- Boost-users - lists.preview.boost.org

[BGL] Bipartite matching
by Swidan, Firas, Ph.D. 14 Sep '06

14 Sep '06

Hi, I was wondering if BGL contains algorithms for (weighted and unweighted) bipartite matching; the documentation site ( http://www.boost.org/libs/graph/doc/table_of_contents.html) shows no trace of such algorithms, neither does googling the users mailing list. Thanks for the help, Firas.

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[Boost.Signal]
by Wu Yinghui, Freddie 14 Sep '06

14 Sep '06

Hi all, I'm a happy user of Boost.Signal, as it brings great power to our software design in terms of loosening all the coupling between components. However, I recently come across a case where a single-shot slot is desired (i.e., a signal-slot connection that is automatically disconnected once the signal is invoked for once). In our current implementation, we have to keep boost::signals::connection object around with the slot implementation, so that it can disconnect it after the first invocation. However, we have this problem of boost::signals::connection management, since one signal may be connected to different signals and we have problem identifying the correct connection to be disconnected. So my question is: Is there any easier way (i.e., ways that doesn't involve the implementation of the slot function itself) that I can add a single-shot signal-slot connection? Any suggestion is appreciated. Cheers, Freddie -- Wu Yinghui, Freddie Research & Development Senior Software Engineer Volume Interactions Pte Ltd 1 Kim Seng Promenade, #12-01 Great World City East Tower Singapore 237994 Tel: +65 62226962 (Ext 216) Fax: +65 62226215 Email: yhwu(a)volumeinteractions.com URL: http://www.volumeinteractions.com Important: This message is intended for the recipient(s) addressed above. It contains privileged and confidential information. If you are not the intended recipient, please notify the sender immediately by replying to this message and then delete it from your system. You must not read, copy, use, or disseminate this communication in any form. Thank you.

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GraphViz sample help?
by Ramy Sadek 14 Sep '06

14 Sep '06

Hi All, I'm trying to create a simple C++ program that loads graphviz files (with arbitrary properties) into a mutable BGL graph by using a dynamic property map. This seemingly simple task has become a much larger task than I expected. So much so that I believe I'm barking up the wrong tree. I have been studying basic_graph<> in the python examples, trying to model my code after it, but several details elude me. So, I'm writing to ask if anyone has an example code that does this and would be kind enough to share it. It would be most helpful to me to see the concrete class definitions alongside the generic ones, to understand how to use them in my code. Thanks in advance! -Ramy

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mingw, bjam and Boost.Python tutorial problem (Import Error)
by Sune Mai 14 Sep '06

14 Sep '06

Hi, I have a problem exactly similar to what is described in great detail in an earlier post to this list (with the same title): http://lists.boost.org/boost-users/2006/02/17367.php Unfortunatly, the thread ends without a solution... Just as in the above post, the dll "hello.pyd" built with bjam (following the Boost.Python tutorial) doesn't export inithello. A manual build does, and the resulting "hello.pyd" works fine when imported into python. One observation that might help pinpoint the problem is that the sizes of "hello.obj" and "hello.pyd", generated by the bjam build, are very different: hello.obj: 766 kB hello.pyd: 13 kB In the manual build they are both large (~800 kB). If any further info is needed please tell me, and I'll see what I can do - but please be very specific, since I'm an absolute newbie in the world of boost, and not a very experienced programmer in general either. Regards \Sune Mai

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Re: [Boost-users] multi_index library, dynamic number of indices
by JOAQUIN LOPEZ MU?Z 13 Sep '06

13 Sep '06

Adán Cosgaya ha escrito: > Hi, I am using multi_index to keep a set of d-dimensional > points, where each point is a vector inside the multi_index > container. e.g (3,5,8,9,5) is a 5-dimensional point (but > this can vary and be 3-d, 7-d, etc..). I need to have the > set sorted by each of the dimensions. > > I can do it statically if I know in advance how many > dimensions I have, but I don't know how to make dynamic to > any number of dimensions. > > I currently have: > > template<int N> > struct nth_coordinate > { > typedef int result_type; > > int operator()(const vector<int>& x)const > { > return x[N]; > } > }; > > typedef multi_index_container< > vector<int>, > indexed_by< > sequenced<>, > ordered_non_unique<nth_coordinate<0> >, > ordered_non_unique<nth_coordinate<1> >, > ordered_non_unique<nth_coordinate<2> >, > ordered_non_unique<nth_coordinate<3> >, > ordered_non_unique<nth_coordinate<4> > > > > > multi_index_Points; > > is it possible do it without explicitly saying how many > indices do I need? Well, the short answer is no, you can't: multi_index_container is a compile-time construct, you cannot delay the specification to run time. That said, you can sort of have a kind of rudimentary dynamicity if you know the maximum number of coordinates and don't mind wasting memory and cpu cycles for those cases where the number of coordinates is less: rewrite nth_coordinate so as to not incur out of bounds accesses: template<int N> struct nth_coordinate { typedef int result_type; int operator()(const vector<int>& x)const { if(x.size()>N)return x[N]; else return 0; } }; and add as many indices to multi_index_Points as the maximum number of coordinates you know you're going to handle. > Also, I am trying to create a function which receives as a > parameter the dimension I want to work with, but it seems that > I need to explicitly say the number of the index in nth_index > (it obviously needs a constant). For example: > > int median (int d){ > ... > typedef multi_index_Points::nth_index< d >::type multi_index_Points_it; ===> I would like to pass "d" as a parameter > ... > } > > is there any workaround for this issues? Well, you're experiencing a typical clash between compile-time (or static) and run-time (or dynamic) polymorphisn. In the particular case of your median function, what you propose cannot work as is because multi_index_Points_it would be of a *different* type for each d! There are some techniques to bridge the static and dynamic worlds, all of them involving some sort of "type erasure", i.e. absorbing several different types into one polymorphic proxy type. The following is a possible realization of a dynamic median facility: class compile_time_median_table { private: template<int D> static int compile_time_median() { typedef typename multi_index_Points:: nth_index<D>::type multi_index_Points_it; ... } std::map<int,int (*)()> m; public: compile_time_median_table() { m[0]=compile_time_median<0>; ... m[6]=compile_time_median<6>; } int operator()(int d) { return m[d](); } }; int median(int d) { static compile_time_median_table t; return t(d); } Here, we perform the type erasure by storing a pointer to every different instantiation of compile_time_median<D> and using those within a proxy function int median(int) which provides the illusion of runtime polymorphism. Maybe this sort of approach does suit your needs. Best regards, Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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Newbie Jamfile author question
by Drumheller, Michael 13 Sep '06

13 Sep '06

Hello: I am trying to write some Jamfiles and I am finding that bjam tends to run my rules twice. Here is a tiny demo (using Boost 1.31.1 on Windows XP, with zsh/cygwin, bjam version "3.1.13. OS=NT".). % export BOOST_ROOT=c:/boost_1_33_1; cd c:/; rm -rf deleteme; mkdir deleteme; cd deleteme; echo 'Echo Hello Twice ;' > Jamfile; bjam Hello Twice Hello Twice ...found 8 targets... (Note: If the first statement is "export BOOST_ROOT=;" instead, I get the error "Unable to load Boost.Build: could not find "boost-build.jam...Attempted search from c:\deleteme up to the root...etc.") Notice the double-execution. Here is some potentially useful extra information. I ran it with -d5, and noticed that 'Echo Hello Twice ;' was getting executed at lines 1785 and 1797 of allyourbase.jam. Here is a snippet of the -d5 output: ---------------------------------------------------------output with -d5---------------------------------------------------------- <snip> c:\boost_1_33_1\tools/build/v1\allyourbase.jam:1784:>>>>|> set gINCLUDED_AS_DEPENDANT(Jamfile) = TRUE c:\boost_1_33_1\tools/build/v1\allyourbase.jam:1785:>>>>|> include Jamfile Jamfile:1:>>>>|> Echo Hello Twice Hello Twice c:\boost_1_33_1\tools/build/v1\allyourbase.jam:1791:>>>>|> set gIN_LIB_INCLUDE = c:\boost_1_33_1\tools/build/v1\allyourbase.jam:1796:>>>>|> set gINCLUDED(Jamfile) = TRUE c:\boost_1_33_1\tools/build/v1\allyourbase.jam:1797:>>>>|> include Jamfile Jamfile:1:>>>>|> Echo Hello Twice Hello Twice make -- all make -- all <snip> --------------------------------------------------------end output with -d5------------------------------------------------------ The file allyourbase.jam is too big for this email, but I'm including the relevant snippet here, with key lines marked with "<<<<<" : ------------------------------------------------------allyourbase.jam--- --------------------------------------------- <snip> # Load a user's Jamfile(s). # rule load-jamfiles ( jamfiles * ) { # First we load the Jamfiles without generation of main targets so that # dependencies are preloaded. Then we reload the files with target # generation enabled. local jamfile ; local as-dependant = $(gIN_LIB_INCLUDE) ; local gIN_LIB_INCLUDE ; gIN_LIB_INCLUDE = TRUE ; for jamfile-path in $(jamfiles) { if ! $(gINCLUDED_AS_DEPENDANT($(jamfile-path))) { gINCLUDED_AS_DEPENDANT($(jamfile-path)) = TRUE ; include $(jamfile-path) ; <<<<< line 1785 } } if ! $(as-dependant) { gIN_LIB_INCLUDE = ; for jamfile-path in $(jamfiles) { if ! $(gINCLUDED($(jamfile-path))) { gINCLUDED($(jamfile-path)) = TRUE ; include $(jamfile-path) ; <<<<< line 1797 } } } } <snip> ------------------------------------------------------end allyourbase.jam------------------------------------------------ Can anyone reproduce and/or explain this? Thank you. Michael Drumheller Boeing Phantom Works Mathematics and Engineering Analysis 425.373.2703 michael.drumheller(a)boeing.com This email may contain proprietary information. If you are not the intended recipient please delete it and notify the sender that you received it in error.

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multi_index library, dynamic number of indices
by Adán Cosgaya 13 Sep '06

13 Sep '06

Hi, I am using multi_index to keep a set of d-dimensional points, where each point is a vector inside the multi_index container. e.g (3,5,8,9,5) is a 5-dimensional point (but this can vary and be 3-d, 7-d, etc..). I need to have the set sorted by each of the dimensions. I can do it statically if I know in advance how many dimensions I have, but I don't know how to make dynamic to any number of dimensions. I currently have: template<int N> struct nth_coordinate { typedef int result_type; int operator()(const vector<int>& x)const { return x[N]; } }; typedef multi_index_container< vector<int>, indexed_by< sequenced<>, ordered_non_unique<nth_coordinate<0> >, ordered_non_unique<nth_coordinate<1> >, ordered_non_unique<nth_coordinate<2> >, ordered_non_unique<nth_coordinate<3> >, ordered_non_unique<nth_coordinate<4> > > > multi_index_Points; is it possible do it without explicitly saying how many indices do I need? Also, I am trying to create a function which receives as a parameter the dimension I want to work with, but it seems that I need to explicitly say the number of the index in nth_index (it obviously needs a constant). For example: int median (int d){ ... typedef multi_index_Points::nth_index< d >::type multi_index_Points_it; ===> I would like to pass "d" as a parameter ... } is there any workaround for this issues? would you mind pointing me in the right direction with an example of how to do it with thelibrary? thanks in advance... Adan

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RV: assign shared_ptr to 0 in initialization list
by Berenguer Blasi 13 Sep '06

13 Sep '06

Hi, I've been following this thread and been unable to do the same with: boost::shared_ptr< map<string,string> > () So I can't do: constructor ( boost::shared_ptr< map<string,string> > varName = boost::shared_ptr< map<string,string> > () ) The error I get is (why/how do I specify the missing params for map?): [cc] /home/bereng/blaseek/src/lib/cppToolkit/DBHelper.h:61: error: expected a,a or a...a before a>a token [cc] /home/bereng/blaseek/src/lib/cppToolkit/DBHelper.h:61: error: wrong number of template arguments (1, should be 4) [cc] /usr/lib/gcc/i386-redhat-linux/4.1.1/../../../../include/c++/4.1.1/bits/stl_ map.h:92: error: provided for atemplate<class _Key, class _Tp, class _Compare, class _Alloc> class std::mapa [cc] /home/bereng/blaseek/src/lib/cppToolkit/DBHelper.h:61: error: template argument 1 is invalid [cc] /home/bereng/blaseek/src/lib/cppToolkit/DBHelper.h:61: error: default argument missing for parameter 2 of aboost::shared_ptr<cppToolkit::ResultSet> cppToolkit::DBHelper::findObject(boost::shared_ptr<std::map<std::basic_strin g<char, std::char_traits<char>, std::allocator<char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > > >, std::string)a Thanks a lot in advance. -----Mensaje original----- De: boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org]En nombre de Scott Amort Enviado el: lunes, 14 de agosto de 2006 1:09 Para: boost-users(a)lists.boost.org Asunto: Re: [Boost-users] assign shared_ptr to 0 in initialization list Hi Scott, Thanks for the quick reply! On Sun, 2006-08-13 at 18:11 -0400, me22 wrote: > Instead of > > if (writer_.get() == 0) { /* create default error writer */ } > Why not just use > if ( !writer_ ) { /* create default error writer */ } > instead? This would work with ordinary pointers too. Thanks, that is clearer! > > What is the equivalent to: > > > > Parser testParser(0); > > > Parser testParser( ErrorWriterPtr() ); // would work > > I'd be tempted instead to replace the constructor definition with > Parser(ErrorWriterPtr writer = ErrorWritePtr()) > : writer_(writer) > { > } > however, to be able to just say > Parser testParser; > if you don't want to specify the writer. Perfect! Thanks again. Best, Scott _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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Re: [Boost-users] bind, and member function with a parameter
by Nat Goodspeed 13 Sep '06

13 Sep '06

> -----Original Message----- > From: boost-users-bounces(a)lists.boost.org [mailto:boost-users- > bounces(a)lists.boost.org] On Behalf Of Alexander Shyrokov > Sent: Wednesday, September 13, 2006 1:40 PM > To: boost-users(a)lists.boost.org > Subject: [Boost-users] bind, and member function with a parameter > > void animation::advance(int ms); > std::vector<animation> anims; > std::for_each(anims.begin(), anims.end(), > boost::bind(&animation::advance, _1, ms)); > > I am using boost::lambda:: before _1. I get an error error C2825: > 'F::result_type': cannot form a qualified name [Nat] boost::bind defines _1 (etc.) placeholders that you must use with boost::bind(). boost::lambda defines _1 (etc.) placeholders that you must use with boost::lambda::bind(). Sadly, the two sets of placeholders are incompatible. Might that be your problem? Try explicitly qualifying your placeholder: ... boost::bind::_1 ... If that works, then adjust your using clauses appropriately.

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[Regex] Japanese character equivalence is not working.
by Raveendra Madala 13 Sep '06

13 Sep '06

Hi, My name is Raveendra Madala. I work for Adobe Systems. We are using boost/regex 1.33.1 in one of our projects and we have encountered the following bug. Character Equivalence is supposed to find all variations of a given character. When we try to use this with Japanese characters regex is failing. To test this, if we have 0x30A2(Full width Katakana letter A), 0xFF71(Half width katakana letter A) and 0x32D0(Circled Katakana A) in the text and if we enter [[=a=]] where a is katakana a then regex is unable to find the three characters. This is just an example and is happening for all Japanese characters. How can we work around this issue? If you require more information on this, please do let me know. Thanks, Raveendra

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