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

regex again
by ninti＠internode.on.net 03 Jan '10

03 Jan '10

Sorry if this is double-posted, but my webmail has stripped angle brackets and their contents out of my previous email ... Boost 1.40 on CentOS 5.3 64bit: I have #included boost/regex.hpp in a file but get the following compile time error (mangled by webmail): /tmp/ccXM0HkR.o: In function `boost::basic_regex boost::cpp_regex_traits > >::assign(char const*, char const*, unsigned int)': contact.cpp:(.text._ZN5boost11basic_regexIcNS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEE6assignEPKcS7_j[boost::basic_regex boost::regex_traits > >::assign(char const*, char const*, unsigned int)]+0x27): undefined reference to `boost::basic_regex > >::do_assign(char const*, char const*, unsigned int)' collect2: ld returned 1 exit status The important bit appears to be 'undefined reference to boost__basic_regex' etc This file definitely exists at /usr/include/boost/regex.hpp. Another Boost #include in the same file (boost/date_time/posix_time/posix_time.hpp) produces no error. 'ldconfig -p' lists libboost_regex.so. What am I doing wrong? Thanks Mike

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[Accumulators] Evaluation of Expression Tree
by Horst S 02 Jan '10

02 Jan '10

Hello! Given an expression tree over mathematical expressions like 'sum', 'min', 'product', etc. and a fixed number of variables X1..Xn like the following, would it be possible to use BOOST Accumulators to re-evaluate the root evaluation function based on changes in the values of the variables efficiently? sum / \ / \ min product / \ / / \ X1 X2 X3 X4 Note that variables appear only as leaf nodes. Obviously, one can flatten the tree to the following expression: RootValue = sum( min(X1,X2), product(X2,X3,X4) ) Assuming that the current values of the variables are X1=3, X2=4, X3=2, X4=2 then RootValue evaluates to 19. Now setting X2=2 results in 10. The main objective is to minimize the cost of computing the value of the root evaluation function when changing the value of a subset of variables in X1..Xn. One can assume that the subset of variables that changes each time is rather small (typically only one) and the size of the expression tree is rather large. Are BOOST Accumulators a suitable way to model such kind of expressions and the corresponding incremental evaluation? Thanks!

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[boost] [program options] Recommended way to specify a list of strings
by Sanjit Jhala 01 Jan '10

01 Jan '10

Say I want to specify a list of servers via the boost program_options library. Something like: --total-servers N --server srv1 --server srv2 ... --server srvN How would I do this? It doesn't look like multitoken would work for this case, so would it be better for me to just have something like: --total-servers N --serverlist srv1 srv2 ... srvN and use a single string to store the serverlist and parse it myself? -Sanjit

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Strange issue with Serialization of BiMaps
by Mangal 01 Jan '10

01 Jan '10

Hi I am using Boost 1.40.0 and stlport 5.0 on Visual Studio 2008. The Bimap deserialization succeeds for 24 elements but starts failing after that. Here is the file with all the code #include "stdafx.h" #include <boost/archive/binary_oarchive.hpp> #include <boost/archive/binary_iarchive.hpp> #include <boost/functional/hash.hpp> #include <boost/bimap/bimap.hpp> #include <fstream> #include <exception> #include <iostream> using namespace boost; using namespace boost::bimaps; typedef unsigned int uint; struct GeoNode { public: GeoNode(){} GeoNode(uint x, uint y ): x_geocode(x), y_geocode(y) {} friend bool operator==(GeoNode const& a, GeoNode const& b) { return a.x_geocode == b.x_geocode && a.y_geocode == b.y_geocode; } friend std::size_t hash_value(GeoNode const& g) { std::size_t seed = 0; boost::hash_combine(seed, g.x_geocode); boost::hash_combine(seed, g.y_geocode); return seed; } friend bool operator < (GeoNode const& a, GeoNode const& b) { if (a.x_geocode != b.x_geocode) return a.x_geocode < b.x_geocode; return a.y_geocode < b.y_geocode; } friend std::ostream& operator << (std::ostream& os, const GeoNode& g) { os<<"X: "<<g.x_geocode<<" Y: "<<g.y_geocode<<std::endl; return os; } private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & x_geocode; ar & y_geocode; } public: uint x_geocode; uint y_geocode; }; template< class MapType > void print_map(const MapType & m) { typedef typename MapType::const_iterator const_iterator; for( const_iterator iter = m.begin(), iend = m.end(); iter != iend; ++iter ) { std::cout << iter->first << "-->" << iter->second << std::endl; } } int _tmain(int argc, _TCHAR* argv[]) { typedef bimap<uint, GeoNode> Store_type; const char* fileName = "Nodes.dat"; Store_type storeToWrite; Store_type storeThatsRead; int countThatWorks = 24; int countThatFails = 25; //insert Data for ( int i =0;i<countThatFails;++i) { storeToWrite.insert(Store_type::value_type(i, GeoNode(i+1, i+2))); } try { //write to file { std::ofstream ofs(fileName); boost::archive::binary_oarchive oa(ofs); oa << const_cast<const Store_type&> (storeToWrite); } //read from File { std::ifstream ifs(fileName); boost::archive::binary_iarchive ia(ifs); ia >> storeThatsRead; } print_map(storeThatsRead.left); } catch (std::exception e) { std::cout<<e.what(); } return 0; } An unknown exception is thrown when more than 24 elements are added. Tried to debug but right now can't make much sense. Any help is appreciated Thanks -- View this message in context: http://old.nabble.com/Strange-issue-with-Serialization-of-BiMaps-tp26983930… Sent from the Boost - Users mailing list archive at Nabble.com.

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