April 2016 - Boost-users - lists.boost.org

Re: [Boost-users] [boost.multiprecision] export_bits throws on a negative number
by Tassilo Glander 28 Apr '16

28 Apr '16

Hi John, thanks for stepping in. I would expect that the export just exports the memory representation of the number - maybe with flipped order via msv_first parameter. Especially, something exported via export_bits and than imported via import_bits should be the same, at least on the same platform. That said, I actually was just looking for a way to implement a hash function and thought it was straightforward to use chunks of char. But I could also compute the hash on the str() output. Tassilo

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[boost.multiprecision] export_bits throws on a negative cpp_int number
by Tassilo Glander 28 Apr '16

28 Apr '16

Dear List, When calling export_bits on a negative boost::multiprecision number based on cpp_int, an exception is thrown from the internal method msb ("testing individual bits in negative values is not supported"). boost::multiprecision::checked_int128_t i (-1); // use negative number std::vector<unsigned char> v; export_bits(i, std::back_inserter(v), 8); // throws How can I extract the content of a boost::multiprecision number? Boost documentation says, export_bits is designed to be used for data exchange, so in my understanding it would be a major flaw, if it cannot export supported values. I learnt that a workaround might be to directly access the backend's limbs, but this way I am accessing internals that may change. http://www.boost.org/doc/libs/master/libs/multiprecision/doc/html/boost_mul… I also asked this on http://stackoverflow.com/questions/36890928/boostmultiprecisionexport-bits-…, but this list is probably the better place. Thanks, Tassilo

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[PBGL] compilation of example/dijkstra_shortest_paths.cpp failed
by Eisuke Kawashima 27 Apr '16

27 Apr '16

Dear all, I tried to compile http://www.boost.org/doc/libs/1_60_0/libs/graph_parallel/example/dijkstra_sh ortest_paths.cpp, an example code of Parallel Boost Graph, resulting in faulure; example/breadth_first_search.cpp has no problem. My environment is: * GCC 4.9.2 * OpenMPI 1.10.2 * boost 1.60.0 * OS: Debian jessie The error, related to template, is long; the summary is: $ mpicxx -std=c++11 -lboost_mpi -lboost_serialization -lboost_system - lboost_graph_parallel dijkstra_shortest_paths.cpp In file included from boost/graph/dijkstra_shortest_paths.hpp:25:0, from dijkstra_shortest_paths.cpp:19: boost/pending/relaxed_heap.hpp: In instantiation of ‘bool boost::relaxed_heap... boost/graph/distributed/crauser_et_al_shortest_paths.hpp:377:54: required from ... boost/graph/distributed/detail/remote_update_set.hpp:148:7: required from ... boost/graph/distributed/crauser_et_al_shortest_paths.hpp:264:37: required from ... boost/graph/breadth_first_search.hpp:76:7: required from ... boost/graph/breadth_first_search.hpp:124:69: required from ... boost/graph/breadth_first_search.hpp:135:64: [ skipping 4 instantiation contexts, use -ftemplate-backtrace-limit=0 to disable ] boost/graph/distributed/dijkstra_shortest_paths.hpp:146:50: required from ... boost/graph/distributed/dijkstra_shortest_paths.hpp:200:45: required from ... boost/graph/dijkstra_shortest_paths.hpp:573:16: required from ... boost/graph/dijkstra_shortest_paths.hpp:595:35: required from ... boost/graph/dijkstra_shortest_paths.hpp:614:14: required from ... dijkstra_shortest_paths.cpp:74:64: required from here boost/pending/relaxed_heap.hpp:194:70: error: cannot convert ‘const value_type {aka const boost::optional<boost::detail::parallel::global_descriptor<long unsigned int> >}’ to ‘bool’ in return bool contains(const value_type& x) const { return groups[get(id, x)]; } ^ "-ftemplate-backtrace-limit=0" flag did not work. How to fix this? -- Eisuke Kawashima

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[boost-users][boost graph] edge_descriptor problem when copy from original graph
by Emerson Xu 26 Apr '16

26 Apr '16

Hi all, I have a boost graph copy problem that has been nagging me for a long time. My question is, is there anyway that I can construct a graph once, and reuse it multiple times, each time I may mutate the graph a bit. I have a class, which creates a boost graph with bundled vertex and edge properties (my own properties, vertices are routers in a network, while edges are logical links between routers). When creating the graph, some helper unordered maps are also created, like mapping from an edge_descriptor to a logical link name, from a router name to a vertex_descriptor, etc. Now there are multiple clients calling some method in the class. Current strategy is to construct a new boost graph instance for every client, and run the service on each graph instance. Now I want to improve the performance by avoiding constructing the graph for every client ( >100 clients are calling it simultaneously). So I am thinking that we can initialize only one base graph, and make it a copy for every client. Then the problem comes, since in the method the client needs use those helper unordered maps, but the data inside the maps are from that original base graph. Even if I use a copy constructor(deep copy) for each graph copy, some graph data is still inconsistent, like the edge_descriptor, for example, I can't use the hashmap with edge_descriptor as key, because this edge_descriptor only points to the memory address of base graph. Best, Emerson

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error when copying blocks into a dynamic_bitset
by Diab Jerius 26 Apr '16

26 Apr '16

Hi, I'm trying to initialize a dynamic_bitset<unsigned char> from a vector of blocks. Here's the code: #include <cstdlib> #include <vector> #include <boost/dynamic_bitset.hpp> typedef boost::dynamic_bitset<unsigned char> BitSet; typedef std::vector<BitSet::block_type> Block; int main(int argc, char* argv[]) { int nbits = atoi( argv[1] ); BitSet bits( nbits ); Block buffer; buffer.resize( bits.num_blocks(), 0xff ); boost::from_block_range(buffer.begin(),buffer.end(), bits ); return 0; } If the bitset size isn't a multiple of sizeof(unsigned char) (here 8) , ~dynamic_bitset() throws an exception. For example: % ./a.out 1 a.out: boost-1.60.0/include/boost/dynamic_bitset/dynamic_bitset.hpp:633: boost::dynamic_bitset<Block, Allocator>::~dynamic_bitset() [with Block = unsigned char; Allocator = std::allocator<unsigned char>]: Assertion `m_check_invariants()' failed. Aborted % ./a.out 8 % ./a.out 15 a.out: boost-1.60.0/boost/dynamic_bitset/dynamic_bitset.hpp:633: boost::dynamic_bitset<Block, Allocator>::~dynamic_bitset() [with Block = unsigned char; Allocator = std::allocator<unsigned char>]: Assertion `m_check_invariants()' failed. Aborted % ./a.out 16 % I see this with 1.59 & 1.60 using either g++ 4.7.2 or Apple LLVM version 6.0 (clang-600.0.57) (based on LLVM 3.5svn) I believe that I'm following the rules for the buffer type and size. Is there something I'm missing? Thanks! Diab

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Compiler errors using boost/program_options with Boost v 1.53 and v 1.59
by Christine Peters 26 Apr '16

26 Apr '16

Dear all, I had to reinstall my boost version as the cluster environment I'm working on has switched from Scientific Linux 6 to CentOS 7. When I'm now compiling my code including the header "#include <boost/program_options>", I will receive the following error message: In file included from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/mpl/aux_/arithmetic_op.hpp:34:0, from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/mpl/times.hpp:19, from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/mpl/multiplies.hpp:17, from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/numeric/conversion/detail/is_subranged.hpp:17, from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/numeric/conversion/detail/conversion_traits.hpp:21, from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/numeric/conversion/conversion_traits.hpp:13, from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/numeric/conversion/converter.hpp:13, from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/numeric/conversion/cast.hpp:33, from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/lexical_cast/detail/converter_numeric.hpp:37, from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/lexical_cast/try_lexical_convert.hpp:34, from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/lexical_cast.hpp:32, from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/program_options/value_semantic.hpp:14, from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/program_options/options_description.hpp:13, from /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/program_options.hpp:15, from /home/cp652127/EclipseWorkspace/AMD-Geant4.10/amd/externals/g4sipm/sample/include/ParticleSourceMessenger.hh:24, from /home/cp652127/EclipseWorkspace/AMD-Geant4.10/amd/externals/g4sipm/sample/include/AsciiPersistencyHandler.hh:20, from /home/cp652127/EclipseWorkspace/AMD-Geant4.10/amd/externals/g4sipm/sample/include/RunAction.hh:16, from /home/cp652127/EclipseWorkspace/AMD-Geant4.10/amd/externals/g4sipm/sample/src/RunAction.cc:9: /home/phys3aauger/tine/ApeInstalled/External/boost/1_59_0/include/boost/mpl/aux_/include_preprocessed.hpp:37:90: fatal error: boost/mpl/aux_/preprocessed/gcc/ostimes.hpp: No such file or directory # include BOOST_PP_STRINGIZE(boost/mpl/aux_/preprocessed/AUX778076_PREPROCESSED_HEADER) ^ compilation terminated. This fatal error occurs with my own boost installation (version 1.59.0) but also with the system default boost (version 1.53.0). It worked properly on Scientific Linux 6. Now, I'm using gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-4), CPU codename Intel Nehalem EX, LINUX, CENTOS 7.2 environment. I would be very glad if someone could help me. It seems that somehow the AUX778076 parameter defined in "boost/1_59_0/include/boost/mpl/times.hpp" is converted to ostimes during the compilation: I've changed, just for testing reasons!, in file "/boost/1_59_0/include/boost/mpl/times.hpp" the line "#define AUX778076_OP_NAME times" to "#define AUX778076_OP_NAME timestest" and then boost is searching for the correct header "timestest.hpp" but in the case of "#define AUX778076_OP_NAME times" it is searching for "ostimes.hpp" instead of "times.hpp". Thanks in advance for your help! Cheers, Christine

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Typo in BGL Subgraph
by Eisuke Kawashima 23 Apr '16

23 Apr '16

Dear all, I submitted the following to boost-docs but have received no response, so also submitting to boost-users. The last part of Boost Graph Library: Subgraph <http://www.boost.org/doc/libs/release/libs/graph/doc/subgraph.html> (since Boost 1.40) > > struct my_vertex { ... }; > typedef property<vertex_index_t, std::size_t, vertex_prop> vertex_prop; > struct my_edge { ... }; > typedef property<edge_index_t, std::size_t, vertex_prop> edge_prop; should be > > struct my_vertex { ... }; > typedef property<vertex_index_t, std::size_t, my_vertex> vertex_prop; > struct my_edge { ... }; > typedef property<edge_index_t, std::size_t, my_edge> edge_prop; Additionally I want you to note how to modify GraphProperties of boost::subgraph (or whether it is not implemented). Regards, -- Eisuke Kawashima email: e.kawaschima(a)gmail.com

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[interprocess] posix_recursive_mutex constructor never called, fails to init mutex
by Adrian Cheater 23 Apr '16

23 Apr '16

This was submitted as a bug (https://svn.boost.org/trac/boost/ticket/12150) but I don't know that this is actually a boost bug, possibly a OSX or clang issue, or maybe I'm just doing something silly, so I'm hoping someone here can shed some light on the issue. I'm trying to use boost's shared memory system to get data from another application, but while it works fine on Ubuntu 15.10 with boost 1.58 and 1.60 on gcc, clang-3.6 and clang-3.7, it throws an exception when it attempts to acquire the mutex lock on OSX because the mutex has not been initialized. Placing a breakpoint in the constructor for the recursive_lock never gets hit, and I'm not sure why. Hopefully someone with more OSX experience can help me sort this out. Thanks very much for your time.

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Compiler does not give error for missing serialize function
by Elizabeta 22 Apr '16

22 Apr '16

Hi I have the following code : class MyClass { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive &ar, const unsigned int version) {} }; class MyClass2 : public MyClass {}; MyClass2* ss = new MyClass2; std::ofstream ofs("C:\\test.xml"); boost::archive::xml_oarchive oa(ofs); oa & boost::serialization::make_nvp("test",ss); I am serializing trough the derived class pointer. The derived class doesnot have serialize function. The Base have. And I was expecting compiler to give me error that MyClass2 doesnot have serialize function. But this code compiles without errors. I am using vs2010. -- View this message in context: http://boost.2283326.n4.nabble.com/Compiler-does-not-give-error-for-missing… Sent from the Boost - Users mailing list archive at Nabble.com.

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[gsoc16] Summer of Code 2016 shall proceed after all
by Niall Douglas 22 Apr '16

22 Apr '16

Dear Boost, We are very glad to announce that non-Google funding has been found to continue the Summer of Code for the following veteran student projects in Summer 2016: A. Boost Document, mentored by Antony Polukhin. Veteran student: Anurag Ghosh https://anuragxel.github.io/boost-document/ B. Boost.Compute, mentored by Kyle Lutz. Veteran student: Jakub Szuppe https://boostorg.github.io/compute/ C. Boost.Http, mentored by Bjorn Reese. Veteran student: Vinícius dos Santos Oliveira https://boostgsoc14.github.io/boost.http/ All three of these projects shall see a Summer of Code as if it were Google Summer of Code following the same timeline, mentor and student stipends, and progress acceptance criteria. Our thanks to the students and mentors for being so patient during the organisation of this funding. This all happened very quickly and much faster than Boost org processes normally happen - it would not have been possible without the efforts of Jon Kalb and Bryce Adelstein Lelbach, the latter of whom wrote up a great funding request worth reading at https://goo.gl/7v3VMK. Thanks are also due to the Boost Steering Committee for moving so quickly to vote on this, and to Boris Schäling for finding sponsorship for this effort. And finally congratulations to the veteran students! Niall and Bryce --- Boost C++ Libraries Google Summer of Code 2016 admin https://svn.boost.org/trac/boost/wiki/SoC2016

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