August 2017 - Boost - lists.preview.boost.org

Superproject 1.55.0 tags incorrect for libs/uuid?
by James E. King, III 29 Aug '17

29 Aug '17

Hello, Someone reported a discrepancy in boost trac that needs to be investigated by folks on the superproject team. What is claimed is that the superproject tag for boost-1.55 contains commit id 8c395a888c2d77bdc91e956ef24a07c0c87cdd24 for uuid, however this commit id does not exist. The tag id in the boost/uuid repository points to commit 98cf8322aef86e6398dbac7f9cd6bf766621d645. I would have opened up a github issue on the superproject to track this and resolve it, however the "issues" section is not activated for the superproject. https://svn.boost.org/trac10/ticket/13071 Instructions given to reproduce the issue are as follows: git clone https://github.com/boostorg/boost.git cd boost git submodule init libs/uuid git checkout boost-1.55.0 git submodule update libs/uuid and the last step will fail with: fatal: reference is not a tree: 8c395a888c2d77bdc91e956ef24a07c0c87cdd24 Unable to checkout '8c395a888c2d77bdc91e956ef24a07c0c87cdd24' in submodule path 'libs/uuid' Thanks, Jim

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Interest in thermodynamic properties of water and steam
by Belcourt, Kenneth 29 Aug '17

29 Aug '17

Hi, Would there be any interest in an implementation of the IAPWS-95 in Boost? Here’s the reference: The IAPWS Formulation 1995 for the Thermodynamic Properties of Ordinary Water Substance for General and Scientific Use. Authors: W. Wagner and A. Pruss J. Phys. Chem. Ref. Data, Vol. 31, No. 2, 2002, pages 387-535 For those with access to the paper, the code reproduces Table 6.6 (results agree to all published digits), as well as well significant parts of both Table 13.1 (vapor-liquid phase boundary properties as function of temperature) and Table 13.2 (properties of water in single-phase as function of temperature and density for pressures in range of 0.05 MPa to 1000 MPa). Also implemented are the full set of algorithms in Table 6.3, including pressure, enthalpy, entropy, sound speed, heat capacities. There’s also an algorithm for computing the thermal saturation properties (pressure, liquid and vapor densities), given the saturation temperature. At present the code has a required dependency on Boost.Units and is about 2k loc. If you're interested in this, feel free to reply or contact me directly. — Noel Belcourt [1] http://www.iapws.org

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Question/Remark to your include/boost/numeric/ublas/lu.hpp
by Ziehe, Dieter 29 Aug '17

29 Aug '17

Dear development community, first of all, thanks for your work, I use boost sometimes to ease from it in my development of math algorithm. Normally I try and check your code and documentation till it works (for example Edmonds karp, remez ...) But now I came to one point, which I don't understand and only workarounded it (although I'm a mathematician and the topic LU-Decomposition is easy). My Problem is lu.hpp:: lu_factorize and this part : (*) #if BOOST_UBLAS_TYPE_CHECK swap_rows (pm, cm); BOOST_UBLAS_CHECK (singular != 0 || detail::expression_type_check (prod (triangular_adaptor<matrix_type, unit_lower> (m), triangular_adaptor<matrix_type, upper> (m)), cm), internal_logic ()); #endif Despite the fact, that I can BOOST_UBLAS_TYPE_CHECK switch off (with BOOST_UBLAS_NDEBUG) I don't understand the sense of these lines. As far as I know, LU is in every case possible, either a matrix is singular or not. For example the ZERO-Matrix is also LU- decomposable (Solution ZERO-Matrix and Identity Matrix). And so, IMHO the lines are too strong for this situation. These lines lead in remez to an Exception : remez failed with exception: internal logic , but the remez algorithm is right (without BOOST_UBLAS_TYPE_CHECK) I got the correct results. Is it possible to weaken the lines (*) to a hint only (the return-value singular is also available for other user, who need regularity). Maybe I'm wrong. But if so, I'd like to know the argument, which lead to such strong reaction in the normal case of singular Matrix inside the LU-Algorithm ? I'm looking forward to hear from you. Many thanks. Dieter from Berlin

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[Intrusive]
by degski 28 Aug '17

28 Aug '17

I having trouble understanding the documentation of Boost.Intrusive. I'm referring to this section in particular: http://www.boost.org/doc/libs/1_65_0/doc/html/intrusive/intrusive_vs_nontru… "The main difference between intrusive containers and non-intrusive containers is that in C++ non-intrusive containers store *copies* of values passed by the user." This is confusing, as that might not be true in case of C++11 and up. Does (or rather, can) move-construction invalidate the use case for Intrusive containers? "On the other hand, an intrusive container does not store copies of passed objects, but it stores the objects themselves. The additional data needed to insert the object in the container must be provided by the object itself." But then in the example for slist, it seems from the example code that (a) pointer(s) to the original object are stored (and makes it look like the object), but that's not what I read from the quoted text. class MyClass{ MyClass *next; MyClass *previous; //Other members...}; int main(){ acme_intrusive_list<MyClass> list; MyClass myclass; list.push_back(myclass); //"myclass" object is stored in the list assert(&myclass == &list.front()); return 0;} I would like to ask for somebody to confirm I'm right, or explain to me in language (palatable to a thick user) what is actually stored (in terms of implementation). Thanks in advance, degski -- "*Ihre sogenannte Religion wirkt bloß wie ein Opiat reizend, betäubend, Schmerzen aus Schwäche stillend.*" - Novalis 1798

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[detail] boost/detail/utf8_codecvt_facet.hpp broken by recent change
by Beman Dawes 28 Aug '17

28 Aug '17

boost/detail/utf8_codecvt_facet.hpp fails to compile for STL's MinGW distro from https://nuwen.net/mingw.html The error message is: ..\..\../boost/detail/utf8_codecvt_facet.hpp:117:29: error: function 'boost::filesystem::detail::utf8_codecvt_facet::~utf8_codecvt_facet()' definition is marked dllimport virtual BOOST_UTF8_DECL ~utf8_codecvt_facet(){} The problem (on develop) is caused by Robert Ramey's Aug 13 commit 73c12230c31a851c15ecb9a649468425ebd92f8e "adjustment to avoid linking problem: vtable not found found for ~utf8_codecvt_facet.hpp" which added "BOOST_UTF8_DECL" to line 117. This is breaking my local filesystem tests for GCC/MinGW. If the change is reverted, the tests start passing again. Robert, could you please revert the change? I can also to it, but thought you needed to be alerted first so you can revisit whatever you were trying to fix. Thanks, --Beman

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[release] 1.65.1 closing on Thursday
by Daniel James 28 Aug '17

28 Aug '17

Hi, I've added a schedule for 1.65.1 to the calendar: http://www.boost.org/development/ I think it should be possible to get the changes ready in the next two days, although the schedule is a little flexible. I might also release a little early if everything goes smoothly. We don't want to spend too much time on this. Daniel

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[iterator] What documentation is actual?
by Andrey Semashev 27 Aug '17

27 Aug '17

Hi, While moving next_prior.hpp to Boost.Iterator I've noticed that thete are basically two versions of the documentation in Boost.Iterator: rst and QuickBook. It seems like QuickBook is in progress of being written and is largely a conversion of rst, but is incomplete in some places. I'd like to ask what's the plan about it? Since I don't know rst I converted the original documentation of next_prior.hpp to QuickBook and added it to the current QuickBook docs. I also converted advance() and distance() docs to QuickBook and fixed a few problems in the docs so that it is at least browsable and readable. If we have no plans to switch to QuickBook then I suppose it is better to remove them to avoid confusion. Also, someone has to convert next_prior.hpp docs to rst (I don't know how to do this).

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Purchasing Travis Resources for boostorg (was Re: [1.65.0] Point release?)
by Tom Kent 27 Aug '17

27 Aug '17

On Sat, Aug 26, 2017 at 1:16 PM, Daniel James via Boost < boost(a)lists.boost.org> wrote: > On 26 August 2017 at 18:02, Peter Dimov via Boost <boost(a)lists.boost.org> > wrote: > > Daniel James wrote: > > > But we don't rely that much on the testers nowadays, so this would be > less > > of an issue. > > I do. The turnaround on Travis is pretty terrible at the moment, and > that's going to get worse as more modules use it. While I'm a big fan of Boost's test system, and believe that it is an awesome resource that can't be replicated on the common CI services (lots of platforms and compiler versions/configs!), I also think that good per-commit CI on a service like travis is hugely important. Maybe someone should present a proposal to the steering committee to start paying for boostorg's account to have additional build resources? Tom

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[1.65.0] Point release?
by Daniel James 27 Aug '17

27 Aug '17

Hello all, What do you think about having a point release? I tried asking the other release managers but didn't get any reply. Some are away, and I don't known when they will be available again. I think we have to decide soon, as it's holding up development. This would deal with the issues in thread, context, fiber, and possibly others. I've added patches to the release notes: http://www.boost.org/users/history/version_1_65_0.html A point release should take a week or two, perhaps more if we include other changes. thanks, Daniel

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[Boost-build] Broken installation with `./b2 --prefix=/tmp/boost --with-stacktrace install`
by Antony Polukhin 26 Aug '17

26 Aug '17

Hi, People complain about the broken installation. Command `./b2 --prefix=/tmp/boost --with-stacktrace install` does not copy the boost/stacktrace/detail/push_options.pp and boost/stacktrace/detail/pop_options.pp files into the destination folder. See https://github.com/boostorg/stacktrace/issues/29 How this could be fixed? Is that a b2 issue? -- Best regards, Antony Polukhin

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