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[BGL] Vertex removal without iterator invalidation?
by Erik Arner 01 Aug '02

01 Aug '02

Yet another question from the BGL newbie... I understand that performing remove_vertex() on graphs with vertexList=vecS will result in invalidated itarors and descriptors for the graph. However, some toy examples i made suggest that if I remove a vertex in such a graph, the vertex descriptors and vertex iterators for vertices with *lower* ID than the removed vertex remain valid after removal, while those for higher ID vertices are invalidated. Is this a true feature of a graph with Vertexlist=vecS, or is my observation a mere coincidence? Is it safe to write code that exploits this "feature"? If it indeed is a feature, I can construct a sorted list of vertices to remove, and remove the vertices in descending order in an easy fashion. If it is not a feature, any suggestions on how to perform this task i.e. removing a list of vertices while keeping the VertexList type vecS? Thanks, Erik

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collection container
by Bohdan 01 Aug '02

01 Aug '02

Has boost any plans on creating container, that holds data by pointer, not by value? Rationale: It is impossible to use normally vector<...> for types that do not have copy constructor. Interface of vector< shared_ptr<...> > doesn't seems to be very convenient( for example with std::algorithms ). And most of all it is not good idea to show vector< shared_ptr<...> > interface to user of my lib, that wants to have container::iterator with normal behavior. AFAIK majority of existing libraries have/need such container ? As to me it is strange that neither stl nor boost have such class. I'm missing 'something' and there are important reasons for not doing this ?

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Creating groups of regular expressions
by cyndi_r2002 01 Aug '02

01 Aug '02

Hi, I have started using Regex++ and like it a lot but is there a way to use grouping constructs using Regex++ / any alternative that would provide the same functionality? Thanks, Cyndi

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Newbie link problem
by Lev Assinovsky 01 Aug '02

01 Aug '02

Hi all! I would like to do a very simple thing: link my main tst.cpp with the third party library $(MYDIR)/libfoo.a. The final command line should be: g++ -o tst tst.cpp -L$(MYDIR) -lfoo Currently I have in my Jamfile: exe tst : tst.cpp : <include>$(ADC_ROOT) <include>$(BOOST_ROOT) <include>"$(HOME)/inc" ; What must be added to provide linking with libfoo.a? (adding of variable LINKLIBS=$(MYDIR)/libfoo.a DOESN'T WORK) Thanks in advance! ---- Lev Assinovsky Aelita Software Corporation O&S Core Division, Programmer ICQ# 165072909 [Non-text portions of this message have been removed]

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boost working with CGAL ??
by Matthias Kronenberger 31 Jul '02

31 Jul '02

I want to use CGAL from http://www.cgal.org together with the boost library. I'm using MSVC 6.5 There seem to be some problems related to namespace issues. I'm getting the following kind of errors: d:\matthias\programmieren\cgal\include\cgal\number_utils.h(236): error C2955: 'is_integral': Fuer die Verwendung einer Vorlagenklasse ist eine Vorlagen-Argumentliste erforderlich d:\matthias\programmieren\boost\boost\type_traits\arithmetic_traits.hpp(38): Siehe Deklaration von 'is_integral'

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Cannot put .o File with Graph Code into .a File
by Adalbert Perbandt 30 Jul '02

30 Jul '02

Hi there, while trying to setup the BGL for use in my environment I'm facing a strange behavior when I try to put a C++ object file which contains instanciations of BGL templates into an object library. My environment: - Sun SPARC machine with Solaris 2.7 (SunOS 5.7) - gcc 2.95.2 The problem shows up when I try to put an .o file into a library file. I can reproduce the error with the file adjacency_list.cpp from the BGL's examples directory: $ pwd /home/perbandt/boost_1_28_0/libs/graph/example $ g++ --version 2.95.2 $ g++ -g -I../../../../boost_1_28_0 -c adjacency_list.cpp $ ls -l adjacency_list.o -rw-r--r-- 1 perbandt relman 3367052 Jul 19 18:40 adjacency_list.o $ which ar /usr/ccs/bin/ar $ ar rv libtest.a adjacency_list.o a - adjacency_list.o Bus error When I try a .a file with already one or more .o files in it I get a segmentation fault. With another file that contains instantiations of BGL templates the problem does appear only when it was compiled with the -g option given. Is this a known problem? Seems to me as if ar would have trouble handling the very long symbol names in the .o file. Or is something wrong with my environment? Thanks, Adalbert Perbandt.

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RE: [Boost-Users] absolute beginner, trying to compile
by James Zappia 30 Jul '02

30 Jul '02

It should be /usr/include/boost Then you can do: #include <boost/whatever.h> /usr/include is the base directory. So how you have it now it would be: #include <boost_1_28_0/boost/whatever.h> And you definitely don't want to do that. Regards, James -----Original Message----- From: thomas strack [mailto:yg-boost-users@gmane.org] Sent: Tuesday, July 30, 2002 10:17 AM To: boost-users(a)yahoogroups.com Subject: [Boost-Users] absolute beginner, trying to compile hi there, unfortunately im not very experienced in c/c++. but i want to try out some functions from the boost libs. so i downloaded and extracted the files (1_28_0) to /usr/include/boost_1_28_0. i think i should be able to use most of the functions now(i hope i didnt misunderstand the doc). i want to use dir_it lib, but i cant compile the testfile coming along with boost. it includes <boost/directory.h> and g++ cant find this file. i dont know exactly how to use the -I and -l options. it would be great if someone could help me out. thx,tommi Info: <http://www.boost.org> Wiki: <http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl> Unsubscribe: <mailto:boost-users-unsubscribe@yahoogroups.com> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

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absolute beginner, trying to compile
by thomas strack 30 Jul '02

30 Jul '02

hi there, unfortunately im not very experienced in c/c++. but i want to try out some functions from the boost libs. so i downloaded and extracted the files (1_28_0) to /usr/include/boost_1_28_0. i think i should be able to use most of the functions now(i hope i didnt misunderstand the doc). i want to use dir_it lib, but i cant compile the testfile coming along with boost. it includes <boost/directory.h> and g++ cant find this file. i dont know exactly how to use the -I and -l options. it would be great if someone could help me out. thx,tommi

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Boost.Lambda - Invoking functors stored in a vector
by Thomas Wenisch 30 Jul '02

30 Jul '02

Hi all, I am storing a set of functors to be invoked in a vector, like this: std::vector< boost::function<void> > functors; At a later time, I would like to invoke each of the functors in the vector. I am trying to do this using Boost.Lambda, to start learning about the Lambda library, but I can't figure out what to write. if I write: std::for_each(functors.begin(), functors.end(), _1); None of the functions are invoked. if I try: for_each(funtors.begin(), functors.end(), _1()); I get compile errors. I suspect this is because the lamda expression is being executed immediately instead of getting passed in to for_each. Everything works fine when I use a separate Invoker function in the usual fashion, like this: void Invoker( boost::function<void> functor) { functor(); } std::for_each(funtors.begin(), functors.end(), Invoker); How can I get the lambda library to invoke each function in the vector? More generally, if the functions were function<void, T>, how could I bind the T parameter in the lambda expression? Thanks for any help, Tom Wenisch Computer Architecture Lab Carnegie Mellon University

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Johnsons BGL implementation for undirected graphs correct?
by Jan de Ruiter 29 Jul '02

29 Jul '02

When I use the BGL johnsons_all_pairs_shortest_paths example (source below)on an undirected graph, some results are quite wrong. For example, the output shows that the distance between node 1 and 6 equals 36. The SP however (1-4-5-8-9-6) = 4+4+4+12+2 = 26. Is there something wrong with me or is the BGL implementation incorrect? Any ideas? Jan de Ruiter //Output 0 1 2 3 4 5 6 7 8 9 0 0 99 111 123 103 107 135 105 111 123 1 -99 0 12 24 4 8 36 6 12 24 2 -111 -12 0 12 -8 -4 24 -6 0 12 3 -123 -24 -12 0 -20 -16 12 -18 -12 0 4 -103 -4 8 20 0 4 32 2 8 20 5 -107 -8 4 16 -4 0 28 -2 4 16 6 -135 -36 -24 -12 -32 -28 0 -30 -24 -12 7 -105 -6 6 18 -2 2 30 0 6 18 8 -111 -12 0 12 -8 -4 24 -6 0 12 9 -123 -24 -12 0 -20 -16 12 -18 -12 0 ------------------------------------------------------------------------- //Source #include <boost/config.hpp> #include <fstream> #include <iostream> #include <vector> #include <iomanip> #include <boost/property_map.hpp> #include <boost/graph/adjacency_list.hpp> #include <boost/graph/graphviz.hpp> #include <boost/graph/johnson_all_pairs_shortest.hpp> int main() { using namespace boost; typedef adjacency_list<vecS, vecS, undirectedS, no_property, property< edge_weight_t, int, property< edge_weight2_t, int > > > Graph; const int V = 10; typedef std::pair < int, int >Edge; Edge edge_array[] = { Edge(0,1), Edge(1,2), Edge(2,3), Edge(1,4), Edge(2,5), Edge(3,6), Edge(4,5), Edge(5,6), Edge(4,7), Edge(5,8), Edge(6,9), Edge(7,8), Edge(8,9) }; const std::size_t E = sizeof(edge_array) / sizeof(Edge); Graph g(edge_array, edge_array + E, V); property_map < Graph, edge_weight_t >::type w = get(edge_weight, g); int weights[] = { 99, 12, 12, 4, 99, 12, 4, 99, 2, 4, 2, 99, 12 }; int *wp = weights; graph_traits < Graph >::edge_iterator e, e_end; for (boost::tie(e, e_end) = edges(g); e != e_end; ++e) w[*e] = *wp++; std::vector < int >d(V, std::numeric_limits < int >::max()); int D[V][V]; johnson_all_pairs_shortest_paths(g, D, distance_map(&d[0])); std::cout << std::setw(5) <<" "; for (int k = 0; k < 10; ++k) std::cout << std::setw(5) << k ; std::cout << std::endl; for (int i = 0; i < 10; ++i) { std::cout <<std::setw(5) << i ; for (int j = 0; j < 10; ++j) { std::cout << std::setw(5) << D[i][j] ; } std::cout << std::endl; } return 0; }

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