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Installing multiple versions of Boost libraries on Linux: Ubuntu & Debian.
by Stephen Gray 05 Mar '19

05 Mar '19

Please could someone advise how to install multiple releases of the Boost libraries on a Linux (Ubuntu & Debian) system and set the system paths to permit switching between them; so that a compiler refers to the desired version and the relevant runtime components are available to an application; e.g. the .so file for boost serialization. Thanks.

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Spatial search with boost r tree
by Bozo Vazic 01 Mar '19

01 Mar '19

Hi all, I'm trying to create a boost r tree with packing algorithm that will store 2D or 3D geometric points. This will be applied in side my peridynamic software for what we call "family search". Family search is basically a simple spatial search where each point of the peridynamic mesh (cloud of geometric points) needs to find all points inside it's horizon (horizon is for 2D a circle with a specific radius and for 3D it's a sphere with a specific radius). What I've found so far were examples for distance search using a random point (not the point that is a r-tree member). I did a distance and index check using bg::index::satisfies by passing a method that checks if the index is different and is distance smaller than radius. Also I use within(box) to constrain my search, but I'm not sure that is the correct way to use r tree spatial search for the point that is a member of the same r tree. Because as far as I understand the point in the r-tree knows has the information of boxes in which it is contained, so wouldn't there be a way to query the tree member using using only the horizon value? The reason why I'm asking this question is because I need to define most optimal spatial search so that query times don't take to long. This is important as I can have several million points that need to be constantly queried. Thnx in advance for all the help. Best Regads Bozo Here is my code for 2D search of only one point #include "stdafx.h" #include <boost/function_output_iterator.hpp> #include <boost/geometry/index/rtree.hpp> #include <boost/geometry.hpp> #include <boost/geometry/geometries/point.hpp> #include <boost/geometry/geometries/box.hpp> #include <vector> #include <iostream> namespace bg = boost::geometry; namespace bgi = bg::index; typedef bg::model::point <double, 2, bg::cs::cartesian> point; typedef std::pair<point, std::size_t> pointI; typedef bg::model::box<point> box; typedef std::pair<point, unsigned> value; bool CheckIndexAndDist(pointI i, pointI j, size_t dist); std::vector<uint64_t> res; struct StoreDataCallback { template <typename Value> void operator()(Value const& v) { res.push_back(v.second); } }; int _tmain(int argc, _TCHAR* argv[]) { std::vector<point> contourCenters; // has some value std::vector<pointI> cloud; double length = 2000; double width = 2000; double dX = length/1000.0; double horizon = 3.015*dX; for(int i = 0; i < length; i++) { for(int j = 0; j < width; j++) { point p; p.set<0>((-1.0 * length / 2.0) + dX + j * dX); p.set<1>((-1.0 * width / 2.0) + dX + i * dX); contourCenters.push_back(p); } } size_t id_gen = 0; std::transform( contourCenters.begin(), contourCenters.end(), back_inserter(cloud), [&](point const& p) { return std::make_pair(p, id_gen++); } ); bgi::rtree<pointI, bgi::quadratic<16> > rtree(cloud); // spatial search box query_box(point(cloud[10].first.get<0>() - 3.2*dX, cloud[10].first.get<1>() - 3.2*dX),point(cloud[10].first.get<0>() + 3.2*dX, cloud[10].first.get<1>() + 3.2*dX)); StoreDataCallback callback; rtree.query( bgi::within(query_box) && bgi::satisfies([&](value const& v) {return CheckIndexAndDist(v, cloud[10],3.015*dX);}), boost::make_function_output_iterator(callback)); return 0; } bool CheckIndexAndDist(pointI i, pointI j, size_t dist) { if( i.second != j.second && (bg::distance(i.first, j.first) < dist)) return true; else return false; }

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Boost archive import error.
by Stephen Gray 01 Mar '19

01 Mar '19

Dear boost-users, On Debian 8 I've compiled a Python extension written in c++ using pip install against Boost_1_66_0. My source code includes: #include "boost/archive/text_iarchive.hpp" #include "boost/archive/text_oarchive.hpp" #include "boost/serialization/map.hpp" #include "boost/serialization/deque.hpp" At runtime I receive the error: ImportError: /home/stephen/envs/pyclonestream/lib/python3.4/site-packages/pyclonestream.cpython-34m.so: undefined symbol: _ZN5boost7archive18text_iarchive_implINS0_13text_iarchiveEE13load_overrideERNS0_15class_name_typeEi I don't know what's wrong here. Please, any suggestions to fix the issue?

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[Concept] Understanding Boost Concept library
by Robert Jones 28 Feb '19

28 Feb '19

This is a small excerpt from the Boost Concepts library, there's various rather unusual techniques employed in it, with preprocessor tricks and various compiler specific tweeks, but this one has defeated me! What is the purpose of "*********** Model:: ***********" ? Maybe it's just to generate a distinctive diagnostic, but it's very sensitive to exact numbers of asterisks! In general what's going on here is the compiler is checking that the destructor of the Model (which is a concept instantiated with a particular type), can be instantiated, but without ever running the destructor or creating an instance of the Model. struct failed {}; template <class Model> struct requirement<failed ************ Model::************> { static void failed() { ((Model*)0)->~Model(); } }; Any insight appreciated. Kind Regards Rob.

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Ambiguous symbols possibly caused by Boost 1.69.0
by tim＠raisedbar.net 28 Feb '19

28 Feb '19

Hi, I'm getting several instances of the following kind of error when I build my code, which does not use boost::thread, etc., as I use the STD versions: 1>c:\program files (x86)\microsoft visual studio\2017\community\vc\tools\msvc\14.16.27023\include\condition_variable(1 24): error C2872: 'xtime': ambiguous symbol 1>c:\program files (x86)\microsoft visual studio\2017\community\vc\tools\msvc\14.16.27023\include\thr\xtimec.h(18): note: could be 'xtime' 1>c:\program files\boost\boost\thread\lock_types.hpp(31): note: or 'boost::xtime' My research turned up: https://svn.boost.org/trac10/ticket/11477?cversion=0&cnum_hist=10 So I added the following value for Windows 10 to my preprocessor: _WIN32_WINNT=0x0601; Unfortunately, this makes no difference. Can anybody advise me of a way forward, please? Best wishes. Tim Burgess Raised Bar Ltd. E: <mailto:tim@raisedbar.net> tim(a)raisedbar.net M: +44 (0)7989 486976

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hi i am a beginner user, there are some problem when using the library, can anyone help me with that ? plz
by ching han 25 Feb '19

25 Feb '19

i am trying to use the boost polygon function for example boost::geometry::read_wkt("multipolygon(((0 0 , 3 0 , 3 2 , 0 2)))", q); however i want to use the changing input such as "multipolygon(((A B, 0 2, 0 0, 4 0, 4 0)))" and A, B are the parameters defined by my previous array, but it ends up with showing the bad lexical cast since the parameters A and B can not be used or read if there is any solution that i can use the changing parameters as my polygon input, i kept searching for the answer but still can not find it can anyone plz help me, and i will be so grateful with that. thanks again!

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[release] 1.70.0 closed for major changes
by Marshall Clow 23 Feb '19

23 Feb '19

The master branch is now closed for new libraries and breaking changes, and will be closing for the beta in one week. Also, if you're ready, you can also add your libraries' changes to the release notes at: < https://github.com/boostorg/website/blob/master/feed/history/boost_1_69_0.q… > After editing the release notes, you should get a form to create a pull request, remember to submit it, otherwise I won't see your change. As always, the calendar for the release cycle is available at: https://www.boost.org/development/ Thanks, -- The Boost Release Team

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Re: [Boost-users] [boost.test] Colors
by Raffi Enficiaud 23 Feb '19

23 Feb '19

On 21.02.19 17:22, Udo Steinbach via Boost-users wrote: > Am 2019-02-20 um 22:38 schrieb Raffi Enficiaud via Boost-users: >> and this was fixed in 1.69 > > I have read it, but was so far been too lazy to compile it. > I think that colors may help with many lines of output, and only then. But > the default output of boost::test should be OK, one line. Everything else > needs attention, also no colors needed. You can set an environment variable globally if you want to avoid the default behaviour. See https://www.boost.org/doc/libs/1_69_0/libs/test/doc/html/boost_test/utf_ref… The variable BOOST_TEST_COLOR_OUTPUT is there for your need. > If you want color, you have to handle colors complete, not only 'red here, > green that'. Maybe console setup or unsuitable combinations or color > blindness (system in high contrast mode) or remote console or whatever that > you have to take into account. Right, so your problem is rather the color scheme of Boost.Test that is not playing well with your color scheme. It is true that I did not adjusted the background and I made the hypothesis of the default one. > Because color is not needed for test AND handling colors is not easy, > default should be colorless mode. I respectfully disagree with this statement. I personally like having color outputs, and combining this with log levels let me parse a big amount of information/logs significantly faster. > That are my first two general thoughts. https://en.wikipedia.org/wiki/De_gustibus_non_est_disputandum > >> open an issue next time on GitHub > > I try to avoid registration on free services. > I am fine with that. I still consult this list, although in a less regular manner. If the variable BOOST_TEST_COLOR_OUTPUT is good enough for you, or if you want an improvement, let me know. Best, Raffi

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Re: [Boost-users] [boost.test] Colors
by Mateusz Loskot 21 Feb '19

21 Feb '19

On Thu, 21 Feb 2019 at 17:22, Udo Steinbach via Boost-users <boost-users(a)lists.boost.org> wrote: > Am 2019-02-20 um 22:38 schrieb Raffi Enficiaud via Boost-users: > > > open an issue next time on GitHub > > I try to avoid registration on free services. FYI, GitHub also offers paid account. Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

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Boost Test thread safety
by Dan Field 21 Feb '19

21 Feb '19

Hi folks: I'm trying to identify whether or not the boost Test library is thread safe in the sense that multiple threads can simultaneously interact with the library's various macros and API. I'm more interested in a single test being multi-threaded than being able to run multiple test cases simultaneously. In early documentation of the Test library (version 1.58.0 and before) , there's a section in the introduction called "Open issues" that indicates that the library is not thread-safe. However, the documentation after 1.58.0 was substantially re-written, and I don't see any discussion regarding thread safety at all. The question remains. is the Test library thread-safe or not? If there is a definitive statement regarding this issue, please let me know. Thanks in advance!

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