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Problem with writing a dijkstra_visitor
by Fabian Buske 09 Aug '05

09 Aug '05

Hi, I'm trying to write a dijkstra visitor, that sets the weight of an egde to the maximum value after assigning it to a minimum spanning tree. The visitor is created according to the bacon sample: template <typename WeightMap> class special_dijkstra_visitor : public boost::default_dijkstra_visitor { public: special_dijkstra_visitor(WeightMap& w):default_dijkstra_visitor(),weight_map_(w){}; template <typename Edge, typename Graph> void edge_relaxed(Edge e, Graph& g) { weight_map_[e] = DBL_MAX; } template <class Edge, class Graph> void edge_not_relaxed(Edge e, Graph& g) { weight_map_[e] = DBL_MAX; } private: WeightMap weight_map_; }; // Convenience function template <typename WeightMap> special_dijkstra_visitor<WeightMap> visit_special_dijkstra(WeightMap w) { return special_dijkstra_visitor<WeightMap>(w); } The graph based on an adjacency matrix with property<edge_weight_t, double> The visitor is called by: property_map<Graph, edge_weight_t>::type weightmap = get(edge_weight, g); prim_minimum_spanning_tree(g, root, &p[0], distance, weightmap, indexmap, visitor(visit_special_dijkstra(weightmap))); The linux gnu 3.4.4 compiler gives the following error messages *snip template instance error messages* /zeug/study/OpenMSLibs/CGAL-3.1-gcc-3.4.4/include/boost/graph/dijkstra_shortest_paths.hpp:120: error: ` edge_relaxed' undeclared (first use this function) /zeug/study/OpenMSLibs/CGAL-3.1-gcc-3.4.4/include/boost/graph/dijkstra_shortest_paths.hpp:122: error: ` edge_not_relaxed' undeclared (first use this function) /zeug/study/OpenMSLibs/CGAL-3.1-gcc-3.4.4/include/boost/graph/dijkstra_shortest_paths.hpp:143: error: ` finish_vertex' undeclared (first use this function) ... I'm wondering, cause I thought deriving from default_dijkstra_visitor ensures that finish_vertex is allready implemented. Compiling the bacon sample on the same graph works fine. So I'm really confused. Any hints for debugging the code? Thanks a lot. Regards Fabian

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Boost regression notification (2005-08-09)
by Douglas Gregor 09 Aug '05

09 Aug '05

Boost regression test failures ------------------------------ Report time: 2005-08-09T14:43:35Z This report lists all regression test failures on release platforms. Detailed report: http://engineering.meta-comm.com/boost-regression/CVS-RC_1_33_0/developer/i… 0 failure in 0 library:

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Re: [boost] Improved boost::any
by Eyal Farago 09 Aug '05

09 Aug '05

I read the code project article and I have few comments: 1. why optimize only for types smaller than void*? you can specify a different max size (bigger than sizeof(void*) and probably a product of it with another integer) to achieve even better results. 2. the implementation is pretty messy and quite dangerous, I'm quite sure it wouldn't compile/work on multimple platforms, and the first one that pops into my mind is solaris which enforce proper alighnment... 3. it is possible to borrow some of the tricks boost::variant uses to achieve correct allignment. i.e. using a boost::variant<void*, char[/*buffer size here*/]> and when the buffer is used store the actual alignment in a member variable of the class. 4. if 3 isn't possible, look at boost::function implementation, but I'm not sure if they're using a buffer or a simple union with a void* and few other types... eyal. -----Original Message----- From: boost-bounces(a)lists.boost.org [mailto:boost-bounces@lists.boost.org]On Behalf Of christopher diggins Sent: Tuesday, August 09, 2005 12:49 AM To: Boost mailing list Subject: [boost] Improved boost::any I have developed a type very similar to boost::any which requires less memory and significantly reduces the number of allocations / deallocations. If anyone is interested I have posted a brief article about it at CodeProject http://www.codeproject.com/useritems/dynamic_typing.asp and I have uploaded the source to the vault ( http://boost-sandbox.sourceforge.net/vault/index.php ). Is there any interest? Christopher Diggins http://www.cdiggins.com _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost

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Re: [boost] Improved boost::any
by felipe 09 Aug '05

09 Aug '05

hello and good day, Yes, this is actually not unlike the my own implementation of "any". But rather than limit myself to objects that fit in sizeof(void *) bytes, I keep an aggregate member whose size is governed by a template parameter with a default value of sizeof(void *). This way I can arbitrarily specify the mininum size at which objects are heap-allocated. I think this is probably the way to go for discriminant unions.. the typelist solution is just to messy for my tastes, and boost::any is too consumptive. Anyone interested? sincerely, Phillip On Tue, 09 Aug 2005 01:49:45 +0200, <boost-request(a)lists.boost.org> wrote: > Message: 19 > Date: Mon, 08 Aug 2005 18:48:39 -0400 > From: christopher diggins <cdiggins(a)videotron.ca> > Subject: [boost] Improved boost::any > To: Boost mailing list <boost(a)lists.boost.org> > Message-ID: <016001c59c6b$51e3e250$2b792518@heronnest> > Content-Type: text/plain; format=flowed; charset=iso-8859-1; > reply-type=original > I have developed a type very similar to boost::any which requires less > memory and significantly reduces the number of allocations / > deallocations. > If anyone is interested I have posted a brief article about it at > CodeProject http://www.codeproject.com/useritems/dynamic_typing.asp and I > have uploaded the source to the vault ( > http://boost-sandbox.sourceforge.net/vault/index.php ). Is there any > interest? > Christopher Diggins > http://www.cdiggins.com > ----------------------------- -- Using Opera's revolutionary e-mail client: http://www.opera.com/m2/

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Re: [boost] cross_iterator
by BARTLETT, Peter, FM 08 Aug '05

08 Aug '05

>Alex wrote: >[cross_iterator] >Please take a look and let me know what you think. A great start but, if I understand correctly, there is a significant difference with how zip_iterator works. The zip_iterator's dereference method returns a tuple of references to the underlying values, whereas your cross_iterator just returns the tuple of iterators themselves. Thus to use cross_iterator with standard algorithms, the user would have to provide a function object that acts on iterators rather than values which is unusual and unintuitive. Thus to me it seems like cross_iterator needs to borrow much of the TMP code from the detail of zip_iterator (assuming the community is happy with how that class works). Conceptually the two classes only differ in the ++ and -- operators. Pete Bartlett *********************************************************************************** The Royal Bank of Scotland plc. Registered in Scotland No 90312. Registered Office: 36 St Andrew Square, Edinburgh EH2 2YB. Authorised and regulated by the Financial Services Authority This e-mail message is confidential and for use by the addressee only. If the message is received by anyone other than the addressee, please return the message to the sender by replying to it and then delete the message from your computer. Internet e-mails are not necessarily secure. The Royal Bank of Scotland plc does not accept responsibility for changes made to this message after it was sent. Whilst all reasonable care has been taken to avoid the transmission of viruses, it is the responsibility of the recipient to ensure that the onward transmission, opening or use of this message and any attachments will not adversely affect its systems or data. No responsibility is accepted by The Royal Bank of Scotland plc in this regard and the recipient should carry out such virus and other checks as it considers appropriate. Visit our websites at: http://www.rbs.co.uk/CBFM http://www.rbsmarkets.com ********************************************************************************

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cross_iterator
by Alex Mendes da Costa 08 Aug '05

08 Aug '05

Hi folks, A cross_iterator is to a zip_iterator as a cross_product is to a dot_product. For example, given two sequences { a, b }, { 1, 2 }, the sequence of tuples generated by a cross_iterator would be { ( a, 1 ), ( b, 1 ), ( a, 2 ), ( b, 2 ) }. I've put my implementation of cross_iterator in the sandbox (cross_iterator.zip @ http://boost-sandbox.sourceforge.net/vault/) There's no documentation yet, but I've included a sample file that demonstrates how to use the new iterator. Please take a look and let me know what you think. Alex

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[Range] Doc typo [in 1.33.0 RC2]
by Pablo Aguilar 08 Aug '05

08 Aug '05

In the FAQ page, the first answer says: "... that a sub_range do propagate const-ness" ^^ I believe it should say "does" Pablo

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Boost regression notification (2005-08-08)
by Douglas Gregor 08 Aug '05

08 Aug '05

Boost regression test failures ------------------------------ Report time: 2005-08-08T14:56:20Z This report lists all regression test failures on release platforms. WARNING: The following libraries have failing regression tests but do not have a maintainer on file. Once a maintainer is found, add an entry to libs/maintainers.txt to eliminate this message. pool Detailed report: http://engineering.meta-comm.com/boost-regression/CVS-RC_1_33_0/developer/i… 19 failures in 4 libraries: lambda (15) pool (1) rational (2) wave (1) |lambda| algorithm_test: vc-7_1 bind_tests_advanced: vc-7_1 bind_tests_simple: vc-7_1 bind_tests_simple_f_refs: vc-7_1 bll_and_function: vc-7_1 constructor_tests: vc-7_1 control_structures: vc-7_1 exception_test: vc-7_1 extending_rt_traits: vc-7_1 is_instance_of_test: vc-7_1 lambda_cast_test: vc-7_1 member_pointer_test: vc-7_1 operator_tests_simple: vc-7_1 phoenix_control_structures: vc-7_1 switch_construct: vc-7_1 |pool| test_pool_alloc: vc-7_1 |rational| rational_example: vc-7_1 rational_test: vc-7_1 |wave| testwave: vc-7_1

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Boost Library with Socket++ Library :
by Mottengte, Rajeev Kumar 08 Aug '05

08 Aug '05

Hi I tried to use boost library along with Socket++ for network serialization. I have created a socket++ class osockinet which is derived from iostream. I have given this class to boost archive constructor instead of the normal fstream class for archive to redirect to network. Rest of the code is same. I am getting segmentation fault. Can anybody help me on this. It is in Fedora Linux. ThanX & Rgds Rajeev

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Error in Boost.MultiIndex Examples documentation
by Michael Goldshteyn 08 Aug '05

08 Aug '05

Example 6: complex searches and foreign keys See source code. This program illustrates some advanced techniques that can be applied for complex data structures using multi_index_container. Consider a car_model class for storing information about automobiles. On a first approach, car_model can be defined as: struct car_model { std::string model; std:string manufacturer; int price; }; This definition has a design flaw that any reader acquainted with relational databases can easily spot: The manufacturer member is duplicated among all cars having the same manufacturer. --- This definition also has a syntax error that any C++ programmer can easily spot! :) Mike

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