May 2010 - Boost-users - lists.boost.org

[BGL] Upper limits on graph size
by Adam Spargo 20 May '10

20 May '10

Hi, I am working on genome assembly software and hope that the BGL can save me a lot of development time, but before I make the investment in learning the library can somebody advise me on whether it is appropriate. My initial test sets will be quite small. However in the end I will want to scale up to on the order of a billion nodes, quite sparsely connected. We have the RAM and many CPUs, but will the code scale up this far? Thanks in advance, Adam. -- Dr Adam Spargo High Performance Assembly Group email: aws(a)sanger.ac.uk Wellcome Trust Sanger Institute Tel: +44 (0)1223 834244 x7728 Hinxton, Cambridge CB10 1SA Fax: +44 (0)1223 494919 -- The Wellcome Trust Sanger Institute is operated by Genome Research Limited, a charity registered in England with number 1021457 and a company registered in England with number 2742969, whose registered office is 215 Euston Road, London, NW1 2BE.

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[MPL] what is my base class?
by John Dlugosz 20 May '10

20 May '10

I'm writing a class template, say C<T>, that has essentially different features depending on a classification of type T. So, I implemented Ca and Cb as befitting the two categories, and then make that transparent to the user by making a stub for C that inherits from either of those two, using boost::mpl::if_ to choose between them. However, the constructors have to be brought down manually. To "inherit" them, they need to be forwarded to the base class: C (...args...) : Ca (...args...) {} The problem is, I can't easily name the base class here in the base initialization list. I'm not even sure repeating the if_ metaexpression here would work, since the init list doesn't even like typedefs but wants the literal name of the class. Did I paint myself into a corner? Please help. TradeStation Group, Inc. is a publicly-traded holding company (NASDAQ GS: TRAD) of three operating subsidiaries, TradeStation Securities, Inc. (Member NYSE, FINRA, SIPC and NFA), TradeStation Technologies, Inc., a trading software and subscription company, and TradeStation Europe Limited, a United Kingdom, FSA-authorized introducing brokerage firm. None of these companies provides trading or investment advice, recommendations or endorsements of any kind. The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material from any computer.

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[BGL] Graph of an Iterator
by Hossein Haeri 20 May '10

20 May '10

Dear all, Is there any way to deduce the graph a graph-iterator is iterating over? So, for example for: typedef graph_type::vertex_iterator iterator; iterator begin, end; tie(begin, end) = vertices(g); is there anything like graph_type gg = graph_of(begin); so that gg == g? TIA, --Hossein

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Re: [Boost-users] [BGL] VertexProperties as a Nested Type
by Hossein Haeri 20 May '10

20 May '10

Dear Jeremiah, > It looks like property_map is the right name. Could > you please post the entire file so I know which line numbers > those errors are referring to? Sure. Please find that in the attachments. TIA, --Hossein

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[regex] validating expressions
by Jeff Flinn 20 May '10

20 May '10

Is this the correct way to validate a regex expression? bool validateExpression(std::string e) { using namespace boost; return !expression.empty() && !regex(e, regex_constants::no_except).empty(); } This passes all of my existing unit tests except for the following strings which boost::regex reports as valid. "[[[A-Z]]" "[A-Z]??" Both Qt's QRegExp and http://www.regexplanet.com/simple/index.html report the first is invalid. Qt's QRegExp reports the second as invalid, while http://www.regexplanet.com/simple/index.html report it as valid. Is boost::regex right or remiss? Is there a better on line regex validator? Thanks, Jeff

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unable to build boost graph 1.43 with gcc 3.4.5
by Vial, Florent 20 May '10

20 May '10

Hi, trying to build boost 1.43 with gcc 3.4.5, i obtain following error: "g++" -ftemplate-depth-128 -O3 -finline-functions -Wno-inline -Wall -pthread -m64 -fPIC -DBOOST_ALL_NO_LIB=1 -DNDEBUG -I"." -I"libs/graph/src" -c -o "/tmp/boost_143.build.gcc34/boost/bin.v2/libs/graph/build/gcc-3.4.5/rele ase/address-model-64/link-static/threading-multi/graphml.o" "libs/graph/src/graphml.cpp" ./boost/property_tree/detail/xml_parser_read_rapidxml.hpp: In function `void boost::property_tree::xml_parser::read_xml_internal(std::basic_istream<t ypename Ptree::key_type::value_type, std::char_traits<typename Ptree::key_type::value_type> >&, Ptree&, int, const std::string&) [with Ptree = boost::property_tree::basic_ptree<std::string, std::string, std::less<std::string> >]': ./boost/property_tree/xml_parser.hpp:52: instantiated from `void boost::property_tree::xml_parser::read_xml(std::basic_istream<typename Ptree::key_type::value_type, std::char_traits<typename Ptree::key_type::value_type> >&, Ptree&, int) [with Ptree = boost::property_tree::ptree]' libs/graph/src/graphml.cpp:49: instantiated from here ./boost/property_tree/detail/xml_parser_read_rapidxml.hpp:108: error: non-constant `(((int)f_c) | 3072)' cannot be used as template argument ./boost/property_tree/detail/xml_parser_read_rapidxml.hpp:108: error: no matching function for call to `rapidxml::xml_document<char>::parse(char*)' ...skipped <p/tmp/boost_143.build.gcc34/boost/bin.v2/libs/graph/build/gcc-3.4.5/rel ease/address-model-64/link-static/threading-multi>libboost_graph-mt.a(cl ean) for lack of <p/tmp/boost_143.build.gcc34/boost/bin.v2/libs/graph/build/gcc-3.4.5/rel ease/address-model-64/link-static/threading-multi>graphml.o... ...skipped <p/tmp/boost_143.build.gcc34/boost/bin.v2/libs/graph/build/gcc-3.4.5/rel ease/address-model-64/link-static/threading-multi>libboost_graph-mt.a for lack of <p/tmp/boost_143.build.gcc34/boost/bin.v2/libs/graph/build/gcc-3.4.5/rel ease/address-model-64/link-static/threading-multi>graphml.o... ...skipped <pstage/lib>libboost_graph-mt.a for lack of <p/tmp/boost_143.build.gcc34/boost/bin.v2/libs/graph/build/gcc-3.4.5/rel ease/address-model-64/link-static/threading-multi>libboost_graph-mt.a... ...failed updating 1 target... any workaround coming to mind ? Thank you, Florent Arnold & Richter Cine Technik GmbH & Co. Betriebs KG Sitz: Munchen - Registergericht: Amtsgericht Munchen - Handelsregisternummer: HRA 57918 Personlich haftender Gesellschafter: Arnold & Richter Cine Technik GmbH Sitz: Munchen - Registergericht: Amtsgericht Munchen - Handelsregisternummer: HRB 54477 Geschaftsfuhrer: Franz Kraus; Dr. Martin Prillmann A new star is born - ALEXA the most versatile digital camera system. Get all the latest information from arridigital.com and YouTube.

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boost::lambda::bind - how to address the member variable in the expression?
by Archie14 20 May '10

20 May '10

Example: struct A { int i; }; class C { public: void store(int i); }; boost::ptr_vector<A> lst; C c; std::for_each (lst.begin(), lst.end(), boost::lambda::bind(&C::store, c, boost::lambda::_1.i)); Question: construct boost::lambda::_1.i is invalid. I understand why it is so, but can't find a way to reference member variable in this case. Any advise or referral to the specific paragraph in boost::lambda documentation is appreciated. Thanks.

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[regex] function to escape regex control characters like QRegExp::escape?
by Jeff Flinn 20 May '10

20 May '10

Is there a function to escape regex control characters like RegExp::escape already in boost::regex or perhaps boost::expressive? Thanks, Jeff

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Boost::Spirit problem
by Xavier Pegenaute 20 May '10

20 May '10

Hi, I have a problem converting "const boost::phoenix::actor<boost::spirit::argument<0> >&" to int, anyone know how I can do it?, looking in the documentation seems it should work as it is, but it does not ..., any idea? PD: Find attached a simple example of the problem. Thanks a lot. Xavi.

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[iostreams]Can I write data directly to the device of a stream?
by Comet 20 May '10

20 May '10

Hi, I assumed that stream wrote data directly to it's associated device, but after a few tests I found I was wrong. I wrote this code snippet: <--- Code ---> int main() { using namespace std; using namespace boost::iostreams; string src; src.assign(10 * 1024, 'a'); size_t size = src.size(); // ContainerDevice is from boost::iostreams::example typedef ContainerDevice<std::vector<char> > MyDevice; vector<char> container; string str; container.reserve(size); str.reserve(size); for (size_t i = 0; i < 1000000; ++i) { // Version 1 MyDevice device(container); stream<MyDevice> io(device); io.write(src.c_str(), src.size()); io.flush(); container.clear(); // Version 2 #if 0 str.insert(str.end(), src.begin(), src.end()); container.insert(container.end(), str.begin(), str.end()); str.clear(); container.clear(); #endif } return 0; } <--- Code-End ---> The first version(write data to the device by stream) is slower than the second(copy data, then copy again to device), so I guess stream do some unnecessary copy operations (eg: copy data to inner buffer, then copy again from buffer to device). I tried replacing stream<MyDevice> io(device); with stream<MyDevice> io(device, 0, 0); to set inner buffer size to 0, but the result was much more slower. I set a breakpoint at ContainerDevice::write(const char_type* data, std::streamsize n) then found n passed was always 1, which means every call wrote only 1 byte. If there is a way to write data directly to the device, my program will be very efficient. thanks.

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