May 2012 - Boost-users - lists.preview.boost.org

[interprocess] Determine size of managed_shared_memory
by Kai Benndorf 12 Oct '19

12 Oct '19

Hi all, I want to create a managed_shared_memory in exactly the size I needed. Therefore I do something like this: size = sizeof( common_managed_shared_memory ); size += sizeof( MyClassInSharedMem ); managed_shared_memory segment(create_only, "name", size ); MyClassInSharedMem allocates itself some memory by segment->allocate(). I added this also to the size, but get a boost::interprocess::bad_alloc exception on allocating this additional memory. Are there some magic bytes I forgot to add? Many thanks in advance Kai

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[statechart] Passing parameters from event to State Local Storage
by Christophe Bourez 16 Nov '16

16 Nov '16

I need to maintain a parameter into the state local storage. This parameter is initially contained in the event that causes the transition to the target state. I give hereafter a small illustrative example. typename sc = boost::statechart; class EvTest : public sc::event<EvTest> { public: EvTest(std::size_t val) : value(val) {} std::size_t getValue() const { return this->value; } private: std::size_t value; }; class MyStateMachine; class StSource; class StTarget; class StSource : public sc::simple_state<StSource, MyStateMachine> { public: typedef sc::custom_reaction<EvTest> reactions; sc::result react(const EvTest &event) { // How to pass event.getValue() to the target state ? transit<StTarget>(); } }; class StTarget : public sc::simple_state<StTarget, MyStateMachine> { public: StTarget(std::size_t val) : val(value) {} private: std::size_t value; }; Thanks, Christophe

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Statechart serialization
by mbrodeur65 04 Mar '15

04 Mar '15

Hi, I'm looking for a solution to serialize boost::statechart objects. I'm aware that this feature is on the statechart library todo list but was wondering if there are any workaround to achieve this with the latest boost release (1.34) ? thanks for your help ! mbrodeur65 -- View this message in context: http://www.nabble.com/Statechart-serialization-tf4131326.html#a11749139 Sent from the Boost - Users mailing list archive at Nabble.com.

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[Thread] Read-write locks
by lfrfly＠icqmail.com 18 Sep '14

18 Sep '14

I'm trying to create a standard read/write lock using Boost Threads, and I'm having a bit of difficulty mapping the Boost concepts onto the usual ones. A read/write lock should have several states: Locked for reading (multiple threads may lock at once), locked for writing (only one thread may lock, and no threads may be locked for reading at the same time), and unlocked. Ideally it would be nice if an RWL which is locked for reading may temporarily upgrade to locked for writing, then return to the locked for reading state. Boost supports several relevant notions of locking: shared locking, upgrade locking, and exclusive locking. This to me is a confusing distinction. In particular, a shared_mutex seems appropriate as the basis for a RWL, but is lock_upgrade() the equivalent of a write lock and lock_shared the equivalent of a read lock? This is unclear. If "upgrade locking" is not the same as "exclusive locking", then is an upgrade lock actually exclusive? Could someone please clarify this.

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[Statechart] How to decide between post_event and process_event atrun time ?
by Philippe DAVID 22 Jul '14

22 Jul '14

Hi, I have a method in which I want to post/process an event. The thing is, this method can be called from outside the state machine (so I need to call process_event), or indirectly by a reaction of the state machine (in this case I must call post_event since process_event is not reentrant). I don't want to write 2 distinct methods to do this (one that calls post, and the other process), I would much rather prefer adding a 'if' in my method that tells me if I have to call process_event or post_event (if I'm being called indirectly by the state machine or not). Is there a way to do this with statechart ? regards, Philippe

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[asio] resolver::cancel() problem
by Matthew Edwards 14 Mar '14

14 Mar '14

In my application (and a separate test program) it seems as though the cancel() function on the resolver does not work as intended. For async resolves, the cancel functionality should abort them immediately and pass an 'operation aborted' error code to the callback handler. In my tests, I will resolve an invalid domain (this causes the resolve to take a few seconds, to demonstrate the problem), sleep for 100ms, then call cancel on the resolver object. No cancelling actually occurs, and the callback is simply triggered after a few seconds with a "No host found" error code, not the expected operation aborted. Has anyone experienced this before, or know how I might be using the resolver incorrectly?

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[BGL] Having a cost function as weight map
by Maxime van Noppen 06 Sep '13

06 Sep '13

Hi, I can't find how to do this pretty basic thing : having a function instead of a field to compute the cost of edges for various path finding algorithms. I couldn't find the answer in the documentation and Google was of no help. Did I miss something obvious ? Example : ------------------- #include <boost/graph/dijkstra_shortest_paths.hpp> #include <boost/graph/graph_traits.hpp> #include <boost/graph/adjacency_list.hpp> struct my_edge { double cost() const { return cost_ * 2; } double cost_; }; struct my_node { }; int main() { typedef boost::adjacency_list< boost::vecS, boost::vecS, boost::directedS, my_node, my_edge > graph_t; typedef boost::graph_traits<graph_t>::vertex_descriptor vertex_t; graph_t graph; vertex_t v /*= ... */; using boost::weight_map; // Works : boost::dijkstra_shortest_paths(graph, v, weight_map(boost::get(&my_edge::cost_, graph))); // Doesn't compile : //boost::dijkstra_shortest_paths(graph, v, // weight_map(boost::get(&my_edge::cost, graph))); } ------------------- Thanks ! -- Maxime

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Identify cycles in a undirected graph
by NsPx 20 Aug '13

20 Aug '13

Hi all, I use undirected_dfs to detect all cycles in a undirected graph. I detect a cycle with DFSVisitor.back_edge(e,g) but how can I get the list of vertices defining this cycle ? Thanks by advance

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can't get first example in boost tutorial to work
by 7stud 11 Mar '13

11 Mar '13

I'm trying to install boost on mac osx 10.4.7. I followed the tutorial "Getting Started on Unix Variants" found here: http://www.boost.org/doc/libs/1_35_0/ more/getting_started/unix-variants.html Following the instructions in the tutorial, I installed boost in /usr/local as instructed, so my directory structure is: /usr/local/boost_1_34_1/boost But when I run the first example in the tutorial: #include <boost/lambda/lambda.hpp> #include <iostream> #include <iterator> #include <algorithm> int main() { using namespace boost::lambda; typedef std::istream_iterator<int> in; std::for_each(in(std::cin), in(), std::cout << (_1 * 3) << " " ); } I get the error(among others): error: boost/lambda/lambda.hpp: No such file or directory If I change the include path to: #include </user/local/boost_1_34_1/boost/lambda/lambda.hpp> I get the error(among others): error: boost/lambda/core.hpp: No such file or directory But core.hpp is in the lambda directory: /usr/local/boost_1_34_1/boost/lambda$ ls algorithm.hpp control_structures.hpp lambda.hpp bind.hpp core.hpp loops.hpp casts.hpp detail numeric.hpp closures.hpp exceptions.hpp switch.hpp construct.hpp if.hpp I'm using the Xcode 2.4 IDE to run my C++ programs. I also tried to execute the program from the command line with the original include path: #include <boost/lambda/lambda.hpp> but I get the same error: ~/2testing/dir1$ g++ prog1.cpp prog1.cpp:1:35: error: boost/lambda/lambda.hpp: No such file or directory prog1.cpp: In function 'int main()': prog1.cpp:8: error: 'boost' has not been declared prog1.cpp:8: error: expected namespace-name before ';' token prog1.cpp:8: error: '<type error>' is not a namespace prog1.cpp:11: error: '_1' was not declared in this scope I get the same errors again with the full include path: #include </user/local/boost_1_34_1/boost/lambda/lambda.hpp> $ g++ prog1.cpp In file included from prog1.cpp:1: /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:14:33: error: boost/lambda/core.hpp: No such file or directory /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:21:52: error: boost/lambda/detail/operator_actions.hpp: No such file or directory /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:22:61: error: boost/lambda/detail/operator_lambda_func_base.hpp: No such file or directory /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:23:63: error: boost/lambda/detail/operator_return_type_traits.hpp: No such file or directory /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:26:45: error: boost/lambda/detail/operators.hpp: No such file or directory /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:30:46: error: boost/lambda/detail/member_ptr.hpp: No such file or directory prog1.cpp: In function 'int main()': prog1.cpp:8: error: 'boost' has not been declared prog1.cpp:8: error: expected namespace-name before ';' token prog1.cpp:8: error: '<type error>' is not a namespace prog1.cpp:11: error: '_1' was not declared in this scope What path should I be using? Or, should I set an environment variable somewhere?

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Asio and ZeroMQ
by Matthias Vallentin 11 Oct '12

11 Oct '12

A while ago, Maciej Gajewski started an effort to use Asio to observe a ZeroMQ socket [1]. Based on his code, I put together a thin library that wraps the implementation details. Since other have requested a working example, here it is now at github: https://github.com/mavam/bmq Any feedback is highly appreciated. A basic usage example looks like this: #include <boost/asio/io_service.hpp> #include <bmq.h> int main() { boost::asio::io_service io; bmq::context ctx(1); bmq::component c(ctx, io); auto sink = c.add_sink(ZMQ_PAIR, "inproc://x"); c.subscribe(sink, [](bmq::message&& msg) { std::string str(static_cast<char*>(msg.data()), msg.size()); std::cout << str << std::endl; }); auto source = c.add_source(ZMQ_PAIR, "inproc://x"); bmq::message msg(const_cast<char*>("foo"), 3, nullptr); source->send(msg); // Execute message handler. io.poll(); return 0; } At this point, the library is really thin and only provides very rudimentary wrapping of ZeroMQ. In the future, I plan to extend it in order to facilitate applications that build on message-passing. The dataflow abstraction I envision is essentially a directed graph, where nodes represent components and edges communication links. 0mq provides the edges and the Asio handles asynchronous event processing at the component level. The motiviation is that this model lends itself well for scaling out distributed systems over large clusters. Matthias [1] http://permalink.gmane.org/gmane.network.zeromq.devel/9538

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[Sandbox - endian] Why is endian still in sandbox?
by Nathaniel J Fries 07 Oct '12

07 Oct '12

A fairly novel (at least when put up against more intricate labours like asio, filesystem, and their like) project which appears to be finished and would be a very useful companion to existing libraries sits in the sandbox. Is there a reason for this?

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[BGL] vecS for vertex container and vertex index adjustments
by Sergey Mitsyn 03 Oct '12

03 Oct '12

Hi all, I know that while using vecS for vertices one has no vertex iterator stability upon removing vertices. But I have a question if there exists something like vertex _index_ stability. The documentation says that indices for vertices are automatically adjusted so that they are still in contiguous range, but it is not specified how it is done. Is it okay to assume that if a vertex with an index I is removed, then vertices with indices < I have their indices unchanged, while vertices with indices > I have their indices decreased by one? The actual problem is removing all vertices meeting some condition. Is the following code ok? // traverse all vertices and remove those for which predicate // condition_to_remove_vertex returns true. // graph is adjacency_list<.., vecS, ...> vertex_iterator vi = vertices(graph).first, vi_end = vertices(graph).second; while (vi != vi_end) { if (condition_to_remove_vertex(vi, graph)) { vertices_size_type end_index = vertex_index[*vi_end] , vi_index = vertex_index[*vi]; remove_vertex_f(*vi, graph); // vi and vi_end are invalid --end_index; vi = vertices(graph).first + vi_index; vi_end = vertices(graph).first + end_index; // now vi and vi_end are valid again } else ++vi; } This way seems to be more effective than to start iteration again every time a vertex is removed. ------------ Sergey Mitsyn.

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[Range] insert algorithm fails if target is a map
by Robert Jones 11 Sep '12

11 Sep '12

The title says it all really. The failure occurs because the insert algorithm expects the container to provide a 3-arg insert of the form container.insert( position, begin, end ); whereas map's, multimap's and set's insert method only takes two arguments... map.insert( begin, end ); Is this limitation by design? It would be easy to provide specialisations for maps, mmaps and sets, but that would not be a completely general solution. - Rob.

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filesystem directory_iterator run-time error during construction after upgrading to OSX Lion
by Martin Searancke 04 Sep '12

04 Sep '12

I have just upgraded my Mac to Lion and code that worked fine under snow leopard is giving me a run-time exception when constructing a directory_iterator. The error I am getting is "malloc: pointer being freed was not allocated" The line in question that raises this error is: for ( directory_iterator itr( my_path ); itr != end_itr; ++itr ) taken directly from the example and working fine under windows. This is version 1.49 installed with MacPorts. Is this a known problem? I found some vague references to a similar problem in an earlier version of boost but no solution. I have confirmed that I only have 1 copy of the headers and libs on the system and in the correct path. The date stamp on the files matches the last time I did a macports update so this should be the matching library for the header. Please note that I am a real novice to Mac development and have only just started porting code from windows for less than a month. Thanks in advance, Martin

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[Graph] compilation error under Windows but not under Linux
by Gaël de Chalendar 29 Aug '12

29 Aug '12

Hello, I have a compilation error under Windows (Visual C++ 2008) with a code that works well under Linux (gcc 4.6.1 and before). The compilation error is: =========== /FsaAccess16.tcc(833) : error C2784: 'std::pair<graph_traits<G>::in_edge_iterator,graph_traits<G>::in_edge_iterator> boost::in_edges(graph_traits<G>::vertex_descriptor,const boost::subgraph<Graph> &)'ÿ: impossible de d‚duire l'argument modŠle pour 'const boost::subgraph<Graph> &' … partir de 'FrCeaLic2m::Common::FsaAccess::selected_graph_types16::spareGraphType' C:\PROGRA~1\boost\BOOST_~1\boost/graph/subgraph.hpp(432)ÿ: voir la d‚claration de 'boost::in_edges' Z: \Projets\MoteurMultimedia\mm_common\src\common/FsaAccess/FsaAccess16.tcc(778)ÿ: lors de la compilation de la fonction membre '<Inconnu>' de la classe <Inconnu> z: \projets\moteurmultimedia\mm_common\src\common\fsaaccess\FsaAccessReader16.h(118)ÿ: voir la r‚f‚rence … l'instanciation de la classe modŠle 'FrCeaLic2m::Common::FsaAccess::FsaAccess16<graphType>' en cours de compilation with [ graphType=FrCeaLic2m::Common::FsaAccess::selected_graph_types16::spareGraphType ] z: \projets\moteurmultimedia\mm_common\src\common\fsaaccess\FsaAccessSpare16.h(35)ÿ: voir la r‚f‚rence … l'instanciation de la classe modŠle 'FrCeaLic2m::Common::FsaAccess::FsaAccessReader16<graphType>' en cours de compilation with [ graphType=FrCeaLic2m::Common::FsaAccess::selected_graph_types16::spareGraphType ] =========== The line that does not compile is boost::tie(iei,ie_end) = boost::in_edges(commonTarget,m_graph); The function being compiled is declared like that: template <typename graphType > std::pair< const typename boost::graph_traits<graphType>::vertex_descriptor, bool > FsaAccess16<graphType>::findEquivalentInRegister( dicoVertexType tempState ){ ... And here graphType, the type of m_graph is spareGraphType defined by: struct selected_graph_types16 { ... typedef boost::adjacency_list<boost::vecS, boost::vecS, boost::directedS, dicoVertexCountProperty> spareGraphType; ... This is a cmake based project that I compile using qtcreator. I'm a Linux developer and I'm a little bit lost with VC outputs and tools under Windows... Regards, Gaêl -- Gael de Chalendar CEA LIST Centre de Fontenay-aux-Roses Laboratoire Vision et Ingénierie des Contenus (Vision and Content Engineering Laboratory) Bat. 38-2 ; 18, rue du Panorama ; BP 6 92265 Fontenay aux Roses Cedex ; France Tél.:01.46.54.80.18 ; Fax.:01.46.54.75.80 Email : Gael.D.O.T.de-Chalendar.A(a)T.cea.D.O.T.fr

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Re: [Boost-users] asio HTTP Server 3 example memory leak
by admin＠thefireflyproject.us 25 Aug '12

25 Aug '12

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[iostreams] Possible bug in gzip_decompressor?
by Gavin Band 18 Jun '12

18 Jun '12

Dear list, I have been using boost.iostreams to read gzipped files for some time, but recently have run into some problems with files that are compressed using tools other than gzip (namely bgzip from http://samtools.svn.sourceforge.net/viewvc/samtools/trunk/samtools/) Here is the file: $ hexdump -C ../hello.txt.bgz 00000000 1f 8b 08 04 00 00 00 00 00 ff 06 00 42 43 02 00 |............BC..| 00000010 35 00 f3 48 cd c9 c9 d7 51 28 c9 c8 2c 56 00 a2 |5..H....Q(..,V..| 00000020 44 85 92 d4 e2 12 85 b4 cc 9c 54 3d 2e 00 86 1e |D.........T=....| 00000030 ef a4 1c 00 00 00 1f 8b 08 04 00 00 00 00 00 ff |................| 00000040 06 00 42 43 02 00 1b 00 03 00 00 00 00 00 00 00 |..BC............| 00000050 00 00 |..| 00000052 I think this is valid gzip format (based on reading http://www.gzip.org/zlib/rfc-gzip.html) It differs from what you get by compressing the file using the gzip program in two respects: 1. it uses the 'extra' flag (FLG.EXTRA) to add extra data to each block header, and 2. it has two blocks, the second of which is empty. My file reading code is as follows: /* test.cpp */ #include <iostream> #include <boost/iostreams/filtering_stream.hpp> #include <boost/iostreams/filter/gzip.hpp> #include <boost/iostreams/copy.hpp> #include <boost/iostreams/device/file.hpp> int main( int, char** ) { boost::iostreams::filtering_istream stream ; stream.push( boost::iostreams::gzip_decompressor() ) ; boost::iostreams::file_source file( argv[1] ) ; stream.push( file ) ; boost::iostreams::copy( stream, std::cout ) ; } I am using boost 1.48.0 on Ubuntu linux. The compilation is $ g++ -o test -g test.cpp -L /home/gav/Projects/Software/usr/lib -lboost_iostreams-gcc46-mt-1_48 -I /home/gav/Projects/Software/boost_1_48_0 Using gunzip on the above file works fine: $ gunzip -c ../hello.txt.bgz Hello, this is a test file. Using the test program does not: $ ./test ../hello.txt.bgz terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::iostreams::gzip_error> >' what(): gzip error I was able to fix this problem with two code changes in the boost.iostreams implementation, as follows. *Change #1*: at libs/iostreams/src/gzip.cpp:65: change "state_ = s_extra;" to "state_ = s_xlen;" Rationale: without this change, it looks like state s_xlen is never entered so the length of the extra data is not parsed. *Update:* I notice this change was already raised in ticket #5908, and has already been fixed in trunk. * * *Change #2*: at libs/iostreams/src/zlib.cpp:153: change "crc_imp_ = 0;" to "crc_ = crc_imp_ = 0;" Rationale: without this change, an empty block of data does not re-initialise the member variable crc_ of zlib_base. This causes an exception on line 447 of boost/iostreams/filter/gzip.hpp. I confirmed this behaviour a second way, by concatenating two files compressed using gzip, the first nonempty and the second empty. This creates a file which looks like this: $ hexdump -C hello2.txt.gz 00000000 1f 8b 08 00 0d ea b4 4f 00 03 cb 48 cd c9 c9 57 |.......O...H...W| 00000010 28 c9 48 2d 4a e5 02 00 8e 45 d1 59 0c 00 00 00 |(.H-J....E.Y....| 00000020 1f 8b 08 00 18 ea b4 4f 00 03 03 00 00 00 00 00 |.......O........| 00000030 00 00 00 00 |....| 00000034 This file again decompresses with gunzip but not with the program above. Change #2 above fixes this. Could someone take a look at this and let me know if this change is really appropriate? (Or perhaps I'm doing something wrong.) I can create a bug report if desired. Many thanks, Gavin Band.

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[vector, PropertyGraph] Problem declaring a class member of the "vector<int>" type
by Alex Sadovsky 13 Jun '12

13 Jun '12

Hello everyone, > >I am trying to declare, in a header file, a class that has a member of type "vector<double>" (the code is included below). The compiler complains that I haven't included the appropriate namespace (the error message reads, "ISO C++ forbids declaration of ‘vector’ with no type"), and I understand that it is looking for this: > >using namespace boost::numeric::ublas; > >However, I tried putting it in the header file in various places (haven't programmed in C++ in 10 years and couldn't find any online documentation to clarify this specific situation), and still no luck. I am definitely doing something wrong, but cannot reason out the error, as it probably has to do with the specific syntax conventions. Any help is appreciated! > >Thanks, >-Al > >P.S. Code in header file: > >////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// >// File "airspace-graph-rectilinear-edges.h" >typedef char* string; >const int PHYSICAL_SPACE_DIMENSION = 2; >// Information needed about a waypoint used in an airspace: name and physical position >class WaypointConcept{ > private: > using namespace boost::numeric::ublas; > string waypoint_name; > vector<double> waypoint_position_xyh(PHYSICAL_SPACE_DIMENSION); > public: > string GetWaypointName(); > vector<double> GetWaypointPosition(); >} > >class AirspaceGraphConcept PropertyGraphConcept<class Graph, class WaypointConcept, class vertex_index_t>; >typedef Vertex* GraphPathType; >typedef string FlightIDType; >typedef boost::unordered_map<std::FlightIDType, GraphPathType> FlightIDToPathAssignmentType; >////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// > >Code in the .cpp file (which includes the above header file) I am trying to compile: >////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// >#include <boost/lambda/lambda.hpp> >#include <iostream> >#include <iterator> >#include <algorithm> >#include <boost/numeric/ublas/io.hpp> >#include <boost/numeric/ublas/vector.hpp> >#include "airspace-graph-rectilinear-edges.h" > >int main() >{ > using namespace boost::numeric::ublas; > > vector<double> v(3); > for (unsigned i = 0; i < v.size(); ++ i) > v (i) = 2.01*double(i); > > std::cout << v << std::endl; >} >////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// > > > > > > > > > > > > > > > >

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[property_tree] number of sections in an inifile
by Sean Farrow 13 Jun '12

13 Jun '12

Hi: If I have defined: boost::property_tree::ptree IniTree; What is the correct way to determine how many sections there are in an ini file. Should I use count, max_size, m_children or size? Any help appreciated. Cheers Sean.

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accumulator operations
by Olaf Peter 04 Jun '12

04 Jun '12

Hi, I like to collects some stats. There are several data slices where I can partially/separated collect them (each of them). Finaly I like to combine these stats to a single one to get summarized informations. How to? May this work: accumulator_set<..> acc1; accumulator_set<..> acc2; ... accumulator_set<..> acc_all; ... acc1(42); ... acc_all += acc1; ... acc_all += acc2; Because did not found informations about. The same problem woulde be probably for a threaded implementation too. Thanks, Olaf

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[uBlas] Linkage problems in assignment.hpp
by Jérémy Coulon 04 Jun '12

04 Jun '12

Hi, I upgraded to Boost v1.49 recently. I am affected by the following bug : https://svn.boost.org/trac/boost/ticket/6010 According to trac, the bug should be fixed in 1.48, right ? Then why is it still there in 1.49 ? Jeremy

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[multi_array] operator= requires resize - why?
by Markus Werle 04 Jun '12

04 Jun '12

Hi! IMHO the behaviour of operator= for multi_array is a little bit broken. A lot of preconditions required: template <typename ConstMultiArray> multi_array_ref& operator=(const ConstMultiArray& other) { [...] // make sure the dimensions agree assert(other.num_dimensions() == this->num_dimensions()); assert(std::equal(other.shape(),other.shape()+this->num_dimensions(), this->shape())); Besides the fact that I get mad about asserts instead of exceptions (please change this to a way users may choose) why do we have such an odd behaviour here? >From page 1, line 3 of the docs I cite: "The interface design is in line with the precedent set by the C++ Standard Library containers" - this is not true for operator=, since std::<container>::operator= works fine for me all the time _without_ any resize. Could we please change the behaviour of multi_array::operator= to take care of resize where in need to? IMHO operator= should result in a true copy ignoring previous state. Markus

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[boost] [review] Multiprecision review scheduled for June 8th - 17th, 2012
by Jeffrey Lee Hellrung, Jr. 04 Jun '12

04 Jun '12

Hi all, The review of the proposed Boost.Multiprecision library authored by John Maddock and Christopher Kormanyos has been scheduled for June 8th - June 17th, 2012 and will be managed by myself. >From the Introduction: -------- "The Multiprecision Library provides *User-defined* integer, rational and floating-point C++ types which try to emulate as closely as practicable the C++ built-in types, but provide for more range and precision. Depending upon the number type, precision may be arbitrarily large (limited only by available memory), fixed at compile time values, for example 50 decimal digits, or a variable controlled at run-time by member functions. The types are expression-template-enabled for better performance than naive user-defined types." -------- And from the original formal review request from John: -------- Features: * Expression template enabled front end. * Support for Integer, Rational and Floating Point types. Supported Integer backends: * GMP. * Libtommath. * cpp_int. cpp_int is an all C++ Boost licensed backend, supports both arbitrary precision types (with Allocator support), and signed and unsigned fixed precision types (with no memory allocation). There are also some integer specific functions - for Miller Rabin testing, bit fiddling, random numbers. Plus interoperability with Boost.Rational (though that loses the expression template frontend). Supported Rational Backends: * GMP * libtommath * cpp_int (as above) Supported Floating point backends: * GMP * MPFR * cpp_dec_float cpp_dec_float is an all C++ Boost licensed type, adapted from Christopher Kormanyos' e_float code (published in TOMS last year). All the floating point types, have full std lib support (cos sin exp, pow etc), as well as full interoperability with Boost.Math. There's nothing in principal to prevent extension to complex numbers and interval arithmetic types (plus any other number types I've forgotten!), but I've run out of energy for now ;-) Code is in the sandbox under /big_number/. Docs can be viewed online here: http://svn.boost.org/svn/boost/sandbox/big_number/libs/multiprecision/doc/h… -------- I hope everyone interested can reserve some time to read through the documentation, try the code out, and post a formal review, either during the formal review window or before. I expect to conduct the review in the "traditional" manner, i.e., entirely within the regular boost developers' mailing list (boost(a)lists.boost.org) I will send a reminder of review process details closer to the review window. Thanks! - Jeff

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[mpi] multithreaded/funneled messaging
by Brian Budge 03 Jun '12

03 Jun '12

Hi all - Is boost.mpi able to work with MPI_THREAD_MULTIPLE? If so, how is it specified? Thanks, Brian

2 1

[GIL] color_converted_view usage problem
by Marc-Antoine ARNAUD 02 Jun '12

02 Jun '12

Hi guys, I currently working on TuttleOFX projet, and using Boost GIL to perform some image process. I wan't using color_converted_view to process clamping values on a view, witth a specific ColorConvert (CC) functor. But with the actual code [ https://github.com/tuttleofx/TuttleOFX/blob/master/libraries/terry/src/terr…] , the pixel_clamp contructor was corretly called, but our functor (void operator()( const SPixel& src, DPixel& dst ) const) wasn't. Does someone have the same bug ? Are they more documentation anywhere on this function ( I'm refering on this link: http://stlab.adobe.com/gil/html/group___image_view_transformations_color_co… ) Thanks, -- Marc-Antoine

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