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Boost-build targets order
by Jarosław Bober 19 Jan '12

19 Jan '12

Hello i have a quick question regarding targets in boost-build jamfiles. Let's say i have 3 targets defined in my jamroot and then I say: bjam target1 target2 target3 Is the order of building targets defined somehow? Regards

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boost::thread and helgrind
by Frederick Roth 19 Jan '12

19 Jan '12

I am currently fooling around with boost::thread. After writing a short example program (featuring boost::thread and boost::interprocess::interprocess_semaphore), I ran helgrind against it and got some "Possible data race" errors. The program does nothing but start two threads and serialize them via the semaphore and I am unsure whether a) I did some error I am not aware of b) helgrind reports false positives I would be glad if someone could look at my code (attached) and give me a hint. Frederick Roth PS: Software versions are boost-1.47.0, valgrind-3.6.1, gcc 4.6.2, c++0x

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Newbie, just starting.
by Robillard, Greg L 18 Jan '12

18 Jan '12

I am trying to get my boost libraries up and running, so I can start using the test framework. When running: #define BOOST_TEST_MODULE const_string test #include <boost/test/unit_test.hpp> // EOF I get the following error: xlC_r -I /home/.../BoostTest/boost_1_48_0 newTest.cpp -o newTest ld: 0711-317 ERROR: Undefined symbol: boost::unit_test::__vftQ3_5boost9unit_test15unit_test_log_tQ3_5boost9unit_test13test_observer ld: 0711-317 ERROR: Undefined symbol: .boost::unit_test::framework::master_test_suite() ld: 0711-317 ERROR: Undefined symbol: .main ld: 0711-345 Use the -bloadmap or -bnoquiet option to obtain more information. Alternately, when I try to run: #include <boost/lambda/lambda.hpp> #include <iostream> #include <iterator> #include <algorithm> int main() { using namespace boost::lambda; typedef std::istream_iterator<int> in; std::for_each( in(std::cin), in(), std::cout << (_1 * 3) << " " ); } I receive the following error: "/home/.../BoostTest/boost_1_48_0/boost/lambda/detail/function_adaptors.hpp", line 29.1: 1540-0063 (S) The text ">" is unexpected. Any assistance would be great. Greg

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boost::split_regex
by Brad Tilley 18 Jan '12

18 Jan '12

I'm experimenting with boost::split_regex and ran into an issue. The first three examples (results1, results2, results3) compile and work as expected. The last one (results4) does not compile. Here's the code I'm using: std::string str1("hello abc-ABC-aBc goodbye"); static const boost::regex re("-ABC-"); std::vector<boost::iterator_range<std::string::iterator> > results1; boost::ifind_all( results1, str1, "abc" ); std::vector<boost::iterator_range<std::string::iterator> > results2; boost::split(results2, str1, boost::is_any_of("-")); std::vector<std::string> results3; boost::split_regex(results3, str1, re); std::vector<boost::iterator_range<std::string::iterator> > results4; // compile error on this line: boost::split_regex(results4, str1, re); I've read the documents here: http://www.boost.org/doc/libs/1_48_0/doc/html/boost/algorithm/split_regex.h… and I believe my usage of split_regex is correct? It compiles and works with std::string (results3) but not with boost::iterator_range. The compiler error is long and verbose, so I'm hesitant to post it here. I was hoping that someone could look at the usage example I provided and see how I'm doing it wrong. I prefer iterator_range as it does not make a copy. Thanks for any advice! Brad

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Re: [Boost-users] how to calculate the Sample standard deviation using accumulators
by Victor Yankee 18 Jan '12

18 Jan '12

Hello Marshall, >On Jan 17, 2012, at 3:38 PM, Victor Yankee wrote: > >> How can I calculate the Sample Standard Deviation over a std::vector of doubles using accumulators? >> >>Or is there a faster way in boost math or some such? > > >Google is your friend (second hit for "boost accumulator standard deviation"): > http://stackoverflow.com/questions/7616511/calculate-mean-and-standard-devi… >and http://stackoverflow.com/questions/4316716/is-it-possible-to-use-boost-accu… > > > accumulator_set<double, stats<tag::variance> > acc; > for_each(a_vec.begin(), a_vec.end(), bind<void>(ref(acc), _1)); > > cout << mean(acc) << endl; > cout << sqrt(variance(acc)) << endl; But this is the POPULATION standard deviation (variance divided by N) I think. What I was asking for was how to calculated the SAMPLE standard deviation (variance devided by N-1). Thanks, Vic

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Re: [Boost-users] boost::asio::io_service::postand boost::asio::deadline_timer
by Marat Abrarov 18 Jan '12

18 Jan '12

Hi, Christopher. > I mean > now = current time > "Make biscuits 30 seconds from now." > "Clean the car 10 seconds from now." > "Ride your bike 45 seconds from now." > > Or does posting to the timer before it is "expired" interfere with the first > request? http://www.boost.org/doc/libs/1_48_0/doc/html/boost_asio/reference/basic_de… ~~~~~~~~~ Any pending asynchronous wait operations will be cancelled. The handler for each cancelled operation will be invoked with the boost::asio::error::operation_aborted error code. ~~~~~~~~~ Regards, Marat Abrarov.

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[graph] Query for interest: implicit de Bruijn graph
by Jeremiah Willcock 18 Jan '12

18 Jan '12

Would any Boost.Graph users be interested if I implemented an implicit de Bruijn graph? The graph would have the following benefits and drawbacks: - Would not use any storage, but would act as a d^k-vertex, d^(k+1)-edge (for alphabet size d and word length k) graph. - Would be exactly the de Bruijn graph (with no vertex merging or filtering); those features could be added on top, using filtered_graph and/or another wrapper layer. - A filtered_graph based on a sparse property map could "enable" vertices and edges to process in a given algorithm. - A separate layer could enable processing of chains of vertices together. - I could provide a reverse complement map for the base-4 case, as well as conversions between vertices and edges and strings of the correct length. If anyone is interested, I have a few questions as well: - What should the performance tradeoff be between accessing a vertex's incident edges vs. computing reverse complements? - Does the k-mer size (word length) need to be chosen at run-time, or would a compile-time setting be acceptable? -- Jeremiah Willcock

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Re: [Boost-users] [boost] Proposal for a Differential Evolution C++ library
by P Gregor 18 Jan '12

18 Jan '12

I could also help testing. regards, Piotr

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how to calculate the Sample standard deviation using accumulators Hello,
by Victor Yankee 18 Jan '12

18 Jan '12

Hello, How can I calculate the Sample Standard Deviation over a std::vector of doubles using accumulators? Or is there a faster way in boost math or somesuch? Thanks

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boost::asio::io_service::post and boost::asio::deadline_timer
by Christopher 18 Jan '12

18 Jan '12

I am getting boost:asio::error::operation_aborted error codes for an unknown reason in my handlers. No where did a cancel or reset occur, nor was the deadline_time or the io_service destroyed. Does anyone know if I may post to the same io_service a deadline_timer was constructed with or if they will interfere with eachother? May I post multiple times to the deadline timer calling back different methods? I can't imagine why the abort would show up other than I am taking something for granted.

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