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Re: [Boost-users] Using <boost/math/distributions/non_central_t.hpp> gives unexpected error
by Neil Nelson 02 Aug '12

02 Aug '12

gcc-3.8 is referenced on the net in posts early in 2005. Looks like the latest MinGW release http://sourceforge.net/projects/mingw/files/MinGW/Base/gcc/Version4/gcc-4.6… has gcc-4.6. The latest MinGW release could assist in a variety of areas including this one. Neil Nelson

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Using <boost/math/distributions/non_central_t.hpp> gives unexpected error
by Avinash K. Hathiramani 02 Aug '12

02 Aug '12

Hello, I am new to using the Boost libraries and I was very happy to see that there is a non-central t distribution class in Boost (I have not managed to find this anywhere else). Unfortunately I am not able to use this without getting an error. Here is my code: #include <boost/math/distributions/non_central_t.hpp> using namespace std; double nu = 3.0; double delta = 3.0; double x = 3.0; boost::math::non_central_t_distribution<double> nct(delta, nu); double test_pdf = pdf(nct, x); double test_cdf = cdf(nct, x); cout << "Probability density of Student's t is " << test_cdf << endl; cout << "Cumulative probability of Student's t is " << test_cdf << endl; This does not give any results and if I put in an error catch here, I get the following message: "Error in function boost::math::gamma_p_derivative<e>(e, e): numeric overflow". I do not follow what is going wrong and I am able to get results for both the CDF and PDF with the same parameters from MATLAB (and an on-line calculator which I found for this distribution), so I do not think that the parameters are invalid. I would be grateful if anyone can advise me as to whether I am doing anything incorrectly here. I apologise in advance if I have missed anything obvious, or unintentionally broken any of the discussion policies (it is my first time posting on this forum). Thank you in advance for your help. Kind regards, Avinash

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Re: [Boost-users] [boost] [type_erasure] Review ends today July 27, 2012
by Hossein Haeri 02 Aug '12

02 Aug '12

Hi Dave, > 1. Type erasure is Java's only answer for genericity, which is bad for > performance. > > 2. Java does all its type erasure one object at a time, which leads to > the dreaded binary method problem. Well, these, AFAICU, make a distinctive difference. And, the distinction doesn't stop here: For example, Java's type erasure has a nasty effect on overload resolution too. > Steven's library supports something a lot more like Haskell's > implementation of generics. Which is why I suggested calling it "staged typing"/"deferred typing". Cheers, --Hossein

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Announce: Boost 1.50 installer for 32-bit Windows now available
by John Wiegley 01 Aug '12

01 Aug '12

With apologies to the community for not finding the time to release Windows installers for 1.48 and 1.49, we now have an installer for 1.50 available for immediate download: http://www.boostpro.com/download The version installs 32-bit libraries and/or DLLs for the following compilers: Visual C++ 8.0 (Visual Studio 2005) Visual C++ 9.0 (Visual Studio 2008) Visual C++ 10.0 (Visual Studio 2010) We are dropping support for Visual C++ 7.1 as of this time, unless someone wishes to contract us to bring it back. Also, although I have prepared a 64-bit installer, I have not yet found a solution for integrating it with the existing installer. If anyone with NSIS scripting experience would be willing to assist me, we'd be happy to provide a free installer which installs both 32-bit and 64-bit Boost libraries for applicable Windows platforms. Enjoy! -- John Wiegley BoostPro Computing Software Development Training http://www.boostpro.com Clang/LLVM/EDG Compilers C++ Boost

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boost::filesystem question
by Arno 01 Aug '12

01 Aug '12

Hi all, is it possible to find out the Windows short name of a valid Windows path and/or vise versa? We are using Boost 1.42 at the moment. best regards Arno

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[fusion] for_each with indices
by Agustín K-ballo Bergé 01 Aug '12

01 Aug '12

I recently needed to iterate over a fusion sequence, calling a function for each element that depends not only on the element type but on its index (position within the sequence) as well. I didn't find anything readily available to use in conjunction with for_each, so I ended up using fold with the index as state. However, I would like to get the index as a compile time value. What would be the simpler/best way to do this? Creating an iterator adaptor that keeps track of advances to the base iterator (should I be using the iterator_facade extension mechanism)? Or perhaps zipping the sequence with some kind of infinite mpl::vector_c sequence? Agustín K-ballo Bergé.- http://fusionfenix.com

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Pool memory and std::forward_list
by Claude 01 Aug '12

01 Aug '12

Hi! I would create a memory pool for the node of a C++11 forward_list. It is possible use the BOOST pool memory with std::forward_list? -- View this message in context: http://boost.2283326.n4.nabble.com/Pool-memory-and-std-forward-list-tp46338… Sent from the Boost - Users mailing list archive at Nabble.com.

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Segfault when using date_time
by Sara Siegal 01 Aug '12

01 Aug '12

I attempted to rebuild my Boost installation with nanosecond support for the date-time library. I did so by adding BOOST_DATE_TIME_POSIX_TIME_STD_CONFIG = 1 ; to boost-build.jam and adding <define>BOOST_DATE_TIME_POSIX_TIME_STD_CONFIG to the jamfile in date_time/build. However, when I add this code to my application and compile, it segfaults: boost::posix_time::time_duration time1, time2; time1=boost::posix_time::seconds(3); std::cout << boost::posix_time::to_simple_string(time1) << std::endl; time2=boost::posix_time::nanoseconds(987654321); std::cout << boost::posix_time::to_simple_string(time2) << std::endl; boost::this_thread::sleep(time2); The segfault is at /archive/home/ssiegal/test/include/boost/date_time/posix_time/posix_time_config.hpp:99: (gdb) list 94 { 95 typedef gregorian::date date_type; 96 typedef time_duration time_duration_type; 97 simple_time_rep(date_type d, time_duration_type tod) : 98 day(d), 99 time_of_day(tod) 100 { 101 // make sure we have sane values for date & time 102 if(!day.is_special() && !time_of_day.is_special()){ 103 if(time_of_day >= time_duration_type(24,0,0)) { Anyone else ever see this? Is there anything else I need to do to turn on nanosecond resolution? Thanks very much!

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[boost] [type_erasure] Review ends today July 27, 2012
by Lorenzo Caminiti 01 Aug '12

01 Aug '12

Hello all, On Mon, Jul 23, 2012 at 9:09 AM, Lorenzo Caminiti <lorcaminiti(a)gmail.com> wrote: > On Wed, Jul 18, 2012 at 1:13 AM, Lorenzo Caminiti <lorcaminiti(a)gmail.com> wrote: >> *** The review of Steven Watanabe's proposed Boost.TypeErasure library >> begins on July 18, 2012 and ends on July 27, 2012. *** > > *** Boost.TypeErasure review ends in 5 days. Please submit your reviews :D *** *** Boost.TypeErasure review ends today July 27, 2012. If you are planning to submit a review, please do so as soon as possible. *** Thank you to everyone who has commented on the library and submitted a review so far! The review manager, --Lorenzo P.S. I am considering extending the review until end of day Sunday July 29, 2012... I will keep you posted. > There have been interesting discussions on the library on the ML but I > have not received any official review yet :( Especially if you are a > user of Boost Any, Function, and Any Iterator, you definitely want to > take a look at Type Erasure as it generalizes solutions provided by > those other libraries. > > Thank you. > > The review manager. > --Lorenzo > >> THE LIBRARY >> >> C++ provides runtime polymorphism through virtual functions. They are >> a very useful feature, but they do have some limitations. >> * They are intrusive. In generic programming, we can design an >> interface which allows third-party types to be adapted to it. >> * They require dynamic memory management. Of course, most of the >> problems can be avoided by using an appropriate smart pointer type. >> Even so, it still acts like a pointer rather than a value. >> * Virtual functions' ability to apply multiple independent concepts to >> a single object is limited. >> The Boost.TypeErasure library solves these problems allowing us to >> mirror static generic programming at runtime. >> >> Library source: >> http://svn.boost.org/svn/boost/sandbox/type_erasure/ >> >> Pre-built documentation: >> http://steven_watanabe.users.sourceforge.net/type_erasure/libs/type_erasure/ >> >> You can also download archives with pre-built documentation from: >> http://sourceforge.net/projects/steven-watanabe.u/files/ >> >> YOUR REVIEW >> >> Please submit a review to the mailing-list by replying to this email >> ("[boost] [type_erasure] Review ..." should be in the subject). >> >> Please state clearly whether you think this library should be accepted >> as a Boost library. >> >> Other questions you may want to consider: >> 1. What is your evaluation of the design? >> 2. What is your evaluation of the implementation? >> 3. What is your evaluation of the documentation? >> 4. What is your evaluation of the potential usefulness of the library? >> 5. Did you try to use the library? With what compiler? Did you have >> any problems? >> 6. How much effort did you put into your evaluation? A glance? A >> quick reading? In-depth study? >> 7. Are you knowledgeable about the problem domain? >> >> Thanks in advance to all who participate in the review discussion -- >> I'm looking forward to it!

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[Boost.Move] Conflict between std::move and boost::move (Boost 1.49.0)
by Jonathan Jones 01 Aug '12

01 Aug '12

Hi folks, Consider the following code (which distilled from a real world example): #include <boost/move/move.hpp> #include <boost/optional/optional.hpp> #include <utility> #include <vector> typedef boost::optional<int> data_type; typedef std::vector<data_type> vector_type; vector_type func() { vector_type vv; return move(vv); } If I compile this code using Boost 1.49 on Visual Studio 2010, or on a recent version of g++ (e.g. 4.7.1) which supports some C++11 features, the code fails to compile, complaining about ambiguity between std::move and boost::move. Strangely, the code compiles fine with Apple Clang version 3.1. Is there a way to work around the compilation problem which doesn't involve explicitly qualifying the calls to move? I'd prefer to use argument-dependent-lookup. Removing the includes of boost/move.hpp is not possible. In the real world example, that header is included indirectly. I did notice that if I define the macro BOOST_MOVE_USE_STANDARD_LIBRARY_MOVE, the compilation errors disappear. Is this the correct approach for compilers which support std::move? I find it odd that this macro isn't already defined for such compilers. Thanks in advance! Jon

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