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[property_tree] Failure with Boost 1.56
by beet 10 Oct '14

10 Oct '14

Dear all, with the release of Boost 1.56, on Ubuntu 14.04 (g++ 4.8.2, 64 bit), code like the following suddenly fails to compile: pt::xml_writer_settings<char> settings('\t', 1); pt::write_xml(someFileName, ptr_out, std::locale(), settings); "pt" is obviously an alias for boost::property_tree. The error message I'm getting is /opt/boost156/include/boost/property_tree/detail/xml_parser_writer_settings.hpp:38:35: error: 'char' is not a class, struct, or union type typedef typename Str:… [View More]

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[Boost.Polygon] Bug in polygon_set_data, or are my expectations wrong?
by Patrick J. LoPresti 09 Oct '14

09 Oct '14

I have just submitted a bug report: https://svn.boost.org/trac/boost/ticket/10642 ...but I am wondering if the bug is in my understanding rather than in Boost.Polygon. The test case is very simple, so I am appending it to this message. My question is, should I expect polygon_set_data<int> to scramble such a simple figure? It almost looks like some (but not all) of the coordinates are being snapped to multiples of 2. Or something. Note that doubling all of the coordinates avoids the … [View More]

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[polygon] Incorrect output from get_trapezoids(..., HORIZONTAL)
by Patrick J. LoPresti 08 Oct '14

08 Oct '14

I apologize for sending this to the mailing list, but when I tried to file a bug report via Trac, it said "Trac thinks your submission might be Spam. To prove otherwise please provide a response to the following"... And then there was no "following". Please let me know if there is a better forum to report this sort of issue. I am using Boost 1.56. The following program uses boost::polygon to slice up a figure (with a "hole" cut out of it) into horizontal trapezoids. The output I get is: … [View More]Output: polygon (4 3) (4 0) (0 0) (0 3) (4 3) ...which is clearly wrong. I am pretty sure my code is correct, because if I replace bg::HORIZONTAL with bg::VERTICAL, I get the correct output of a bunch of vertical trapezoids. For my application, I really want horizontal traps. I suppose I can just swap x and y on input and output... But this seemed worth reporting. Thanks. - Pat #include <boost/polygon/polygon.hpp> #include <iostream> namespace bp = boost::polygon; typedef bp::polygon_set_data<int> PolygonSet; typedef bp::polygon_data<PolygonSet::coordinate_type> Polygon; typedef bp::polygon_traits<Polygon>::point_type Point; std::ostream & operator<<(std::ostream &os, const Point &pt) { return os << "(" << bp::x(pt) << " " << bp::y(pt) << ")"; } std::ostream & operator<<(std::ostream &os, const Polygon &poly) { os << "polygon "; for (Polygon::iterator_type p = poly.begin() ; p != poly.end() ; ++p) os << " " << *p; return os; } std::ostream & operator<<(std::ostream &os, const PolygonSet &ps) { std::vector<Polygon> temp; ps.get(temp); os << "polygonset "; for (std::vector<Polygon>::const_iterator p = temp.begin() ; p != temp.end() ; ++p) os << " " << *p; return os; } int main(int argc, char *argv[]) { const Point points[] = { Point(2,0), Point(4,0), Point(4,3), Point(0,3), Point(0,0), Point(2,0), Point(2,1), Point(1,1), Point(1,2), Point(3,2), Point(3,1), Point(2,1) }; Polygon poly; bp::set_points(poly, &points[0], &points[sizeof(points)/sizeof(points[0])]); std::cout << "Input: " << poly << "\n"; PolygonSet ps; ps.insert(poly); std::cout << "ps = " << ps << "\n"; std::vector<Polygon> traps; // Note: bp::VERTICAL works fine bp::get_trapezoids(traps, ps, bp::HORIZONTAL); std::cout << "Output:\n"; for (std::vector<Polygon>::const_iterator p = traps.begin() ; p != traps.end() ; ++p) std::cout << *p << "\n"; } [View Less]

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program_options: Make PO not eat argc
by Florian Lindner 08 Oct '14

08 Oct '14

Hello, I have a couple of libraries (MPI, petsc) that also consume my applications argc and argv, which is parsed with boost::program_options before. po seems to eat up argv, i.e. removes all items that it handles. Can I disable that behavior somehow so that po does not touch argc/argv. Or do I need to recreate it, e.g. using collect_unrecognized? Thanks, Florian

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program_options: How to best model two/three pos args
by Florian Lindner 08 Oct '14

08 Oct '14

Hello, my application has positional arguments like that: Run tests : ./app test ConfigurationName PathToSrc Run server : ./app server ParticipantName ConfigurationName Print XML reference: ./app xml Linewidth It has three (if first in [test, server]) or two (if first in [xml]) positional arguments. How to model and test this best using boost? I could add three options and declare them as positional arguments, named like "first", "second", "third". I could also use … [View More]

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MSM to diagram
by Robert Bielik 08 Oct '14

08 Oct '14

Hi all, I want to use MSM in an application, however, for design documentation purposes I'd like to be able to express the state machine in a diagram. And preferably going the route from C++ code -> graphical diagram (i.e. not from UML -> C++ code). Has anyone looked at that, or know of resources on how to accomplish this ? TIA /Robert

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[general] Advice from Bjarne Stroustrup
by legalize+jeeves＠mail.xmission.com 06 Oct '14

06 Oct '14

[Please do not mail me a copy of your followup] At the end of each chapter in "The C++ Programming Language", 4th edition, Bjarne Stroustrup has a list of advice. I found the advice very helpful and decided that the advice should be online somewhere. Initially I put this together as a PPT presentation, but oh my lord, it was too long. Instead, I made a page in my user space on the cppreference.com wiki: <http://en.cppreference.com/w/User:Legalize/Advice_from_Bjarne_Stroustrup> This … [View More]

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NT² eand Boost.SIMD release 3.1
by Joel FALCOU 06 Oct '14

06 Oct '14

NT2 is a Matlab inspired, high-level API for scientific computation in C++. Boost.SIMD is a candidate library for inclusion in Boost dealing with the portable encpsulation of SIMD instructions sets. This following releases updates NT2 and Boost.SIMD libraries to version 3.1 This new release of NT2 and Boost.SIMD focused on fixing performance issues and add some new support for architecture and parallel algorithms. The main new features include: - Linear Algebra functions can now use GPGPU … [View More]

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[bimap] Look ups on the vector_of collection type
by Arindam Mukherjee 05 Oct '14

05 Oct '14

Would it make sense to define a bimap like this: boost::bimap< boost::bimaps::set_of<std::string>, boost::bimaps::vector_of<std::string>> mymap; And then make the right view (vector_of) more amenable to lookups by performing a sort followed by a binary search on it? Thanks.

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Flat multi set operation costs
by Paolo Bolzoni 03 Oct '14

03 Oct '14

Dear list, In a project of mine I am using a sorted vector as a multimap. The point was that insert, delete and retrieval operations arrived in batches (lots of inserts, lots of retrieval, lots of deletes...) so I essentially saved time sorting the vector when a new kind of operation arrived. I recently noticed boost has the flat multiset implementation, so I was wondering do it follows the same idea? If it does I would be nice to kick-out some code and use the library for ease of maintenance.… [View More]

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