April 2008 - Boost-users - lists.preview.boost.org

Hide the predicate type of a filter_iterator?
by Jean-Pierre Bergamin 13 Apr '08

13 Apr '08

Hello everyone Imagine a class "numbers" that contains some values and methods like getEvenValues(), getOddValues(), getValuesLarger100() etc. Those methods return an iterator range of filter_iterators. In the the code I posted below, I'd have to define a different iterator_range of filter_iterator types for all the different methods (numbers::EvenFilterRange, numbers::OddFilterRange etc.). Is there some way to "hide" the type of the predicate used in a filter_iterator, so that it would be possible to have a generic "NumberRange" type for the return values of all methods? Something like: class numbers { typedef NumberRange ????; NumberRange getEvenValues() const; NumberRange getOddValues() const; NumberRange getValuesLarger100() const; } Thanks for your hints James /*********************************************/ #include <vector> #include <iostream> #include <boost/iterator/filter_iterator.hpp> #include <boost/iterator/counting_iterator.hpp> #include <boost/range/iterator_range.hpp> using namespace std; using namespace boost; /*********************************************/ template<typename T> struct is_even { bool operator()(const T &t) { return t % 2 == 0; } }; template<typename T> struct is_odd { bool operator()(const T &t) { return t % 2 != 0; } }; /*********************************************/ class numbers { public: typedef vector<int> NumberContainer; typedef NumberContainer::const_iterator NumberIter; typedef iterator_range< filter_iterator< is_even<numbers::NumberContainer::value_type>, NumberIter> > EvenFilterRange; numbers() { copy( counting_iterator<NumberContainer::value_type>(0), counting_iterator<NumberContainer::value_type>(100), back_inserter(m_vec) ); } template<typename Pred> iterator_range<filter_iterator<Pred, NumberIter> > getValues(const Pred &pred) { return make_iterator_range( make_filter_iterator(pred, m_vec.begin(), m_vec.end()), make_filter_iterator(pred, m_vec.end(), m_vec.end()) ); } EvenFilterRange getEvenValues() { typedef is_even<numbers::NumberContainer::value_type> PredType; PredType is_even_predicate; return getValues(is_even_predicate); }; private: NumberContainer m_vec; }; /*********************************************/ template<typename T> struct print_number { void operator()(const T &t) { cout << "Number: " << t << endl; } }; /*********************************************/ int main() { numbers n; numbers::EvenFilterRange even_filter_range = n.getEvenValues(); print_number<numbers::NumberContainer::value_type> printer; for_each(begin(even_filter_range), end(even_filter_range), printer); }

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Best way to share data in an object between two threads?
by boost＠celticblues.com 13 Apr '08

13 Apr '08

WinXP, Visual Studio 2003 I have a dialog based application which consists of the main thread and a data collection thread. The main thread updates a graph from data read by the data collection thread. I want to use an object, which is of type MyData to share the data between the threads. So , basically the data collection thread which collects data from a piece of hardware and places it in the MyData object, then the main thread reads from the MyData object and updates the graph. After reading a bit on shared memory, managed mapped memory etc. in Boost, I am a bit confused on how to do this. What is the best boost classes to use for this? Will I also need a sync object to synchronize the threads? Thanks, Ed

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Re: [Boost-users] [boost] [gil] [announcement] New IO lib
by Christian Henning 12 Apr '08

12 Apr '08

I'm sorry my link to the library needs a password. Instead, please use the following link: http://gil-contributions.googlecode.com/svn/trunk/gil_2/boost/gil/extension… > Is there any documentation yet? No, not yet. My announcement is all I have so far. I'll work on it. > > Definately get this added to the review queue. If nothing else it > will create lots > of interesting discussions. Nice work. I'll be using it. Thanks. I hope people will start a discussion. Christian

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(no subject)
by lolsson＠comhem.se 12 Apr '08

12 Apr '08

Hello! I'm having problems building boost 1.35 on a solaris machine with gcc 3.4.2. Pretty early on I get: gcc.compile.c++bin.v2/libs/test/build/gcc-3.4.2/release/threading-multi/debug.o /usr/ccs/bin/as: "/var/tmp//ccLNzYoL.s", line 3775: error: cannot use v8plus instructions in a non-v8plus target binary /usr/ccs/bin/as: "/var/tmp//ccLNzYoL.s", line 3815: error: cannot use v8plus instructions in a non-v8plus target binary ..... Here's some info about my system: $ uname -a SunOS se06pluto 5.8 Generic_117350-51 sun4u sparc SUNW,Sun-Fire-880 $ gcc -v Reading specs from /usr/local/lib/gcc/sparc-sun-solaris2.8/3.4.2/specs Configured with: ../configure --with-as=/usr/ccs/bin/as --with-ld=/usr/ccs/bin/ld --disable-nls --disable-libgcj --enable-languages=c, c++ Thread model: posix gcc version 3.4.2 I have found the following thread which seems to address my problem: http://www.nabble.com/-detail--sparc-v8plus-build-problem-td7944960.html After reading this I'm still unsure about what to do. Should I edit tools/build/v2/tools/gcc.jam and do something with one of these lines? # Sparc flags gcc OPTIONS <architecture>sparc/<address-model>32 : -m32 ; flags gcc OPTIONS <architecture>sparc/<address-model>64 : -m64 ; cpu-flags gcc OPTIONS : sparc : c3 : -mcpu=c3 : default ; cpu-flags gcc OPTIONS : sparc : v7 : -mcpu=v7 ; cpu-flags gcc OPTIONS : sparc : cypress : -mcpu=cypress ; cpu-flags gcc OPTIONS : sparc : v8 : -mcpu=v8 ; cpu-flags gcc OPTIONS : sparc : supersparc : -mcpu=supersparc ; cpu-flags gcc OPTIONS : sparc : sparclite : -mcpu=sparclite ; cpu-flags gcc OPTIONS : sparc : hypersparc : -mcpu=hypersparc ; cpu-flags gcc OPTIONS : sparc : sparclite86x : -mcpu=sparclite86x ; cpu-flags gcc OPTIONS : sparc : f930 : -mcpu=f930 ; cpu-flags gcc OPTIONS : sparc : f934 : -mcpu=f934 ; cpu-flags gcc OPTIONS : sparc : sparclet : -mcpu=sparclet ; cpu-flags gcc OPTIONS : sparc : tsc701 : -mcpu=tsc701 ; cpu-flags gcc OPTIONS : sparc : v9 : -mcpu=v9 ; cpu-flags gcc OPTIONS : sparc : ultrasparc : -mcpu=ultrasparc ; cpu-flags gcc OPTIONS : sparc : ultrasparc3 : -mcpu=ultrasparc3 ; Or is there something else I can do? Thanks, Lars

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[Graph] distance_map Property not working for DFS?
by Fonzi Chat 12 Apr '08

12 Apr '08

Hello, I just started using the Boost graph library a few days ago, so I am pretty new to all of this. What I'm trying to do is to record the path distance between a given source and target vertex using a variety of algorithms. So far, I've gotten BFS and Dijkstra's working correctly, however I'm having some trouble having distance information recorded in my distance_map Property when attempting to do this with DFS. For instance, this is what I wrote for Dijkstra's: dijkstra_shortest_paths(G, s, distance_map(&d[0]).visitor(*(new DijkstraVisitor(s, t)))); where G is a Graph, s is the start Vertex, d is defined as an integer vector and DijkstraVisitor is a class I have defined that is used as the visitor for the algorithm. Similarly, for DFS I have: depth_first_search(G, visitor(*(new DFSVisitor(s, t))).distance_map(&d[0]).root_vertex(s)); Unfortunately, when I try reading the d vector, all the values are zero and seem to have never been updated. My question is: what am I doing wrong and what can I do to record the distance correctly? Another somewhat related problem I have is that the algorithms seem to take VERY long to complete when larger graphs are processed. For instance, a graph with 100 vertices and 10,000 edges (mesh topology) takes about 10 minutes to complete the shortest path problem between two given vertices. Is this normal? Thank you for putting up with my amateur questions! Any and all help is appreciated. _________________________________________________________________ Get in touch in an instant. Get Windows Live Messenger now. http://www.windowslive.com/messenger/overview.html?ocid=TXT_TAGLM_WL_Refres…

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Help me for spirit grammar definition! It is simple...
by 钱晓明 11 Apr '08

11 Apr '08

I want to use spirit parsing some text file. The very basic element in those files is string, float and int. For example: 123L "hello" 987.4343 I wrote my grammar class: struct pm_parser : public grammar<pm_parser> { template <typename ScannerT> struct definition { definition(pm_parser const& self) { factor = int_p[show_int()]>>"L" | '"'>> *((~ch_p('"'))[show_char()]) >>'"' | real_p[show_double()] ; } rule<ScannerT> factor; rule<ScannerT> const& start() const { return factor; } }; }; show_int, show_char, show_double are structs used to show int, char and double value. When I parse 1L, it works. But when I parse 1, it is parsed twice(int_p and real_p are all works). How can I define grammar struct to parse text above without errors?

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Synchronized queue
by Yang Zhang 11 Apr '08

11 Apr '08

Hi, does boost provide a synchronized queue (or anything that is a concurrent producer-consumer abstraction)? Thanks!

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boost::algorithm + SunStudio + QuantLib
by Hicham Mouline 11 Apr '08

11 Apr '08

I extracted parts of QuantLib0.8.1 that I try to compile with CC on CC: Sun C++ 5.8 Patch 121017-13 2008/01/02 Studio11 i think The failure is in "dataparsers.cpp", line 86: Error: Could not find a match for std::string::basic_string(boost::transform_iterator<boost::algorithm::detail::to_lowerF<char>, const char*, boost::use_default, boost::use_default>, boost::transform_iterator<boost::algorithm::detail::to_lowerF<char>, const char*, boost::use_default, boost::use_default>) needed in boost::algorithm::to_lower_copy<std::string>(const std::string &, const std::locale&). the snippet from quantlib that uses this is : std::string sub = flist[i]; if (boost::algorithm::to_lower_copy(sub) == "dd") the function complained about from boost/algorithm/string/case_conv.hpp //! Convert to lower case /*! \overload */ template<typename SequenceT> inline SequenceT to_lower_copy( const SequenceT& Input, const std::locale& Loc=std::locale()) { return SequenceT( make_transform_iterator( begin(Input), detail::to_lowerF< typename value_type_of<SequenceT>::type >(Loc)), make_transform_iterator( end(Input), detail::to_lowerF< typename value_type_of<SequenceT>::type >(Loc))); } the same version of QL/boost compile ok on x86-64-linux/g++4.1 and win32-intel10 and other combinations any clues appreciated, regards,

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[iterator] Writable transform_iterator: how to?
by Nicola 11 Apr '08

11 Apr '08

Hello, I cannot figure out why the following code is wrong: #include <iostream> #include <vector> #include <functional> #include <boost/iterator/transform_iterator.hpp> struct f : public std::unary_function<int, int&> { int& operator()(int& x) { return x; } }; typedef std::vector<int> vec_type; typedef boost::transform_iterator<f, vec_type::iterator> trans_iter_type; int main() { vec_type V; V.push_back(4); trans_iter_type it(boost::make_transform_iterator(V.begin(), f())); std::cout << *it << std::endl; *it = 8; std::cout << *it << std::endl; return 0; } The compiler (g++ 4.0.1) complains about dereferencing and the error message says: error: passing ‘const f’ as ‘this’ argument of ‘int& f::operator()(int&)’ discards qualifiers Nicola

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[1.35.0][xpressive] INVALID_REGULAR_EXPRESSION - why?
by Markus Werle 11 Apr '08

11 Apr '08

Hi! The following piece of code used to compile with previous versions of boost: using namespace boost::xpressive; sregex path_delimiter = '/'; Now it bails out on VC8 SP1 with (beautified output): ------ Build started: Project: XXXX, Configuration: Release Win32 ------ Compiling... MainFrm.cpp MY_PATH_TO_BOOST\boost_1_35_0\boost/xpressive/proto/matches.hpp(356) : error C2825: 'Expr': must be a class or namespace when followed by '::' MY_PATH_TO_BOOST\boost_1_35_0\boost/xpressive/detail/static/grammar.hpp(317) : see reference to class template instantiation 'boost::proto::result_of::matches<Expr,Grammar>' being compiled with [ Expr=char, Grammar=boost::xpressive::Grammar<char> ] MY_PATH_TO_BOOST\boost_1_35_0\boost/mpl/if.hpp(63) : see reference to class template instantiation 'boost::xpressive::is_valid_regex<Expr,Char>' being compiled with [ Expr=char, Char=char ] MY_PATH_TO_BOOST\boost_1_35_0\boost/xpressive/basic_regex.hpp(94) : see reference to class template instantiation 'boost::mpl::if_<T1,T2,T3>' being compiled with [ T1=boost::xpressive::is_valid_regex<char,char>, T2=boost::mpl::true_, T3=boost::xpressive::INVALID_REGULAR_EXPRESSION ] .\MainFrm.cpp(1514) : see reference to function template instantiation 'boost::xpressive::basic_regex<BidiIter>::basic_regex<char>(const Expr &)' being compiled with [ BidiIter=std::_String_const_iterator<char,std::char_traits<char>, std::allocator<char>>, Expr=char ] MY_PATH_TO_BOOST\boost_1_35_0\boost/xpressive/proto/matches.hpp(356) : error C2143: syntax error : missing ',' before '`global namespace'::proto_base_expr' MY_PATH_TO_BOOST\boost_1_35_0\boost/xpressive/proto/matches.hpp(356) : error C2977: 'boost::proto::detail::matches_impl' : too many template arguments MY_PATH_TO_BOOST\boost_1_35_0\boost/xpressive/proto/matches.hpp(260) : see declaration of 'boost::proto::detail::matches_impl' MY_PATH_TO_BOOST\boost_1_35_0\boost/xpressive/proto/matches.hpp(357) : error C2955: 'boost::proto::detail::matches_impl' : use of class template requires template argument list MY_PATH_TO_BOOST\boost_1_35_0\boost/xpressive/proto/matches.hpp(260) : see declaration of 'boost::proto::detail::matches_impl' MY_PATH_TO_BOOST\boost_1_35_0\boost/xpressive/basic_regex.hpp(94) : error C2664: 'boost::mpl::assertion_failed' : cannot convert parameter 1 from 'boost::mpl::failed ************boost::xpressive::INVALID_REGULAR_EXPRESSION::* ***********' to 'boost::mpl::assert<false>::type' No constructor could take the source type, or constructor overload resolution was ambiguous MY_PATH_TO_BOOST\boost_1_35_0\boost/xpressive/basic_regex.hpp(95) : error C2514: 'boost::xpressive::is_valid_regex<Expr,Char>' : class has no constructors with [ Expr=char, Char=char ] Build What went wrong? Changing the code to sregex path_delimiter = sregex::compile("/"); fixes the issue for me, but I missed this change in the release notes ... Markus

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