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Re: [Boost-users] [boost] BGL - cycles in an undirected graph
by Aaron Windsor 27 Jul '06

27 Jul '06

On 7/20/06, Michal <simecek(a)gmx.de> wrote: > my task is to find cycles in an undirected graph and to assign a cycle id > to each > vertex in this cycle. It is still a bit more complicated, because I do not > need just the simple cycles, but all simple cycles which are sharing > edges, must > get the same cycle id. > > I think this problem is already solved somewhere, but I cann not find the > right > approach, thus I am asking here if somebody have an idea how to solve it > best > with BGL. Michal, If you want to label the edges of a graph such that (1) any two edges that are on a simple cycle together get the same label, and (2) any two edges not on any cycle together get distinct labels then you simply want to find the biconnected components of the graph - there's a way to do this in linear time using depth-first search, and the algorithm is in the BGL: http://www.boost.org/libs/graph/doc/biconnected_components.html However, the fact that you said that you want to label all vertices in the graph with a distinct label subject to condition (1) above is a little confusing - you can have two cycles that don't meet in any edges but share a common vertex, and in that case, which of the two labels would you want to use for that vertex? Aaron

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[mpl] A partioning unique/non-unique algorithm
by Eric Lemings 27 Jul '06

27 Jul '06

Greetings, How would you combine the boost::mpl::partition and boost::mpl::unique algorithms such that an element that is not placed into the first inserter (for unique elements) is placed into the second inserter (for non-unique elements)? Thanks, Eric.

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error in compiling lambda on solaris
by Mr Abhinav Rai 26 Jul '06

26 Jul '06

I am trying to compile C++ code with lambda included. I am using following version of compiler on Solaris: CC: Sun C++ 5.5 Patch 113817-12 2005/03/08 I get following compile error: /boost/lambda/detail/is_instance_of.hpp", line 90: Error: "{" expected instead of ">" Does this version of solaris compiler not able to compile lambda? are there any defines needed to fix this? __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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Re: [Boost-users] [serialization] basic_xml_iarchive tag checkingbugs
by Todd Greer 26 Jul '06

26 Jul '06

Robert Ramey wrote: Todd Greer wrote: >> 1. The sense of the check of the flags against no_xml_tag_checking is >> reversed. By default, checking of xml tag names is not done, contrary >> to the documentation. If no_xml_tag_checking is passed in as a flag, >> tag checking is enabled. >> My recommended fix for (1) would be to change no_xml_tag_checking to >> check_xml_tags, and to change the documentation to reflect this. While >> the more obvious solution would be to simply fix the comparison, this >> would introduce a silent behavioral change. My recommended fix will >> fail to compile for those that have specified no_xml_tag_checking, >> thus alerting them to the change. > I prefer the more obvious fix as I don't want to change the docs and all > the other switches are no_... I have no objection to that. >> My recommended fix for (2) is to replace the excerpted code with: >> if(0 != (this->get_flags() & check_xml_tags) && rv.object_name != >> name) > > Hmmm - don't we have the same problem here? That is if the object name > read is larger than "name" we could still overflow something. In this case, rv.object_name is a std::string. std::string defines an operator!=(string const& a, char const* b) that has well defined semantics regardless of the lengths of a and b. It just requires that b is a valid c-style string. -- Todd Greer <tgreer <at> affinegy dot com> Senior Software Developer, Affinegy LLC

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boost lambda with proxy reference object
by Nathan Thomas 26 Jul '06

26 Jul '06

Hi all, I'm trying to use boost lambda to aggregate several functor calls together in one pass over my data with a std::for_each(..) (using bind and the lambda comma operator). I'm running into problems because I use an iterator (over type T) where the dereference operator doesn't return a T& but instead an object of type proxy<T>. This proxy class handles marshaling the object from another address space & setting up a temporary copy on its construction and subsequently writes back on destruction. Lambda expects (as it should) a T& from the deference attempt to invoke functors which are set to expect the proxy type. Is there a template I can specialize for this case or some type I could but am not reflecting out of my iterator class to make this work. Or is there better way to write this iterator that would allow me to properly pass a T& while still allowing some pre & post processing on the dereference? Thanks for you time / help, --Nathan Thomas Texas A&M University

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Re: [Boost-users] XML Serialization Traits Question
by William Bardon 26 Jul '06

26 Jul '06

Robert, Thanks for the example; it helped clear up some uncertainty about the template arguments in the derived class. Regarding save_override, I see where specialized versions for the different trait types are defined in basic_xml_oarchive.ipp. I also see that save_override is called from the operator<< redefinition in interface_oarchive.hpp. What I'm missing is the link between serializing a user-defined class object and the traits of that object. template<class Archive> BOOST_ARCHIVE_OR_WARCHIVE_DECL(void) basic_xml_oarchive<Archive>::save_override(const version_type & t, int) { int i = t.t; // extra .t is for borland write_attribute(VERSION(), i); } This function already displays a version attribute in the XML. How do I make sure this is called for every element? I'm sorry, but I can't figure out how to modify chain of control to force output of class traits. Starting in oserializer.hpp, boost::archive::save<Archive,T> calls static save_non_pointer_type<Archive, T>::invoke calls serialize_adl calls boost::serialization::serialize<Archive, T> calls access::serialize calls myClass::serialize<Archive> (Archive& ar, unsigned int version) There is also a function oserializer<Archive,T>::save_object_data that calls serialize_adl, but I can't find anything that calls it. The struct save_non_pointer_type<Archive, T> in oserializer.hpp may be the key, but I'm not sure how it works. In oserializer.hpp, struct save_non_pointer_type<Archive,T>::save_standard::invoke calls Archive::save_object, but I do not see an implementation of the function anywhere: $ find /usr/include/boost -type f -exec grep -H save_object {} \;| grep -v save_object_ | more /usr/include/boost/archive/polymorphic_oarchive.hpp: virtual void save_object( /usr/include/boost/archive/detail/oserializer.hpp: ar.save_object(& t, oserializer<Archive, T>::instantiate()); /usr/include/boost/archive/detail/basic_oarchive.hpp: void save_object( /usr/include/boost/archive/detail/polymorphic_oarchive_impl.hpp: virtual void save_object( /usr/include/boost/archive/detail/polymorphic_oarchive_impl.hpp: ArchiveImplementation::save_object(x, bos); I'd appreciate any suggestions. Am I even looking in the right place? Thanks in advance, Bill -----Original Message----- From: boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Robert Ramey Sent: Wednesday, July 26, 2006 12:14 PM To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] XML Serialization Traits Question "William Bardon" <wbardon(a)cabcds.org> wrote in message news:C73E689C9FCF884B9A550ECFADA0721C087D3E@exchange.cab-cds.org... I have read both the Boost Serialization online documentation and the archives of the Boost-Users mailing list looking for guidance, but I haven't found anything relevant. I see how to use BOOST_CLASS_TRACKING and BOOST_CLASS_IMPLEMENTATION to remove version tracking attributes from the XML tags. Usage of these macros does a lot more than remove attributes from the tags. I want to go in the opposite direction. I notice that the class_id and version attributes only appear the first time an object of a particular class is serialized. I want to force the version attribute to appear in every object's attribute list. Do I need to derive a custom archive to do this? yes I have looked at the source code for serialization, but I have trouble plowing through all of the macros, template expansions, and overloaded functions to locate the specific part that controls whether class traits are stored as attributes in a particular XML tag. I sympathize - its hard to follow. And I wrote it. Here are some hints: a) look at demo_fast_archive.cpp to see a model of how one can derive from an existing archive. b) You'll want to derive from xml_oarchive_impl<...> to create my_xml_oarchive c) add a "save_override" function to my_xml_oarchive which replaces the "save_override" function in basic_xml_oarchive.ipp. Implement this using functions defined basic_xml_oarchive.ipp Good luck - Robert Ramey Thanks in advance, Bill _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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[serialization] basic_xml_iarchive tag checking bugs
by Todd Greer 26 Jul '06

26 Jul '06

Hi, While developing skip_xml_iarchive, I noticed to bugs in basic_xml_iarchive::load_end(). 1. The sense of the check of the flags against no_xml_tag_checking is reversed. By default, checking of xml tag names is not done, contrary to the documentation. If no_xml_tag_checking is passed in as a flag, tag checking is enabled. 2. If tag checking is enabled, and a tag name is encountered that is longer than the name passed in, the name string is accessed past the end of the array. In the expression "name[this->This()->gimpl->rv.object_name.size()]", the index is the size of the encountered name, and could be arbitrarily large. The relevant portion of basic_xml_iarchive::load_end() is included here: if(0 != (this->get_flags() & no_xml_tag_checking)){ if(0 != name[this->This()->gimpl->rv.object_name.size()] || ! std::equal( this->This()->gimpl->rv.object_name.begin(), this->This()->gimpl->rv.object_name.end(), name ) My recommended fix for (1) would be to change no_xml_tag_checking to check_xml_tags, and to change the documentation to reflect this. While the more obvious solution would be to simply fix the comparison, this would introduce a silent behavioral change. My recommended fix will fail to compile for those that have specified no_xml_tag_checking, thus alerting them to the change. My recommended fix for (2) is to replace the excerpted code with: if(0 != (this->get_flags() & check_xml_tags) && rv.object_name != name) The Boost FAQ recommends posting bug reports to the mailing list. Let me know if you would like for me to submit this to the bug repository. -- Todd Greer <tgreer <at> affinegy dot com> Senior Software Developer, Affinegy LLC

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Re: [Boost-users] [serialization] Skipping unexpected elements inXMLarchive
by Todd Greer 26 Jul '06

26 Jul '06

Robert Ramey wrote: > Sounds to me that others might find this useful. How about making a > little write up, and maybe a small test/demo, zipping it up and uploading > to the serialization section of the boost vault? I've uploaded skip_xml_iarchive.zip to the vault in serialization. I've fixed several issues from the version I posted here, and have added a bit of testing and explanation. I hope that people find it useful. Please let me know if you have any questions, or find any problems. If you do find it useful, please let me know that as well. -- Todd Greer <tgreer <at> affinegy dot com> Senior Software Developer, Affinegy LLC

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Re: [Boost-users] how to see the actual value of a'boost::optional<__int64>' in VS2005 debugger
by David Klein 26 Jul '06

26 Jul '06

boost-users-bounces(a)lists.boost.org wrote: > Hi Catherine, > > I am sorry that I don't have any idea about a solution to > your problem. Instead, I myself have a problem to ask for > help to solve. If you happen to know anything about it and > would kindly to help me, I would appreciate it very much. > > I am trying to port Bayes++ into a Visual C++ 2005 project. > The version of Boost library is the latest ( v1.33.1). > However, I came cross a C2064 error that tells "term does not > evaluate to a function taking 0 arguments" when I was > compiling the BayesFilter project, which integrates Boost > header libraries. The error referred to the sentence > > BOOST_UBLAS_INLINE > const_iterator (const iterator &it): > container_const_reference<self_type> (it ()), it_ (it.it _) {} > > at line 293 in file "boost_1_33_1\boost\numeric\ublas\vector.hpp". > > I guess that the problem is related to an incompatibility > between Visual C++ 2005 and the Boost C++ package, and might > be cracked by setting appropriate VC 2005 compiling options > or Boost C++ #dehine's. But I don't have any right ideas to > do so. If you could help, it will be very helpful for me. > > Sincerely, > > Jason Zhang > hi jason, see http://thread.gmane.org/gmane.comp.lib.boost.ublas/2472/focus=2472. btw: you better post UBLAS related questions to the ublas mailing list (ublas <at> lists.boost.org) -- HTH dave

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XML Serialization Traits Question
by William Bardon 26 Jul '06

26 Jul '06

I have read both the Boost Serialization online documentation and the archives of the Boost-Users mailing list looking for guidance, but I haven't found anything relevant. I see how to use BOOST_CLASS_TRACKING and BOOST_CLASS_IMPLEMENTATION to remove version tracking attributes from the XML tags. I want to go in the opposite direction. I notice that the class_id and version attributes only appear the first time an object of a particular class is serialized. I want to force the version attribute to appear in every object's attribute list. Do I need to derive a custom archive to do this? I have looked at the source code for serialization, but I have trouble plowing through all of the macros, template expansions, and overloaded functions to locate the specific part that controls whether class traits are stored as attributes in a particular XML tag. Thanks in advance, Bill

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