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[poly_collection] Small review
by Pete Bartlett 11 May '17

11 May '17

> > Dear Ion, Joaquin and boost mailing list, > > I hope this brief review is of some value to you. I don’t expect to be a recognised name on the mailing list but have contributed to it intermittently over the years. I have also used the author’s MultiIndex library in production for about a decade. > > I would recommend that PolyCollection be accepted into Boost. > > I think the design pattern is common enough to be Boost-ified. I have done something very similar to boost::base_collection myself in the past and have achieved useful speed ups over a solution like boost::ptr_vector in a production system. My speed-ups were not quite as good as Joaquin documents, but I can’t tell if this was due to the ineptitude of my own solution or due to lab conditions of the Boost.PolyCollection tests. > > I spent a couple of hours reading the docs and running basic examples on my default compiler (VS2015 x64) and did not experience any significant problems. > > It may be worth remarking in the docs (sorry if I missed it) what facilities are used for the type registries that are presumably behind the scenes. From the reference section I think RTTI is required. Is this a hard limit or could Boost.TypeIndex be used? > > NB the reference section has a note “REVIEW THIS DESIGN DECISION” in it. > > Personally I would attach value to the fact that the author has been a great servant to Boost over the years (as have many others) so it is likely that this would be a well-maintained library. E.g. if algorithms were added to <algorithm> in the future, they would likely end up in <boost/poly_collection/algorithm.hpp> too. > > Regards, > Pete >

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[review][poly_collection] Review period EXTENDED until May 17th
by Ion Gaztañaga 11 May '17

11 May '17

Dear boosters, Some have requested a bit of time to extend the review period in order to have time to submit reviews or issue technical comments. With the approval of Review Wizards, the review of PolyCollection is extended until May 17th. Please feel free to submit review and comments. Best, Ion

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[poly_collection] Two remarks
by Dominique Devienne 10 May '17

10 May '17

Just as Pete Bartlett mentioned, I'm also a fan of Joaquín's Multi-Index, which I'm used in production for many years as well. My only complaint about his proposed Poly-Collection is the fact I can't leverage and thus benefit from the performance of it, in a multi-index scenario, but as Joaquín already answered a few months ago, that's off-topic and by design, I know :) Many of my BMIs have a by-type index, and the type-partitioned storage of those in contiguous memory for by-type scans would be (greatly?) beneficial. I'd be willing to give up some iterator guarantees BMI provides, as a node-based container, for intelligent contiguous storage of elements, without myself having to maintain by-value homogeneous containers with a manually maintained BMI of polymorphic pointers to those containers' elements. My second remark is about parallelism. I suspect the new poly_collection could be used for more efficient parallel (and/or concurrent) processing of elements, and would be interested in examples and even a ::parallel_for_each() algorithm that leverages the collection's internal storage. And perhaps even on the write side, rather than having to make the whole container thread-safe, but external mutexing for example, provide ways for a more granular thread-safety by type or segment perhaps. Again, probably off topic, but hardly something you can "add from the outside" I think, and why I mention it here and now. As merely a user of Boost, I don't feel qualified as a reviewer, beyond the two above remarks. Thanks, --DD

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[build] please review the long standing pull request
by Konstantin Ivlev 10 May '17

10 May '17

Hello, There's a 2 month old pull request https://github.com/boostorg/build/pull/169. Please review and let me know any feedback.

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[Thread] What is the meaning of BOOST_THREAD_USE_LIB?
by Frédéric Bron 09 May '17

09 May '17

Hi, I always use boost as static libraries. For a long time, I have been used to define macro BOOST_THREAD_USE_LIB on windows when cross-compiling from linux to windows with mingw. I have now made a new cross-compiler conformant with pthread (the previous one had only win32 api) but then boost does not build (with threadapi=posix). It seems that not defining BOOST_THREAD_USE_LIB helps. I do not remember why I used to define BOOST_THREAD_USE_LIB a long time ago and cannot find any help in the doc (http://www.boost.org/doc/libs/1_64_0/doc/html/thread/build.html) What is the meaning of BOOST_THREAD_USE_LIB? Frédéric

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gsoc17 and boost.ublas
by Rishabh Arora 09 May '17

09 May '17

Hi Everyone, My name is Rishabh Arora and I have been selected to work with the BoostC++ libraries on the the project, "dataframes in ublas" as a part of GSoC '17. It will be great if someone could provide me with suggestions on how to get started with it. Thank you in advance Best Regards, Rishabh Arora

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[GSOC'17] Project: Optimising Multiplications in uBLAS
by mohammad sharique 09 May '17

09 May '17

Hello Boost Community, My name is Mohd Sharique. I have been selected to work with Boost C++ Libraries under Google Summer of Code '17. My project is "Optimising Multiplications in uBLAS". It would be great if I could get some starting point for the same. Thank you, Your's sincerely, Mohd Sharique

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[integer] Please fix build/test errors..
by Rene Rivera 09 May '17

09 May '17

The Integer library is causing general CI failures: < https://travis-ci.org/boostorg/boost/jobs/230199520#L6396> Please rectify ASAP. -- -- Rene Rivera -- Grafik - Don't Assume Anything -- Robot Dreams - http://robot-dreams.net -- rrivera/acm.org (msn) - grafikrobot/aim,yahoo,skype,efnet,gmail

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[poly_collection] throws upon insertion
by Andrzej Krzemienski 09 May '17

09 May '17

Hi, I am looking at the documentation of poly_collection. I will not be able to thoroughly review and test the library. But judging from the documentation, the problem is worth solving, and the approach to solve it is sound. I have one question/observation though. I am trying to figure out how preventing an incorrect insert() works. In the docs ( http://rawgit.com/joaquintides/poly_collection/website/doc/html/poly_collec…) it says that it will sometimes throw if it cannot determine the most derived type. In the class reference, I get: ( http://rawgit.com/joaquintides/poly_collection/website/doc/html/poly_collec… ) ``` (1) c.insert(x) (2) c.insert(it,x) Effects: If the type of the subobject of t is not registered, then if this type is T and T is acceptable, does the registration, otherwise throws. If t is not a non-const rvalue expression and the type of its subobject is not CopyConstructible, throws. Inserts an element with a subobject move constructed or copy constructed from the subobject of t: (1) at the end of the corresponding segment; (2) just before the position indicated by it, if it points to the corresponding segment, or at the end of the segment otherwise. Returns: An iterator to the newly inserted element. Complexity: Amortized constant time plus linear in the distance from the insertion position to the end of the segment. ``` And maybe it is just me, but I cannot make the sense of it. First, it refers to 't' but in the signatures we have an 'x'. Next, the first sentence has two "if"s and one "otherwise" and I do not know which "if" the "otherwise" binds to. I read it as saying: if T is derived from the interface (like class `warrior`) but is not movable (which implies that T is not "acceptable"), then the program will compile fine but will later throw an exception. Is my interpretation correct? But if so, why not refuse to compile instead? Maybe it would be better tom make the prose longer in "Effects" clause, but to make it harder for misinterpretation. Regards, &rzej;

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[Boost.Test] access to boost::unit_test::framework::master_test_suite().{argc, argv} outside from BOOST_TEST
by Olaf Peter 08 May '17

08 May '17

Hello, my test program uses boost.test datasets. I've wrote a filesystem loader for the input and expected data. Now I run into the problem, that boost::unit_test::framework::master_test_suite().{argc, argv} is only setup inside the tests self. My loader isn't a test case ... I can check it by using a simple mock, like struct app_mock { app_mock(); int const argc; char** const argv; }; app_mock::app_mock() : argc(boost::unit_test::framework::master_test_suite().argc) , argv(boost::unit_test::framework::master_test_suite().argv) { } BOOST_AUTO_TEST_CASE( app_mocker ) { app_mock app; std::cout << "Count = " << app.argc << '\n'; for(int i = 0; i != app.argc; i++) std::cout << "Arg = " << app.argv[i] << '\n'; } $ my_test -- my_args Count = 2 path/to/exe my_args these works, but as mentioned: dataset_loader::dataset_loader(fs::path const& path) { app_mock app; std::cout << "ARGC = " << boost::unit_test::framework::master_test_suite().argc << '\n'; read_files(path); } is always zero. How can I read the argc/argv values? Thanks, Olaf

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