Asio. Following the HTTP Server example on this page, I'd like to handle a user termination request without using implementation-specific APIs. I've initially attempted to use the standard C signal library, but have been unable to find a design pattern suitable for Asio. The Windows example's design seems to resemble the signal library closest, but there's a race condition where the console ctrl handler could be called after the server object has been destroyed. I'm trying to avoid race conditions that cause undefined behavior as specified by the C++ standard. Is there a standard (correct) way to stop the server? So far: #include <csignal> #include <functional> #include <boost/asio.hpp> using std::signal; using boost::asio::io_service; extern "C" { static void handle_signal(int); } namespace { std::function<void ()> sighandler; } void handle_signal(int) { sighandler(); } int main() { io_service s; sighandler = std::bind(&io_service::stop, &s); auto res = signal(SIGINT, &handle_signal); // race condition? SIGINT raised before I could set ignore back if (res == SIG_IGN) signal(SIGINT, SIG_IGN); res = signal(SIGTERM, &handle_signal); // race condition? SIGTERM raised before I could set ignore back if (res == SIG_IGN) signal(SIGTERM, SIG_IGN); s.run(); // reset signals signal(SIGTERM, SIG_DFL); signal(SIGINT, SIG_DFL); // is it defined whether handle_signal can still be in execution at this // point? sighandler = nullptr; }

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  • Boost binding a function taking a reference

    - by Jamie Cook
    Hi all, I am having problems compiling the following snippet int temp; vector<int> origins; vector<string> originTokens = OTUtils::tokenize(buffer, ","); // buffer is a char[] array // original loop BOOST_FOREACH(string s, originTokens) { from_string(temp, s); origins.push_back(temp); } // I'd like to use this to replace the above loop std::transform(originTokens.begin(), originTokens.end(), origins.begin(), boost::bind<int>(&FromString<int>, boost::ref(temp), _1)); where the function in question is // the third parameter should be one of std::hex, std::dec or std::oct template <class T> bool FromString(T& t, const std::string& s, std::ios_base& (*f)(std::ios_base&) = std::dec) { std::istringstream iss(s); return !(iss >> f >> t).fail(); } the error I get is 1>Compiling with Intel(R) C++ 11.0.074 [IA-32]... (Intel C++ Environment) 1>C:\projects\svn\bdk\Source\deps\boost_1_42_0\boost/bind/bind.hpp(303): internal error: assertion failed: copy_default_arg_expr: rout NULL, no error (shared/edgcpfe/il.c, line 13919) 1> 1> return unwrapper<F>::unwrap(f, 0)(a[base_type::a1_], a[base_type::a2_]); 1> ^ 1> 1>icl: error #10298: problem during post processing of parallel object compilation Google is being unusually unhelpful so I hope that some one here can provide some insights.

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  • C++ - passing references to boost::shared_ptr

    - by abigagli
    If I have a function that needs to work with a shared_ptr, wouldn't it be more efficient to pass it a reference to it (so to avoid copying the shared_ptr object)? What are the possible bad side effects? I envision two possible cases: 1) inside the function a copy is made of the argument, like in ClassA::take_copy_of_sp(boost::shared_ptr<foo> &sp) { ... m_sp_member=sp; //This will copy the object, incrementing refcount ... } 2) inside the function the argument is only used, like in Class::only_work_with_sp(boost::shared_ptr<foo> &sp) //Again, no copy here { ... sp->do_something(); ... } I can't see in both cases a good reason to pass the boost::shared_ptr by value instead of by reference. Passing by value would only "temporarily" increment the reference count due to the copying, and then decrement it when exiting the function scope. Am I overlooking something? Andrea. EDIT: Just to clarify, after reading several answers : I perfectly agree on the premature-optimization concerns, and I alwasy try to first-profile-then-work-on-the-hotspots. My question was more from a purely technical code-point-of-view, if you know what I mean.

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  • Boost ASIO async_write "Vector iterator not dereferencable"

    - by xeross
    Hey, I've been working on an async boost server program, and so far I've got it to connect. However I'm now getting a "Vector iterator not dereferencable" error. I suspect the vector gets destroyed or dereferenced before he packet gets sent thus causing the error. void start() { Packet packet; packet.setOpcode(SMSG_PING); send(packet); } void send(Packet packet) { cout << "DEBUG> Transferring packet with opcode " << packet.GetOpcode() << endl; async_write(m_socket, buffer(packet.write()), boost::bind(&Session::writeHandler, shared_from_this(), placeholders::error, placeholders::bytes_transferred)); } void writeHandler(const boost::system::error_code& errorCode, size_t bytesTransferred) { cout << "DEBUG> Transfered " << bytesTransferred << " bytes to " << m_socket.remote_endpoint().address().to_string() << endl; } Start gets called once a connection is made. packet.write() returns a uint8_t vector Would it matter if I'd change void send(Packet packet) to void send(Packet& packet) Not in relation to this problem but performance wise.

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  • Boost Date_Time problem compiling a simple program

    - by Andry
    Hello! I'm writing a very stupid program using Boost Date_Time library. int main(int srgc, char** argv) { using namespace boost::posix_time; date d(2002,Feb,1); //an arbitrary date ptime t1(d, hours(5)+nanosec(100)); //date + time of day offset ptime t2 = t1 - minutes(4)+seconds(2); ptime now = second_clock::local_time(); //use the clock date today = now.date(); //Get the date part out of the time } Well I cannot compile it, compiler does not recognize a type... Well I used many features of Boost libs like serialization and more... I correctly built them and, looking in my /usr/local/lib folder I can see that libboost_date_time.so is there (a good sign which means I was able to build that library) When I compile I write the following: g++ -lboost_date_time main.cpp But the errors it showed me when I specify the lib are the same of those ones where I do not specify any lib. What is this? Anyone knows? The error is main.cpp: In function ‘int main(int, char**)’: main.cpp:9: error: ‘date’ was not declared in this scope main.cpp:9: error: expected ‘;’ before ‘d’ main.cpp:10: error: ‘d’ was not declared in this scope main.cpp:10: error: ‘nanosec’ was not declared in this scope main.cpp:13: error: expected ‘;’ before ‘today’

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  • How do you use boost iterators

    - by Neil G
    It worked, and then I added the typedefs so that I could have a const_sparse_iterator as well. Now, when I compile this and try to use sparse_iterator, it says: /Users/neilrg/nn/src/./core/sparse_vector.h:331: error: invalid use of incomplete type 'struct sparse_vector<A>::sparse_iterator' Here's the code. More code here. tempalte<typename T> class sparse_vector { // There is more code at my previous question, but this might be enough...? private: template<typename base_type> class sparse_iterator_private : public boost::iterator_adaptor< sparse_iterator_private<base_type> // Derived , base_type // Base , value_type // Value , boost::random_access_traversal_tag // CategoryOrTraversal > { private: struct enabler {}; // a private type avoids misuse public: sparse_iterator_private() : sparse_iterator_private<base_type>::iterator_adaptor_(0) {} explicit sparse_iterator_private(typename array_type::iterator&& p) : sparse_iterator_private<base_type>::iterator_adaptor_(p) {} private: friend class boost::iterator_core_access; reference dereference() const { return this->base()->value; } }; public: typedef sparse_iterator_private<typename array_type::iterator> sparse_iterator; typedef sparse_iterator_private<typename array_type::const_iterator> const_sparse_iterator; };

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  • Boost shared_ptr use_count function

    - by photo_tom
    My application problem is the following - I have a large structure foo. Because these are large and for memory management reasons, we do not wish to delete them when processing on the data is complete. We are storing them in std::vector<boost::shared_ptr<foo>>. My question is related to knowing when all processing is complete. First decision is that we do not want any of the other application code to mark a complete flag in the structure because there are multiple execution paths in the program and we cannot predict which one is the last. So in our implementation, once processing is complete, we delete all copies of boost::shared_ptr<foo>> except for the one in the vector. This will drop the reference counter in the shared_ptr to 1. Is it practical to use shared_ptr.use_count() to see if it is equal to 1 to know when all other parts of my app are done with the data. One additional reason I'm asking the question is that the boost documentation on the shared pointer shared_ptr recommends not using "use_count" for production code.

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  • Need help with BOOST_FOREACH/compiler bug

    - by Jacek Lawrynowicz
    I know that boost or compiler should be last to blame, but I can't see another explanation here. I'm using msvc 2008 SP1 and boost 1.43. In the following code snippet execution never leaves third BOOST_FOREACH loop typedef Graph<unsigned, unsigned>::VertexIterator Iter; Graph<unsigned, unsigned> g; g.createVertex(0x66); // works fine Iter it = g.getVertices().first, end = g.getVertices().second; for(; it != end; ++it) ; // fine std::pair<Iter, Iter> p = g.getVertices(); BOOST_FOREACH(unsigned handle, p) ; // fine unsigned vertex_count = 0; BOOST_FOREACH(unsigned handle, g.getVertices()) vertex_count++; // oops, infinite loop vertex_count = 0; BOOST_FOREACH(unsigned handle, g.getVertices()) vertex_count++; vertex_count = 0; BOOST_FOREACH(unsigned handle, g.getVertices()) vertex_count++; // ... last block repeated 7 times Iterator code: class Iterator : public boost::iterator_facade<Iterator, unsigned const, boost::bidirectional_traversal_tag> { public: Iterator() : list(NULL), handle(INVALID_ELEMENT_HANDLE) {} explicit Iterator(const VectorElementsList &list, unsigned handle = INVALID_ELEMENT_HANDLE) : list(&list), handle(handle) {} friend std::ostream& operator<<(std::ostream &s, const Iterator &it) { s << "[list: " << it.list <<", handle: " << it.handle << "]"; return s; } private: friend class boost::iterator_core_access; void increment() { handle = list->getNext(handle); } void decrement() { handle = list->getPrev(handle); } unsigned const& dereference() const { return handle; } bool equal(Iterator const& other) const { return handle == other.handle && list == other.list; } const VectorElementsList<T> *list; unsigned handle; }; Some ASM fun: vertex_count = 0; BOOST_FOREACH(unsigned handle, g.getVertices()) // initialization 013E1369 mov edi,dword ptr [___defaultmatherr+8 (13E5034h)] // end iterator handle: 0xFFFFFFFF 013E136F mov ebp,dword ptr [esp+0ACh] // begin iterator handle: 0x0 013E1376 lea esi,[esp+0A8h] // begin iterator list pointer 013E137D mov ebx,esi 013E137F nop // forever loop begin 013E1380 cmp ebp,edi 013E1382 jne main+238h (13E1388h) 013E1384 cmp ebx,esi 013E1386 je main+244h (13E1394h) 013E1388 lea eax,[esp+18h] 013E138C push eax // here iterator is incremented in ram 013E138D call boost::iterator_facade<detail::VectorElementsList<Graph<unsigned int,unsigned int>::VertexWrapper>::Iterator,unsigned int const ,boost::bidirectional_traversal_tag,unsigned int const &,int>::operator++ (13E18E0h) 013E1392 jmp main+230h (13E1380h) vertex_count++; // forever loop end It's easy to see that iterator handle is cached in EBP and it never gets incremented despite of a call to iterator operator++() function. I've replaced Itarator implmentation with one deriving from std::iterator and the issue persisted, so this is not iterator_facade fault. This problem exists only on msvc 2008 SP1 x86 and amd64 release builds. Debug builds on msvc 2008 and debug/release builds on msvc 2010 and gcc 4.4 (linux) works fine. Furthermore the BOOST_FOREACH block must be repeaded exacly 10 times. If it's repeaded 9 times, it's all OK. I guess that due to BOOST_FOREACH use of template trickery (const auto_any), compiler assumes that iterator handle is constant and never reads its real value again. I would be very happy to hear that my code is wrong, correct it and move on with BOOST_FOREACH, which I'm very found of (as opposed to BOOST_FOREVER :). May be related to: http://stackoverflow.com/questions/1275852/why-does-boost-foreach-not-work-sometimes-with-c-strings

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  • How to iterate over modifed std::map values?

    - by Frank
    I have an std::map, and I would like to define an iterator that returns modified values. Typically, a std::map<int,double>::iterator iterates over std::pair<int,double>, and I would like the same behavior, just the double value is multiplied by a constant. I tried it with boost::transform_iterator, but it doesn't compile: #include <map> #include <boost/iterator/transform_iterator.hpp> #include <boost/functional.hpp> typedef std::map<int,double> Map; Map m; m[100] = 2.24; typedef boost::binder2nd< std::multiplies<double> > Function; typedef boost::transform_iterator<Function, Map::value_type*> MultiplyIter; MultiplyIter begin = boost::make_transform_iterator(m.begin(), Function(std::multiplies<double>(), 4)); // now want to similarly create an end iterator // and then iterate over the modified map The error is: error: conversion from 'boost ::transform_iterator< boost::binder2nd<multiplies<double> >, gen_map<int, double>::iterator , boost::use_default, boost::use_default >' to non-scalar type 'boost::transform_iterator< boost::binder2nd<multiplies<double> >, pair<const int, double> * , boost::use_default, boost::use_default >' requested What is gen_map and do I really need it? I adapted the transform_iterator tutorial code from here to write this code ...

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