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Error In undirected subgraph with no parallel edges
by Sandeep Gupta 28 Mar '09

28 Mar '09

Hi, I am using following declaration to define subgraphs over undirected graph such that parallel edges are disallowed: typedef boost::adjacency_list<vecS, setS, undirectedS, property<vertex_index_t,int>, property<edge_index_t,int> > ImplGraph_t; typedef boost::subgraph<ImplGraph_t> embeddedGraph_t; that is use setS for EdgeList instead of listS. However when I call the function local_to_global over the subgraph i end up following errors: /home/sandeep/Computing/boost_1_38_0/boost/graph/subgraph.hpp:147: error: passing ‘const std::vector<void*, std::allocator<void*> >’ as ‘this’ argument of ‘typename std::_Vector_base<_Tp, _Alloc>::_Tp_alloc_type::reference std::vector<_Tp, _Alloc>::operator[](size_t) [with _Tp = void*, _Alloc = std::allocator<void*>]’ discards qualifiers /home/sandeep/Computing/boost_1_38_0/boost/graph/subgraph.hpp:147: error: invalid conversion from ‘void*’ to ‘unsigned int’ /home/sandeep/Computing/boost_1_38_0/boost/graph/subgraph.hpp:147: error: initializing argument 1 of ‘typename std::_Vector_base<_Tp, _Alloc>::_Tp_alloc_type::reference std::vector<_Tp, _Alloc>::operator[](size_t) [with _Tp = void*, _Alloc = std::allocator<void*>]’ Please find the full code that creates the above scenario. Appreciate any help. -Thanks sandeep ///////////////-----------------------Undirected_Subgraph.cpp----------------------------- #include <boost/graph/subgraph.hpp> #include <boost/graph/adjacency_list.hpp> using namespace boost; typedef boost::adjacency_list<vecS, hash, undirectedS, property<vertex_index_t,int>, property<edge_index_t,int> > ImplGraph_t; typedef boost::subgraph<ImplGraph_t> embeddedGraph_t; int main() { embeddedGraph_t G; typedef graph_traits<embeddedGraph_t>::vertex_descriptor vertex_t; vertex_t v; embeddedGraph_t& G1 = G.create_subgraph(); G.local_to_global(v); return 0; }

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[filesystem] detecting hidden files?
by Kenny Riddile 28 Mar '09

28 Mar '09

Does the filesystem library allow you detect whether a path refers to a hidden file or not?

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Re: [boost] [gsoc]built-in support for dictionary words
by kannan venkat 28 Mar '09

28 Mar '09

i got a lot of valuable comments & suggestions . Thanks a lot!! yes bloom filters is the best option for checking if the word is present & for substrings suffix trees should do the trick as Phil Endecott suggested. Inbuilt SpellCheck was a great idea which has practical necessity.I shall try to implement if it can be done within the given period. I shall soon post another idea i had been workin on.

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Can a Boost library use a component like GMP and mfpr that have a LGPL license ?
by Paul A. Bristow 28 Mar '09

28 Mar '09

I am raising this issue for discussion because it seems to me that it is important to resolve this issue before development of the GTL library by Lucanus Simonson and others. I suspect this is not the only time this will crop up, especially with the two very well developed and refined 'big' multiprecision number libraries, GMP (http://gmplib.org) and mfpr (www.mfpr.org) Boost lacks any equivalent libraries (apart from some un reviewed, but probably functional, big integer offerings). GMP and mfpr have already been used within John Maddock's Boost.Math library, but only to calculate extremely accurate reference values, so *users* do not have to use GMP and mfpr. Fernando Cacciola wrote "While in the case of GTL, it is technically up to the user to pick up "their own" multiprecision number types, they actually can't do that without an external non-boost library since such number types do not exists in the SCL." I agree that it would be unfortunate to re-invent the wheel to produce our own (probably inferior) version of these components. So what do we do? Might we enter into discussion with GMP and mfpr developers to get explicit permission to package their library within Boost? IANAL but I feel this issue should be resolved and a decision recorded. Paul --- Paul A. Bristow Prizet Farmhouse Kendal, UK LA8 8AB +44 1539 561830, mobile +44 7714330204 pbristow(a)hetp.u-net.com

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[Review Request] Msm
by Christophe Henry 27 Mar '09

27 Mar '09

Hi, Msm v1.20 has now been stable for some time and managed to survive a fair number of tests, so I would like to request a formal review. The review-ready version can be found: - in the Vault: http://www.boostpro.com/vault/index.php?direction=0&order=&directory=Msm& - or better (in case of bugfixes), in the sandbox: https://svn.boost.org/svn/boost/sandbox/msm/ . You will find there the Review version under /tags/version-1.20, the most current version at the same level under /boost (or /libs for the doc). Thanks, Christophe

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[Boost.Config] Using <cstddef> instead of <utility> for std lib detection
by David Deakins 27 Mar '09

27 Mar '09

I am in the process of migrating our VeecoFTC regression tests from VC8 and STLport 5.1 to VC9 and STLport 5.2. While working on this, I have experimented with turning on STLport's _STLP_USE_BOOST_SUPPORT macro. When this macro is defined, STLport will pull in the Boost.TypeTraits header files instead of its own type traits implementations. It also suppliments a few of the standard headers (memory and functional) with Boost-based TR1 functionality much like Boost.TR1 does. However, similar to some of what Boost.TR1 had to deal with, some caution is required to avoid circular dependencies in the headers. One area where this tends to come up is in detecting the standard library in use in Boost.Config. Currently config/select_stdlib_config.hpp and config/stdlib/stlport.hpp include <utility> to determine what std library is provided. However, <utility> can tend to pull in some code that wants type traits and thus may circularly pull in Boost. One convenient way to resolve this would be to use the much simpler <cstddef> header instead of <utlity> to determine the std lib. Is this a reasonable change to make or is there something special about using <utility> in the select_stdlib_config code? -Dave

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[gsoc] Status
by troy d. straszheim 27 Mar '09

27 Mar '09

We have 9 proposals. Four of these are for the devector idea: students who have filed these overlapping proposals are encouraged to take the initiative, come up with some ideas and discuss them on the list. We have enough mentors, but it isn't clear that each proposal will match up well with an individual mentor. More mentors welcome to apply. Currently we have no way to make the current set of proposals visible to the general community. I've filed a bug with google and have reason to hope this will get resolved soon. Until then only accepted mentors can see the full list. :/ Students who are working on a proposal who haven't submitted it yet are encouraged to get a draft together, put it up on a webpage or wiki someplace, solicit comments, and refine. This can only help your chances. -t

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[Boost][Random] Question on random_test.cpp
by n1driver＠charter.net 27 Mar '09

27 Mar '09

The following is an excerpt from the random_test.cpp file (part of the instantiate_urng function): urng2 = urng; { // narrow stream first std::ostringstream file; file << urng; // move forward urng(); // restore old state std::istringstream input(file.str()); input >> urng; // std::cout << file.str() << std::endl; #if !defined(BOOST_MSVC) || BOOST_MSVC > 1300 // MSVC brokenness // advance some more so that state is exercised for(int i = 0; i < 10000; ++i) { urng(); urng2(); } BOOST_CHECK(urng == urng2); #endif // BOOST_MSVC } My concern is that when a random number generator with an underlying double type (like fibonacci607) is stored to the stream and then pulled back out, then precision may be lost, and the underlying data is not guaranteed to be the same. If a double is written out to a stream in decimal form and then read back in the value may be changed. Am I missing some sort of language guarantee that this is supposed to work? I've tried this on AIX and the test failed at this point for fibonacci607 because some (but not all) of the underlying doubles had changed after the object was stored and retrieved. Thanks!

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[gsoc][graph] Hierarchical graph layout algorithms.
by Daniel Arbelo 27 Mar '09

27 Mar '09

Hello, I'm a student interested in adding hierarchical layout algorithms as mentioned in https://svn.boost.org/trac/boost/wiki/soc2009#Hierarchicalgraphlayoutalgori… . Is there someone available I could discuss the details for it? Are there any prospective mentors for this proposal? I'm mostly looking to discuss a proper scope for this and what Boost needs or expects from a proposal in this area. Daniel Arbelo Arrocha

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boost::interprocess -- How do I construct a anonymous object ?
by Oncaphillis 27 Mar '09

27 Mar '09

Hi, I'm using boost::interprocess (1.37) and would like to construct a couple of anonymous objects. The idea is to construct a named object via Object *o segment.find_or_construct<Object>("theObject")(); and let this one dynamically construct a couple of other objects to which it holds offset_ptrs. On destruction one could simply use segment.destroy_ptr<Object2>( myOffset.get() ); to get rid of these objects. This works fine with objects I constructed with segment.construct<Object2>("GAGA NAME")(); but the reference by name seems to be unnecessary. The doc tells something about constructing and creating of anonymous objects but so far I only find allocators or copy constructors for anonymous objects. Thanks you .... O.

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