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Sperical / geo coordinates question: crossing anti-meridian
by John Lilley 20 Feb '13

20 Feb '13

I am trying to determine if boost.geometry handles certain cases of spherical coordinates. Suppose you have county outlines of Alaska. The Aleutian Islands chain crosses the anti-meridian, and so contains latitudes that are in the ranges [ 180 - delta ... 180 ] and [ -180, -180 + delta ] where delta is < 20 degrees or so. Simple (2D planar) point-in-polygon and polygon intersection algorithms fall down on these cases due to anti-meridian crossings and flipping between +/- values. Does Boost geometry deal with these issues "correctly"? I put correctly in quotes because there is some real ambiguity in the coordinate system (maybe the polygon really does wrap around the world?), but one could apply a "minimum perimeter" heuristic and normalize the polygons before performing the computation by moving the [ 180 - delta ... 180 ] range over to [ -180 - delta ... -180 ] or vice-versa. Thanks, john

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[Atomic] [Tread] Proposal for, Synchronized<T>
by John M. Dlugosz 19 Feb '13

19 Feb '13

On 2/19/2013 4:02 PM, boost-users-request-at-lists.boost.org |Boost/Allow to home| wrote: > Subject: Re: [Boost-users] [Atomic] [Tread] Proposal for > Synchronized<T> > Message-ID:<5123C32D.9020700(a)wanadoo.fr> > Content-Type: text/plain; charset="iso-8859-1"; Format="flowed" > > Le 19/02/13 17:58, Gabriel Bizzotto a ?crit : >> >Hi ! >> > >> >I've created two simples classes that helped me avoid data races when >> >sharing objects among threads. >> > >> >The idea is to declare objects that need for synchronization as >> >Synchronized<T>, which holds a T and a mutex. To use the T, a Get >> >function has to be called that returns a proxy, which holds a pointer >> >to the T and a scoped lock on the mutex. The proxy defines operator-> >> >and operator* to give access to the T. To have acces to the T, one has >> >to create the proxy. As long as the proxy exists, the mutex associated >> >with the T is locked, effectively preventing use by other threads. I have one that does reader/writer locking. I'll pass it along for comparison along with design notes (it was done partially for teaching), if it's OK to send a zip file to you. —John

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[property_map] constructor of vector_property_map
by Andreas Fabri 19 Feb '13

19 Feb '13

Hello, Why is initial_size in the constructor __________________________________________________________________ vector_property_map(unsigned initial_size, const IndexMap& index = IndexMap()) This constructor version allows to specify maximum index of element that will be stored. Correct number will improve performance, but semantic is always the same. Source: http://www.boost.org/doc/libs/1_53_0/libs/property_map/doc/vector_property_… __________________________________________________________________ not std::size_t, for the simple reason that the std::vector might be bigger. best regards, andreas -- Andreas Fabri, PhD Chief Officer, GeometryFactory Editor, The CGAL Project phone: +33.492.954.912 skype: andreas.fabri

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compiling error from code using boost::bind code in Vs2010
by Miguel Carvajal 19 Feb '13

19 Feb '13

hello, actually i am using boost 1.48 on vs2010 and the following code does not compile on boost #include<boost/bind.hpp> #include<boost/function.hpp> using namespace boost; class A { public: void evaluate(function<VectorClass(VectorClass,double)> f) }; class B { A a; public; VectorClass f(VectorClass,double); void test() { a.evaluate(bind(f,this,_1,_2)); } }; Any help?

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[Atomic] [Tread] Proposal for Synchronized<T>
by Gabriel Bizzotto 19 Feb '13

19 Feb '13

Hi ! I've created two simples classes that helped me avoid data races when sharing objects among threads. The idea is to declare objects that need for synchronization as Synchronized<T>, which holds a T and a mutex. To use the T, a Get function has to be called that returns a proxy, which holds a pointer to the T and a scoped lock on the mutex. The proxy defines operator-> and operator* to give access to the T. To have acces to the T, one has to create the proxy. As long as the proxy exists, the mutex associated with the T is locked, effectively preventing use by other threads. For more details and examples, I've already published the classes here http://codereview.stackexchange.com/questions/15632/force-locking-for-threa… I find the scheme general purpose enough to fit the Atomic lib, or perhaps Thread. Please manifest yourselves if there is any interest in such device. Thx. Gabriel ++++++[>+++[>++++>++++++<<-]<-]>>-.>---.-------..>++++[<++++>-]<+. WebRep Classificação geral Este site não tem classificação (número de votos insuficientes) WebRep Classificação geral Este site não tem classificação (número de votos insuficientes) WebRep Classificação geral Este site não tem classificação (número de votos insuficientes) WebRep Classificação geral Este site não tem classificação (número de votos insuficientes) WebRep Classificação geral Este site não tem classificação (número de votos insuficientes) WebRep Classificação geral Este site não tem classificação (número de votos insuficientes) WebRep Classificação geral Este site não tem classificação (número de votos insuficientes) WebRep Classificação geral Este site não tem classificação (número de votos insuficientes) WebRep Classificação geral Este site não tem classificação (número de votos insuficientes)

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[Property Tree] special character in XML tag
by Gábor Márton 19 Feb '13

19 Feb '13

Hi, I have the following property tree, dumped in INFO format: CudbAppServiceId=1 { userLabel "" sqlAppSrvPlSchema identities-pl.sql CudbAppServiceId CudbAppServiceId=1 } When I dump it in XML format, I got the following: <?xml version="1.0" encoding="utf-8"?> <CudbAppServiceId=1> <userLabel/> <sqlAppSrvPlSchema>identities-pl.sql</sqlAppSrvPlSchema> <CudbAppServiceId>CudbAppServiceId=1</CudbAppServiceId> </CudbAppServiceId=1> This is not a valid XML, because we have a tag "CudbAppServiceId=1". Of course, any other xml parser like xmllint will fail to parse it, because of the equality sign in the tag. Is there any solution to this problem? Like somehow emitting = instead of the raw '=' inside the tag and in the text? Thanks, Gabor

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chaining functions input output
by MM 19 Feb '13

19 Feb '13

Hello, i have these 2 functions provided to me and I wonder whether they can somehow be chained without using intermediary memory? http://codepad.org/tTwkUQhp Rds, MM

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[Lockfree] Interprocess Support
by Gábor Márton 19 Feb '13

19 Feb '13

Hi, In 1.53 documentation it is said: The boost.lockfree data structures have basic support for Boost.Interprocess. The only problem is the blocking emulation of lock-free atomics, which in the current implementation is not guaranteed to be interprocess-safe. What does that and interprocess-safety exactly mean? Is it possible to use an interprocess allocator (e.g. allocator<int, managed_shared_memory::segment_manager>) together with lockfree::queue? Or shall I expect unexpected behaviour? Thanks, Gabor

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Thread safety in Boost msm
by Ukil, Soumya P 18 Feb '13

18 Feb '13

Hi, I am new to boost meta state library. I am building one app, where I have to use msm. My application has two threads, where they use same msm object as a shared resources. Now will the msm be thread safe if both threads call process_event on the same msm object? Any idea is welcome. Thanks, Soumya P. Ukil Morgan Stanley | ISG Technology Building #5. Sector 30 | Mindspace, Goregaon (West) Mumbai (Ex Bombay), 400 090 Phone: +91 22 6641-0038 Soumya.Ukil(a)morganstanley.com<mailto:Soumya.Ukil@morganstanley.com> Be carbon conscious. Please consider our environment before printing this email. ________________________________ NOTICE: Morgan Stanley is not acting as a municipal advisor and the opinions or views contained herein are not intended to be, and do not constitute, advice within the meaning of Section 975 of the Dodd-Frank Wall Street Reform and Consumer Protection Act. If you have received this communication in error, please destroy all electronic and paper copies and notify the sender immediately. Mistransmission is not intended to waive confidentiality or privilege. Morgan Stanley reserves the right, to the extent permitted under applicable law, to monitor electronic communications. This message is subject to terms available at the following link: http://www.morganstanley.com/disclaimers If you cannot access these links, please notify us by reply message and we will send the contents to you. By messaging with Morgan Stanley you consent to the foregoing.

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[Boost.Coroutine] sample in docs
by Lukas Czaja 18 Feb '13

18 Feb '13

Hi, i would like to ask about sample in docs http://www.boost.org/doc/libs/1_53_0/libs/coroutine/doc/html/coroutine/intr… what if several threads run asio::io_service::run(), so is it safe to resume execution state in CompletionHandler in diffrent thread from when execution state was saved ? And what will happen if io_service completes before saving contex (look code below)? s_.async_read_some( boost::asio::buffer( buffer_ + pb_size, bf_size - pb_size), boost::bind( & coro_t::operator(), & coro_, _1, _2) ); // Q: what will happen if handler completes here, before contex switch ca_();

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