June 2010 - Boost-users - lists.preview.boost.org

[multi_array] Generalizing the iterators?
by Geoff Hilton 29 Jun '10

29 Jun '10

How feasible would generalizing the iterators used by multi_array be, for use by any typical array (eg. std::vector<T> or T*?) type? I know I would love that!

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Re: [Boost-users] Extracting items from a string
by José Tomás Tocino García 29 Jun '10

29 Jun '10

Hello. > I have a string of the following format: > > 11, 0, 1461, 400 > > I need to be able to extract any element of the string at any point, so for > example, the 1, would return 11, or the second world return 0. What is the > best way of extracting any individual element, without using any temporary > variables. > > IF I use boost.tokenizer, can I access any element individually, without > using iterators? Or is there a better way of dealing with this sort of > string. Looks like you want to have a vector with the tokenized elements. I'm afraid the only way of getting the results of a tokenizing operation is via iterators. However, you can easily assign the elements to a vector: #include<iostream> #include<boost/tokenizer.hpp> #include<boost/foreach.hpp> #include<string> #include <vector> int main(){ using namespace std; using namespace boost; string s = "This is, a test"; tokenizer<> tok(s); vector <string> myTokens (tok.begin(), tok.end()); BOOST_FOREACH(string & s, myTokens){ cout << s << endl; } } Hope it helps. -- José Tomás Tocino García

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Re: [Boost-users] Extracting items from a string
by Steven Watanabe 29 Jun '10

29 Jun '10

AMDG Sean Farrow wrote: > I have a string of the following format: > > 11, 0, 1461, 400 > > I need to be able to extract any element of the string at any point, so > for example, the 1, would return 11, or the second world return 0. What is > the best way of extracting any individual element, without using any > temporary variables. > > IF I use boost.tokenizer, can I access any element individually, without > using iterators? Or is there a better way of dealing with this sort of > string. > If you can't parse the string into a more suitable data structure, then you can't avoid searching from the beginning of the string on each access. Probably the easiest way is std::string element = *boost::next(make_token_iterator(...), n); In Christ, Steven Watanabe

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Extracting items from a string
by Sean Farrow 29 Jun '10

29 Jun '10

Hi: I have a string of the following format: 11, 0, 1461, 400 I need to be able to extract any element of the string at any point, so for example, the 1, would return 11, or the second world return 0. What is the best way of extracting any individual element, without using any temporary variables. IF I use boost.tokenizer, can I access any element individually, without using iterators? Or is there a better way of dealing with this sort of string. Any help appreciated. Cheers Sean.

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[ptr_container] Abstract Key type in ptr_map<Key, Val> impossible?
by Mikhail Levin 29 Jun '10

29 Jun '10

Hello, The following code would not compile. struct Key { bool operator<(const Key&) const; virtual void blah() const = 0; }; struct Val { /* */ }; boost::ptr_map<Key, Val> map; Although boost::ptr_set<Key> set; seems to work.

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bounded_buffer, Checking if full
by Lloyd 29 Jun '10

29 Jun '10

Hi, I am using a bounded_buffer to solve a producer consumer problem. When the producer produces more data than the buffer can hold, how can I know that the buffer is full?or does it throw some exception when trying to push more data to it? I have gone through the documentation, but could not find a way... Thanks, Lloyd ______________________________________ Scanned and protected by Email scanner

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compiling parallel boost graph library (PBGL)
by Elzbieta Krepska 29 Jun '10

29 Jun '10

Dear PBGL developers, I'm getting errors when compiling parallel-bgl-0.7.0 (the release from PBGL website). I'm compiling against boost 1.43.0, MPI implementation by MX (mpich/mx/gcc/64/1.2.7..3) and using gcc version 3.4.6 20060404 (Red Hat 3.4.6-11). The error I'm getting is: ---- boost/graph/distributed/betweenness_centrality.hpp:574: error: using invalid field `boost::graph::parallel::detail::betweenness_centrality_delta_stepping_impl <Graph, DistanceMap, IncomingMap, EdgeWeightMap, PathCountMap>::owner' ---- and apparently happens during linking. I would appreciate your help. I put the printout from 'make' (verbosity on so that you can see the failing command) and my CMakeCache temporarily under: http://www.cs.vu.nl/~ekr/pbgl-error/error.txt http://www.cs.vu.nl/~ekr/pbgl-error/CMakeCache.txt Best regards, Elzbieta Krepska -- Elzbieta Krepska, ekr(a)cs.vu.nl Vrije Universiteit, Amsterdam Faculty of Exact Sciences Dept. of Computer Science De Boelelaan 1081 1081 HV Amsterdam, The Netherlands Phone: +31 (0)20 59 87 562 http://www.cs.vu.nl/~ekr

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[Spirit] parse tree node does not get produced with Single character input.
by Philippe forest 29 Jun '10

29 Jun '10

Hi, First of all I would like to state that spirit = str_p("very") >> +ch_p(' ') >>( str_p("nice") | str_p("cool") | str_p("greate") ) >> +ch_p(' ') >> str_p("parser") ; So Thanks for that. But I do face a problem. When assigning ID to nodes of the parse tree. ex: rule<ScannerT, parser_context<>, parser_tag<stringID> > String; I've attached a sample to demonstrate the problem. In short: The grammar below does not produce a parse tree node with a 'stringID' when the input is a single character 'a'. As soon as I have 2 or more characters 'aa' then I get a node stringID. definition( ExpressionNoStringIDGrammar const& /*self*/) { Char = ch_p('a') ; String = ( +Char ) ; language = String ; } rule<ScannerT, parser_context<>, parser_tag<charID> > Char; rule<ScannerT, parser_context<>, parser_tag<stringID> > String; rule<ScannerT> language; BUT: If I remove the 'Char' parser and substitute it with ch_p('a') then it works fine , then I always get a node stringID even with a single input char. definition( ExpressionNoStringIDGrammar const& /*self*/) { String = ( +ch_p('a') ) ; language = String ; } rule<ScannerT, parser_context<>, parser_tag<charID> > Char; rule<ScannerT, parser_context<>, parser_tag<stringID> > String; rule<ScannerT> language; Could anyone either explain me what is going on ? - I'm I doing something wrong or is this a bug or works as designed ? Thanks Again Phil.

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boost MPI error , MPI_ERR_TRUNCATE: message truncated
by Jack Bryan 29 Jun '10

29 Jun '10

Dear All, I am using boost MPI and mpirun (Open MPI) 1.3.4 I got error: terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::mpi::exception> >' what(): MPI_Test: MPI_ERR_TRUNCATE: message truncated I installed boost MPI library and compile and run the program by openMPI. It seems that the message has been truncated by the receiver. How can I fix the problem ? Is it a bug of OpenMPI ? Any help is appreciated. Jack June 28 2010 _________________________________________________________________ The New Busy think 9 to 5 is a cute idea. Combine multiple calendars with Hotmail. http://www.windowslive.com/campaign/thenewbusy?tile=multicalendar&ocid=PID2…

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O'Reillly OSCON
by Robert Ramey 28 Jun '10

28 Jun '10

http://www.oscon.com/oscon2010 Are any boosters expecting to attend this conference and/or exhibition. Are their any who live in the area who might be interested but need a good reason to attend? Attending the exhibits only is free. Anyone who plans to visit and want's to undertake a mission for boost should contact me via private email at ramey at rrsd.com Robert Ramey

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