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[gsoc18]project1-1: Add statistics and machine learning functions
by SheldonZhang 02 Mar '18

02 Mar '18

Hi, My name is Zhang Bohan(Sheldon Zhang) from China. I am a freshman in Beijing University of Posts and Telecommunications, majoring in Information and Communication Engineering. I want a mentor who can guide me to accomplish the project. I am interested in working for Boost.uBLAS because in my profession there are plenty of calculation about matrix. I believe this will lead me to better understanding about it. And I love machine learning, it is the way to the future. I am taking a machine learning course(taught by Andrew Ng) on coursea. So I know what I am going to do in the project. I do quite well in Linear Algebra. In the exam, I got top 10% in the grade. I have been programming since junior high school. I am familiar to C++-11 and its features(like lambdas and template). I have good command of basic algorithms. I participated in National Olympiad in Informatics and got good grades. Besides, I am a teaching assistant in Program Designing Course. I am googd at English, so there is few difficulty in communicating. I have done the programming competency test https://github.com/ltg001/gsoc18-codeCompetencyTest At last, what should I do in this period? With regard, Sheldon Zhang -- Sent from: http://boost.2283326.n4.nabble.com/Boost-Dev-f2600599.html

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[gsoc18] [Boost.Real] Competency Test
by Parth Mittal 02 Mar '18

02 Mar '18

Hi My name is Parth Mittal, and I'm a third year computer science undergraduate. Here is my attempt at the competency test: (wrt the first, second, and third bullet on the project page) 1. I uploaded my code here (https://github.com/parthmittal/boost_competency_test) I'm not sure how much of it is required to be functional but (of course) I can write more code if required. The current code uses an std::pair of the chosen rational type to represent intervals, it is probably more sensible to replace this with a dedicated type for intervals. Also I have two different ideas for dealing with integers in the binary operators: (i) Wrap them into a "real" number (with an approximation function that always returns the exact value and an error term of 0). (ii) Add a facility for additive and multiplicative rational factors to the class. 2. For sure there is no way to be sure two numbers are equal in finite time, so while checking if a and b are equal, we should pass an integer parameter, say K, and then for every pair of integers i, j between 1 and K, we should check if a(i) = b(j) (of course a(i) = b(j) iff the intervals share a point). This feels somewhat inefficient (it would be nice to eliminate the quadratic runtime with K), but since we don't have a guarantee that a(i + 1) is a subset of a(i), I don't see any obvious way to improve this. 3. To be honest, I had to google for "Small String Optimization" - and the analogue I can see is to store as an array the values of a(k) for all k <= K for some small constant K. I'm not sure how to implement this at compile time; it makes sense that the approximation function(s) for the real number involved be constexpr, but I've never written any code which is constexpr. Perhaps my code in (1) already makes this clear, but I'm not very experienced at writing C++; I've written probably 100k+ lines while doing programming contests, but this was rather simple code which was written once and read never. I can fill in the gaps in my knowledge of the language on an ad-hoc basis (or using the time until the SoC officially begins). Thank you for reading Parth Mittal

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Boost Performance
by Ian Kosen 01 Mar '18

01 Mar '18

Hi, I was looking at this benchmark https://github.com/mloskot/spatial_index_benchmark <https://github.com/mloskot/spatial_index_benchmark> which attempts to compare the performance between Boost and LibSpatialIndex. It caught my eye that Boost was magnitudes faster than LibSpatialIndex. Is there an obvious reason for this? Design considerations and trade offs? Thank you :) Regards, Kosen

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[teeks99-09-p-win2016-64on64][poly_collection] Regression with latest MSVC 14.1 in C++17 mode
by Joaquin M López Muñoz 28 Feb '18

28 Feb '18

Hi, MSVC 14.1 (_MSC_FULL_VER=191225834) in C++17 mode (_MSVC_LANG=201704L) is having a regression when compiling Boost.PolyCollection tests: http://www.boost.org/development/tests/develop/developer/output/teeks99-09-… The problem happens in this seemingly innocent context (https://github.com/boostorg/poly_collection/blob/654018c7ce14674a1c0527206a… ): template< typename ForwardIterator1,typename ForwardIterator2,typename Predicate > bool operator()( ForwardIterator1 first1,ForwardIterator1 last1, ForwardIterator2 first2,Predicate pred)const { ... using difference_type= typename std::iterator_traits<ForwardIterator1>::difference_type; difference_type l1=std::distance(first1,last1); // syntax error (wrongly) signalled here Is there some kind soul with access to this compiler who'd like to try the following workarounds and report the results? // workaround 1 using difference_type= typename std::iterator_traits<ForwardIterator1>::difference_type; typename difference_type l1=std::distance(first1,last1); // workaround 2 typedef typename std::iterator_traits<ForwardIterator1>::difference_type difference_type; difference_type l1=std::distance(first1,last1); Thank you! Joaquín M López Muñoz

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request for comments in a new format library
by Roberto Hinz 28 Feb '18

28 Feb '18

Dear boost community, some time ago I announced a format library I'm working on. I think at that time it was still too incipient for one to evaluate whether it looked promising, thought some few but very useful observation were made ( one regarding i18n and other code bloat ) that made me change many things. Now the library is more evolved and I think it will be ready for review somewhere in the second half of this year, if no big change happens. This is a c++14 text format library with some unique features: - designed to be utf8 friendly - easy to extend for new destination types ( like some different string type ) - able to align (justify) a set of sub-arguments as one ( see joins <https://robhz786.github.io/stringify/doc/html/special_input_types/special_i…> ) - it enables the use of translations tools ( like gettext ), yet the formatting is not specified by a format string. And the problem with format strings that they lead to run time errors (instead of compilation error ) when they are incorrect. Hence I much appreciate any comments, especially if can identify any flaw I didn't realize. repo: https://github.com/robhz786/stringify doc: https://robhz786.github.io/stringify/doc/html/ best regards roberto

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Re: [boost] [Boost-bugs] [Boost C++ Libraries] #13458: 'cl' is not recognized as an internal or external command, operable program or batch file. Failed to build Boost.Jam build engine. Please consult bjam.log for furter diagnostics.
by Andrew Depke 28 Feb '18

28 Feb '18

It looks like you're missing "cl.exe" on your system, or have not included it in your PATH. cl.exe, as seen here <https://msdn.microsoft.com/en-us/library/f35ctcxw.aspx>, is Microsoft's C++ compiler, which can be obtained by downloading the latest version of Visual Studio. Downloading and installing MSVS will automatically place it in your PATH. On Tue, Feb 27, 2018 at 2:28 PM, Boost C++ Libraries < noreply(a)lists.boost.org> wrote: > #13458: 'cl' is not recognized as an internal or external command, > operable program > or batch file. Failed to build Boost.Jam build engine. Please consult > bjam.log for furter diagnostics. > ------------------------------+--------------------- > Reporter: anonymous | Owner: (none) > Type: Bugs | Status: new > Milestone: To Be Determined | Component: None > Version: Boost 1.41.0 | Severity: Problem > Keywords: | > ------------------------------+--------------------- > 'cl' is not recognized as an internal or external command, > operable program or batch file. > > Failed to build Boost.Jam build engine. > Please consult bjam.log for furter diagnostics. > > -- > Ticket URL: <https://svn.boost.org/trac10/ticket/13458> > Boost C++ Libraries <http://www.boost.org/> > Boost provides free peer-reviewed portable C++ source libraries. > > _______________________________________________ > Boost-bugs mailing list > Boost-bugs(a)lists.boost.org > https://lists.boost.org/mailman/listinfo.cgi/boost-bugs > >

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[release] 1.67.0 closed for major changes
by Daniel James 28 Feb '18

28 Feb '18

The master branch is now closed for major changes and will be closed for the beta in a week. Also, you can also add your libraries' changes to the release notes at: <https://github.com/boostorg/website/blob/master/feed/history/boost_1_67_0.q…> Remember that after editing the file, you need to submit the form to create a pull request. You can preview the release notes at: <http://www.boost.org/users/history/in_progress.html> Thanks, -- The Boost Release Team

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Boost managed_shared_memory not working with C's mmap call on freeBSD
by vijay sharma 27 Feb '18

27 Feb '18

Hi All, I am having two processes and they are sharing shared-memory. - Process-1 (implemented in c++ and using boost::interprocess::managed_shared_memory interface) - Process-2 (implemented in c and using "she_open" and "mmap" interfaces) This code was working fine on Linux But When I deployed same code on FreeBSD. Process-2 (C lang based) is keep on throwing error in mmap. Error is "Bad file Descriptor". Please let me know: 1. Do I need to change the interface while moving from Linux to FreeBSD. 2. Is there any known issue with this design. Code Snippet: Process-1(c++): obj = new boost::interprocess::managed_shared_memory( boost::interprocess::open_or_create,<shm_name>, <shm_size>); // to create shm obj->allocate(<data_size>) ; // to write in shm Process-2 (c): int fd = shm_open(<shm_name>,O_RDWR, 0666);void * startpoint = mmap(NULL, <shm_size>, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); // using the startpoint to read data written by process-1. Boost version: Boost.1.63.0 I have raised same on stackoverflow.com and below is the link: https://stackoverflow.com/questions/48984703/boost-managed-shared-memory-no… Thanks, Vijay

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[Boost][CMake] Status of cmake support.
by Mike 26 Feb '18

26 Feb '18

Hi everyone, since I couldn't find any official information about that, I wanted to ask if there is any new information about the cmake support in boost (since the initial discussion on the ml after the steering committee's announcement)? Is there some agreement on how to do the transition or at least a popular formal/informal proposal? Is there any place to track which libraries can already be built with cmake? What is the best way for a non library authors like me to help with the transition? IIRC there was talk about a cmake library some time ago, but I haven't heard anything about that in a long time. Is such a library even desired/necessary? Imho getting all of boost to compile with cmake should be pretty simple, but if this is expected to happen in a transparent manner (same output, same workflow including test result upload), a fair bit of boost knowledge, cmake skills and support machinery might be required. Best regards Mike

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[winapi] Bumping default target to Windows 7?
by Andrey Semashev 26 Feb '18

26 Feb '18

Hi, I was thinking about bumping the default target Windows version to 7 in Boost.WinAPI. The current default is Vista, which EOLed in April 2017. There is not much difference from the available API standpoint (in Boost.WinAPI this would enable a few constants related to process management), but there may be some interesting extensions that could be useful to libraries. Note that this will not preclude targeting older Windows versions, just as it doesn't preclude targeting XP or 2000 now. Users will still be able to specify the target Windows version as they can now. Note also that I'm not planning this for 1.67, only 1.68. Any objections/thoughts?

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