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

[MPI] Test Processor Counts
by Belcourt, Kenneth 14 May '10

14 May '10

Hi, While running the trunk tests, we've found that occasionally the system load average jumps up over 100 and occasionally hits 200. As you can imagine for 8 to 32 core systems, this adversely impacts users on those systems. The issue is that I'm running the trunk tests in parallel, usually -j8 to -j32 and when the MPI tests run, we run into the high load problem. Some of the MPI tests run up to 17 processors so the combination of parallel testing and large processor count tests cause this issue. Now the high load average may last for only 5 to 15 minutes or so but this is enough to trigger a sysadmin question asking what I'm up. I'm looking for a solution that wouldn't require significantly reducing testing throughput. Possible solutions might include serializing the execution of the MPI tests using something like the link-semaphore in Boost.Build, reducing the processor counts of the MPI tests, only running the larger tests on unchecked or unknown MPI implementations, setting up an MPI machine file to run the MPI tests off of the local system that built the executable, etc... Any other ideas on how to manage this? Thanks. -- Noel

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Re: [Boost-users] Boost-users Digest, Vol 2359, Issue 1
by Mauricio Gomes 14 May '10

14 May '10

Hi Harmut, Did you uncomment the line: //#include <boost/spirit/include/qi_no_skip.hpp> ? It is commented out in the code below. If I include this line, compilation fails. You also have to check optimizations because the code below is not using no_skip[] in the grammar so there is a chance that a smart compiler that is not in debug mode might ignore the non-used code. In my case I am in debug mode, no optmizations and including the qi_no_skip.hpp header suffices to get the error. Thanks for your attention ! 1. Re: Spirit: parsing tab separated values and no_skip > compilation error. (Hartmut Kaiser) > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 13 May 2010 18:28:19 -0500 > From: "Hartmut Kaiser" <hartmut.kaiser(a)gmail.com> > To: <boost-users(a)lists.boost.org> > Subject: Re: [Boost-users] Spirit: parsing tab separated values and > no_skip compilation error. > Message-ID: <0d5301caf2f3$fa1c64e0$ee552ea0$(a)gmail.com> > Content-Type: text/plain; charset="iso-8859-1" > > > I am a beginner with Spirit. I just read the tutorial and I am playing > > around with some examples. > > Environment: boost 1.43, Windows Vista, Code::Blocks, mingw, gcc 4.5. > > > > My goal is to build a tab separated values parser. > > If you have an example on how to parse something like: > > string/t/tdouble/tdouble > > it would be great. Contiguous tabs should be considered as one tab, not > an > > empty field. > > > > To start I just tried to parse a tab separated list of strings but I am > > having some difficulties. > > > > Is there another skip parser to be used instead of space (for full code > > see the end of the message below) ? > > I have changed the commas to tabs in the code below but it failed. I > guess > > it was because it was skipping them (space skipper). > > > > ??????? bool r = phrase_parse(first, last, > > > > ??????????? //? Begin grammar > > ??????????? ( > > ??????????????? +(char_ - ',') % ',' > > ??????????? ) > > ??????????? , > > ??????????? //? End grammar > > > > ??????????? space, v); > > > > This code works with commas but it fails with '\t'. > > > > I tried to use no_skip[] but it failed to compile the header #include > > <boost/spirit/include/qi_no_skip.hpp>: > > > > C:\boost_1_43_0\boost\spirit\home\qi\directive\no_skip.hpp|30|error: > > 'no_skip' is not a member of 'boost::spirit::tag'| > > > > For full error message see the end of the message below. > > > > Any suggestions ? > > > > Thank you for your attention, > > Mau. > > > > #include <boost/config/warning_disable.hpp> > > #include <boost/spirit/include/qi.hpp> > > #include <boost/spirit/include/phoenix_core.hpp> > > #include <boost/spirit/include/phoenix_operator.hpp> > > #include <boost/spirit/include/phoenix_stl.hpp> > > //#include <boost/spirit/include/qi_no_skip.hpp> > > > > #include <iostream> > > #include <string> > > #include <vector> > > > > #define VECTOR_TYPE std::string > > > > namespace client > > { > > ??? namespace qi = boost::spirit::qi; > > ??? namespace ascii = boost::spirit::ascii; > > > > ??? > ////////////////////////////////////////////////////////////////////// > > ///// > > ??? //? Our number list compiler > > ??? > ////////////////////////////////////////////////////////////////////// > > ///// > > ??? //[tutorial_numlist4 > > ??? template <typename Iterator> > > ??? bool parse_numbers(Iterator first, Iterator last, > > std::vector<VECTOR_TYPE>& v) > > ??? { > > ??????? using qi::double_; > > ??????? using qi::phrase_parse; > > ??????? using qi::_1; > > ??????? using ascii::space; > > ??????? using qi::char_; > > > > ??????? bool r = phrase_parse(first, last, > > > > ??????????? //? Begin grammar > > ??????????? ( > > ??????????????? +(char_ - ',') % ',' > > ??????????? ) > > ??????????? , > > ??????????? //? End grammar > > > > ??????????? space, v); > > > > ??????? if (first != last) // fail if we did not get a full match > > ??????????? return false; > > ??????? return r; > > ??? } > > ??? //] > > } > > > > > ////////////////////////////////////////////////////////////////////////// > > // > > //? Main program > > > ////////////////////////////////////////////////////////////////////////// > > // > > int > > main() > > { > > ??? std::cout << > > "/////////////////////////////////////////////////////////\n\n"; > > ??? std::cout << "\t\tA comma separated list parser for Spirit...\n\n"; > > ??? std::cout << > > "/////////////////////////////////////////////////////////\n\n"; > > > > ??? std::cout << "Give me a comma separated list of numbers.\n"; > > ??? std::cout << "The numbers will be inserted in a vector of numbers\n"; > > ??? std::cout << "Type [q or Q] to quit\n\n"; > > > > ??? std::string str; > > ??? while (getline(std::cin, str)) > > ??? { > > ??????? if (str.empty() || str[0] == 'q' || str[0] == 'Q') > > ??????????? break; > > > > ??????? std::vector<VECTOR_TYPE> v; > > ??????? if (client::parse_numbers(str.begin(), str.end(), v)) > > ??????? { > > ??????????? std::cout << "-------------------------\n"; > > ??????????? std::cout << "Parsing succeeded\n"; > > ??????????? std::cout << str << " Parses OK: " << std::endl; > > > > ??????????? for (std::vector<VECTOR_TYPE>::size_type i = 0; i < v.size(); > > ++i) > > ??????????????? std::cout << i << ": " << v[i] << std::endl; > > > > ??????????? std::cout << "\n-------------------------\n"; > > ??????? } > > ??????? else > > ??????? { > > ??????????? std::cout << "-------------------------\n"; > > ??????????? std::cout << "Parsing failed\n"; > > ??????????? std::cout << "-------------------------\n"; > > ??????? } > > ??? } > > > > ??? std::cout << "Bye... :-) \n\n"; > > ??? return 0; > > } > > This example compiles fine for me (VC10, g++ 4.5). Is it supposed to fail? > > Regards Hartmut > > --------------- > Meet me at BoostCon > www.boostcon.com > > > > >

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[signals] What's special about iterators passed to combiners?
by Boris Schaeling 14 May '10

14 May '10

A reader of my book noticed that the sample program at http://en.highscore.de/cpp/boost/src/4.2.8/main.cpp which uses a combiner to return the smallest value of all slot values is buggy. The combiner's implementation is rather simple as iterators are simply forwarded to std::min_element(): template <typename T> struct min_element { typedef T result_type; template <typename InputIterator> T operator()(InputIterator first, InputIterator last) const { return *std::min_element(first, last); } }; As simple as the implementation is: This combiner does not return the smallest value but always the value the first iterator refers to (at least with VC++ 2008 and g++ 4.2.1). This can be easily tested by swapping the return values of the two functions func1() and func2() in the sample program. First I was trying to find a fix - temporarily copying the values to a container is all what is needed: T operator()(InputIterator first, InputIterator last) const { std::vector<T> v(first, last); return *std::min_element(v.begin(), v.end()); } Then I was trying to understand what's special about the iterators. Please look at the following code and guess whether the values printed will be different or not: T operator()(InputIterator first, InputIterator last) const { InputIterator temp = first; ++first; std::cout << *first << std::endl; std::cout << *temp << std::endl; } If you think you get two different values then you'll be as surprised as I am: Both iterators temp and first return the second value in the range [first, last). I can't find any explanation in the Boost.Signals documentation. I wouldn't be surprised though if this is a known issue because there is a sample combiner called maximum used (see http://www.boost.org/doc/libs/1_43_0/doc/html/signals/tutorial.html#id17304…) which doesn't use an algorithm from the C++ standard (I guess intentionally?). Anyway: Is this a bug? If it isn't is there a recommended work-around (apart from temporarily copying values to a container)? Then it's probably not safe to use any C++ standard algorithm in combiners? Could this be added to the FAQ or anywhere else in the Boost.Signals documentation? Boris

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[Boost.Units] quantity<unit> problem with template specialisation algorithm?
by Thomas Shorrock 14 May '10

14 May '10

Hello, many thankyous to the developers of Boost.Units and Boost libraries generally, I have been using them for a few years now and this is my first difficulty. I have been having some problems when using template specialisation (g++ 4.4.3) with Boost.Units (Boost 1_42_0). When calling a specialised template function I have found that I need to be very careful with the argument, In short, specialised_templated_function(1.0 * boost::units::si::metre) works fine specialised_templated_function(1 * boost::units::si::metre) specialised function is not found (default tried) This caught me out for a while and so I thought I would report it in case it is a small bug. If this is not a Boost issue then my appologies. In detail, here is the code to reproduce: #include <iostream> #include <boost/units/systems/si.hpp> namespace bu = boost::units; /** Convert arbitrary units into seconds * When a distance is provided, the speed parameter is used to calculate the time. * Otherwise the speed variable is ignored. */ template<class unit> bu::quantity<bu::si::time> any2second(const unit& t, const bu::quantity<bu::si::velocity>& speed =1*bu::si::meters_per_second) { return bu::quantity<bu::si::time>(t); } /* Specialisations for quantity<length> */ template<> bu::quantity<bu::si::time> any2second(const bu::quantity<bu::si::length>& d, const bu::quantity<bu::si::velocity>& speed) { return bu::quantity<bu::si::time>(d / speed); } int main() { //The following use the default function and work fine std::cout<<"any2second(1.0*s) = "<<any2second(1.0*bu::si::second)<<std::endl; std::cout<<"any2second(1*s) = "<<any2second(1*bu::si::second)<<std::endl; //The following uses the specialised function and works fine std::cout<<"any2second(1.0*m) = "<<any2second(1.0*bu::si::metre, 1*bu::si::meters_per_second)<<std::endl; //The following tries to use the defualt function rather than the specialisation. //It does not compile because (correctly) a metre cannot be converted into a second. //std::cout<<"any2second(1*m) = "<<any2second(1*bu::si::metre, 1*bu::si::meters_per_second)<<std::endl; return 0; } Many thanks, Tom The Institute of Cancer Research: Royal Cancer Hospital, a charitable Company Limited by Guarantee, Registered in England under Company No. 534147 with its Registered Office at 123 Old Brompton Road, London SW7 3RP. This e-mail message is confidential and for use by the addressee only. If the message is received by anyone other than the addressee, please return the message to the sender by replying to it and then delete the message from your computer and network.

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[date_time] how to generate a random date?
by Saygin Arkan 14 May '10

14 May '10

Hi, Does boost's date provide a random date generation? Or somehow should I generate my own date and then pass as a parameter? date GeneratorUtils::getRandomDate() { int year, month ,day; day = 1 + rand() % 29; month = 1 + rand() % 11; year = 1980 + rand() % 25; date d(year, month, day); return d; } currently this is my implementation, but sometimes it returns invalid month value. terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::gregorian::bad_day_of_month> >' what(): Day of month is not valid for year Probably because of something like 29th Feb or sth like that. I rarely saw that exception. I could modify the code easiy but I just wanted to know that if such a functionality exists? Thanks a lot, I've started to adore boost after uuid & date =) -- Saygin

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[proto, fusion] Segfault in for_each
by David A. Greene 14 May '10

14 May '10

I'm using boost 1.42. As part of a proto transform, I am flattening an expression tree of comma operators and sending it to fusion::transform followed by fusion::for_each, something like this: for_each(transform(flatten(expr), func1), func2) I am getting a segmentation fault in for_each. func1 does not appear to be invoked. Program output: Building type list: comma( comma( function( terminal(int_) , terminal(32) ) , function( terminal(float_) , terminal(32) ) ) , function( terminal(int_) , terminal(16) ) ) 3 items Program received signal SIGSEGV, Segmentation fault. 0x0804d52d in boost::proto::result_of::child_c<Builder::Wrapper<boost::proto::exprns_::expr<boost::proto::tag::comma, boost::proto::argsns_::list2<Builder::Wrapper<boost::proto::exprns_::expr<boost::proto::tag::function, boost::proto::argsns_::list2<Builder::Wrapper<boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<Builder::keyword::int_>, 0l> > const&, Builder::Wrapper<boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<int const&>, 0l> > >, 2l> > const&, Builder::Wrapper<boost::proto::exprns_::expr<boost::proto::tag::function, boost::proto::argsns_::list2<Builder::Wrapper<boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<Builder::keyword::float_>, 0l> > const&, Builder::Wrapper<boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<int const&>, 0l> > >, 2l> > const&>, 2l> > const&, 0l>::call (e=...) at /usr/include/boost/proto/traits.hpp:1544 (gdb) print e $1 = (const Builder::Wrapper<boost::proto::exprns_::expr<boost::proto::tag::comma, boost::proto::argsns_::list2<Builder::Wrapper<boost::proto::exprns_::expr<boost::proto::tag::function, boost::proto::argsns_::list2<Builder::Wrapper<boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<Builder::keyword::int_>, 0l> > const&, Builder::Wrapper<boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<int const&>, 0l> > >, 2l> > const&, Builder::Wrapper<boost::proto::exprns_::expr<boost::proto::tag::function, boost::proto::argsns_::list2<Builder::Wrapper<boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<Builder::keyword::float_>, 0l> > const&, Builder::Wrapper<boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<int const&>, 0l> > >, 2l> > const&>, 2l> > &) @0x0: <error reading variable> Note the null expression reference. fusion::distance on a begin/end pair from the same sequence works as expected so I believe the sequence is at least well-formed. I've been wrestling with this for days. Any ideas on how to debug this? Thanks! -Dave

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Spirit: parsing tab separated values and no_skip compilation error.
by Mauricio Gomes 13 May '10

13 May '10

Hi, I am a beginner with Spirit. I just read the tutorial and I am playing around with some examples. Environment: boost 1.43, Windows Vista, Code::Blocks, mingw, gcc 4.5. My goal is to build a tab separated values parser. If you have an example on how to parse something like: string/t/tdouble/tdouble it would be great. Contiguous tabs should be considered as one tab, not an empty field. To start I just tried to parse a tab separated list of strings but I am having some difficulties. Is there another skip parser to be used instead of space (for full code see the end of the message below) ? I have changed the commas to tabs in the code below but it failed. I guess it was because it was skipping them (space skipper). bool r = phrase_parse(first, last, // Begin grammar ( +(char_ - ',') % ',' ) , // End grammar space, v); This code works with commas but it fails with '\t'. I tried to use no_skip[] but it failed to compile the header #include <boost/spirit/include/qi_no_skip.hpp>: C:\boost_1_43_0\boost\spirit\home\qi\directive\no_skip.hpp|30|error: 'no_skip' is not a member of 'boost::spirit::tag'| For full error message see the end of the message below. Any suggestions ? Thank you for your attention, Mau. #include <boost/config/warning_disable.hpp> #include <boost/spirit/include/qi.hpp> #include <boost/spirit/include/phoenix_core.hpp> #include <boost/spirit/include/phoenix_operator.hpp> #include <boost/spirit/include/phoenix_stl.hpp> //#include <boost/spirit/include/qi_no_skip.hpp> #include <iostream> #include <string> #include <vector> #define VECTOR_TYPE std::string namespace client { namespace qi = boost::spirit::qi; namespace ascii = boost::spirit::ascii; /////////////////////////////////////////////////////////////////////////// // Our number list compiler /////////////////////////////////////////////////////////////////////////// //[tutorial_numlist4 template <typename Iterator> bool parse_numbers(Iterator first, Iterator last, std::vector<VECTOR_TYPE>& v) { using qi::double_; using qi::phrase_parse; using qi::_1; using ascii::space; using qi::char_; bool r = phrase_parse(first, last, // Begin grammar ( +(char_ - ',') % ',' ) , // End grammar space, v); if (first != last) // fail if we did not get a full match return false; return r; } //] } //////////////////////////////////////////////////////////////////////////// // Main program //////////////////////////////////////////////////////////////////////////// int main() { std::cout << "/////////////////////////////////////////////////////////\n\n"; std::cout << "\t\tA comma separated list parser for Spirit...\n\n"; std::cout << "/////////////////////////////////////////////////////////\n\n"; std::cout << "Give me a comma separated list of numbers.\n"; std::cout << "The numbers will be inserted in a vector of numbers\n"; std::cout << "Type [q or Q] to quit\n\n"; std::string str; while (getline(std::cin, str)) { if (str.empty() || str[0] == 'q' || str[0] == 'Q') break; std::vector<VECTOR_TYPE> v; if (client::parse_numbers(str.begin(), str.end(), v)) { std::cout << "-------------------------\n"; std::cout << "Parsing succeeded\n"; std::cout << str << " Parses OK: " << std::endl; for (std::vector<VECTOR_TYPE>::size_type i = 0; i < v.size(); ++i) std::cout << i << ": " << v[i] << std::endl; std::cout << "\n-------------------------\n"; } else { std::cout << "-------------------------\n"; std::cout << "Parsing failed\n"; std::cout << "-------------------------\n"; } } std::cout << "Bye... :-) \n\n"; return 0; } Error messages when compiling with the no_skip include file: C:\boost_1_43_0\boost\spirit\home\qi\directive\no_skip.hpp|30|error: 'no_skip' is not a member of 'boost::spirit::tag'| C:\boost_1_43_0\boost\spirit\home\qi\directive\no_skip.hpp|30|error: 'no_skip' is not a member of 'boost::spirit::tag'| C:\boost_1_43_0\boost\spirit\home\qi\directive\no_skip.hpp|30|error: template argument 2 is invalid| C:\boost_1_43_0\boost\spirit\home\qi\directive\no_skip.hpp|36|error: 'boost::spirit::no_skip' has not been declared| C:\boost_1_43_0\boost\spirit\home\qi\directive\no_skip.hpp|37|error: 'boost::spirit::no_skip_type' has not been declared| C:\boost_1_43_0\boost\spirit\home\qi\directive\no_skip.hpp|79|error: 'no_skip' is not a member of 'boost::spirit::tag'| C:\boost_1_43_0\boost\spirit\home\qi\directive\no_skip.hpp|79|error: 'no_skip' is not a member of 'boost::spirit::tag'| C:\boost_1_43_0\boost\spirit\home\qi\directive\no_skip.hpp|79|error: template argument 1 is invalid| ||=== Build finished: 8 errors, 0 warnings ===| -- Mauricio Gomes Pensar Digital 55-11-9698-1683 (Brazil - mobile)

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How do I do reverse routing?
by Stephen Woodbridge 13 May '10

13 May '10

Hi all, A Dijkstra solution builds the tree outward from a source node. Is there and easy was to change the sense of the route so the calculated result is based on a tree inward to the a sink node? Is there an example of this anywhere? I could not find one. Thanks, -Steve

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metafunction question
by John Dlugosz 13 May '10

13 May '10

A co-worker mentioned an interesting issue. I thought some metaprogramming, or at least more advanced insight into STL, might apply here. Consider a class derived from an STL collection. It features a special find(x) function that works with his search criteria. It returns an iterator into the collection. There are two forms needed: iterator find(x); const_iterator find(x) const; and the annoying part is that they contain exactly the same code. The implementation uses the inherited iterators and collection features to do the finding. The larger question is, is there a better way to approach that? The immediate question is, my thought of using a template helper requires the return type to be determined based on the constness of the incoming parameter for the collection type. Is there a handy metafunction for that already in existance? --John -silly company footer automatically added, sorry. 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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Re: [Boost-users] How can I use random library in a class? Can any one with kindness help me?
by Pete Bartlett 13 May '10

13 May '10

>Can anyone tell me why? You need to initialize the base class, not the base class's members. So: class Usedchild:public Used{ public: Usedchild(Matrix inputmatrix, Vec inputvec):Used(inputmatrix,inputvec){}; }; should work. It may also be worth your while to look at a text on C++ syntax before diving too deep into the complicated parts of Boost.

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