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odeint feedback request
by Karsten Ahnert 23 Oct '11

23 Oct '11

Dear community, odeint is a library for solving ordinary differential equations and has been discussed several times on this list. After successfully fulfilling the GSOC 2011 we continued working on odeint and we published two papers which are available at the arxiv: http://arxiv.org/abs/1110.3397 http://arxiv.org/abs/1110.3233 We would like to request feedback and/or comments on the implementation and the current status of odeint. The library and the documentation are available at the github: https://github.com/headmyshoulder/odeint-v2 http://headmyshoulder.github.com/odeint-v2/doc/index.html Thank you, Mario and Karsten

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[atomic] Initial comments
by Grund, Holger 23 Oct '11

23 Oct '11

Hi everyone, It's been awfully quiet on the list regarding the atomic review. The atomic operations library is an invaluable tool for higher level concurrent data structures and algorithms. While toolchain vendors have already or starting to support <atomic>, many people are stuck on compiler where there is currently no support at all. Building these libraries yourself is tedious and prone to error and errors that are hard to spot. I am in this situation and therefore very much appreciate Helge's effort and think the lack of review comments so far should not be taken as a lack of interest. Now, I haven't had the time to look on things in any detail yet. I ignored the docs (~~) and only locked at the atomic header and some of x86 implementation so far. I haven't tried to build anything, but I intend to do a proper review though it's unlikely I'll manage to get to it on the official time line. I would have put some of the comments of the review tool site, but I can't login right now: - The fallback atomic_thread|signal_fence in boost/atomic.hpp seem to have external linkage, but no inline. Doesn't that give a ODR violation when included from more than on TU? - The copy-assignment operators seem to always return atomic&. IIRC, the earlier working drafts said return value_type. Has this changed? - The primary base_atomic is not aligned at all, AFAICT. I take it because you explicit need to extract bits anyhow and that means a memcpy. Does this have a performance impact? - Inline asm is the preferred way to build instructions. Did you consider intrinsics where available (e.g. ICC and GCC4+)? - atomic_flag is not statically initialized: I guess, there is some tradeoff with uniform-initialization syntax and member functions on most (all?) current production compilers. However, it seems to me that static initialization guarantees are atomic_flag's primary if not sole raison d'etre. Did you consider to make it a statically initializable type? - What's the point of the fences around cmpxchg in x86? - I'm not a GNU inline assembly expert and it's probably fairly unlikely to really affect codegen, but shouldn't clobbered flags be mentioned? Also the EBX handling for 32-bit Linux code may deserve some additional comment. I take it you can't mention ebx in the clobber list because the register allocator would complain for -fPIC, right? Does the impact unwinding? - I seem some of the *LOCK_FREE macros are defined involving sizeof. I've always assumed these macros (or the corresponding standard ones) would be suitable for use in #if processing. Wouldn't that be one of the main use cases? Thanks! -hg Holger Grund, Vice President Morgan Stanley | Cross-Technology Services 25 Cabot Square | Canary Wharf | Floor 03 London, E14 4QA Phone: +44 20 7677-4095 Holger.Grund(a)morganstanley.com -------------------------------------------------------------------------- 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 threads] threadid copy constructor
by Jason Newton 21 Oct '11

21 Oct '11

The following patch adds a copy constructor to threadid. There seems to be no reason why they shouldn't be copyable. Comments? -Jason

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difference_type size()?
by Olaf van der Spek 21 Oct '11

21 Oct '11

Hi, iterator_range returns a signed size. Is this correct? IMO it should return size_t. boost\range\iterator_range_core.hpp: difference_type size() const { return m_End - m_Begin; } Olaf

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Using trac for boost-sandbox?
by Paul A. Bristow 21 Oct '11

21 Oct '11

Is it permitted to use the Boost Trac system for libraries under development at boost-sandbox? This would be very helpful. (especially if a history could refer to the Trac in Quickbook, as done in Boost.Pool new docs at pool.qbk [section:tickets Appendix E: Tickets] Report and view bugs and features by adding a ticket at [@https://svn.boost.org/trac/boost Boost.Trac]. Existing open tickets for this library alone can be viewed [@https://svn.boost.org/trac/boost/query?status=assigned&status=new&status=reopened&component=pool&c ol=id&col=summary&col=status&col=owner&col=type&col=milestone&order=priority here]. Existing tickets for this library - including closed ones - can be viewed [@https://svn.boost.org/trac/boost/query?status=assigned&status=closed&status=new&status=reopened&co mponent=pool&col=id&col=summary&col=status&col=owner&col=type&col=milestone&order=priority here]. [endsect] [/section:tickets Appendix E: Tickets] This removes a boring burden on authors on updating the history of features and bugs. (There isn't an option to use sandbox in the drop-downs - only trunk, release, 1.n ...). Paul --- Paul A. Bristow, Prizet Farmhouse, Kendal LA8 8AB UK +44 1539 561830 07714330204 pbristow(a)hetp.u-net.com

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Fwd: Re: [Boost-announce] [Review] Boost.Atomic review starts today, October 17th 2011
by Tim Blechmann 21 Oct '11

21 Oct '11

---------- Forwarded Message ---------- Subject: Re: [Boost-announce] [boost] [Review] Boost.Atomic review starts today, October 17th 2011 Date: Friday 21 October 2011, 10:20:42 From: Darren Cook <snip> CC: Tim Blechmann <tim(a)klingt.org> > Boost.Atomic ... implements the > interface as defined by the C++11 standard, but makes this feature available > for platforms lacking system/compiler support for this particular C++11 > feature. Hello, (I wanted to cc Helge Bahmann but couldn't find an email address) As the library is a stand-in until compilers catch-up, I think it would be useful to have a page in the documentation that shows the minimum compiler versions where it is no longer needed, for at least the major compilers. (I skimmed the docs but couldn't see this covered.) Darren P.S. No need to reply, and sorry I won't be able to take part in the review. (I'm also not on boost-devel list currently.)

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Throws exception while deserializing large no object
by Bikas Tanti 21 Oct '11

21 Oct '11

I'm using vs 2010 and getting memory leaks when deserializing objects with binary archive . #include <boost/archive/binary_oarchive.hpp> #include <boost/archive/binary_iarchive.hpp> class ElementResultData { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar,const unsigned int version) { ar & m_pass; ar & m_fail; ar & m_units; ar & m_result_no; ar & m_outof_tolerance; ar & m_iPartNo; ar & m_iActualValue; ar & m_iMeasurement1; ar & m_iMeasurement2; ar & m_iMeasurement3; } public: std::string m_pass; std::string m_fail; std::string m_units; std::string m_result_no; std::string m_outof_tolerance; unsigned long m_iPartNo; double m_iActualValue; double m_iMeasurement1; double m_iMeasurement2; double m_iMeasurement3; public: ElementResultData(){}; ElementResultData(std::string ps,std::string fl,std::string unit,std::string rno,std::string tol, int n,double av,double m1,double m2, double m3) : m_pass(ps),m_fail(fl),m_units(unit),m_result_no(rno),m_outof_tolerance(tol),m_iPartNo(n), m_iActualValue(av),m_iMeasurement1(m1),m_iMeasurement2(m2),m_iMeasurement3(m3) {} }; //DataResultDlg.h class CDataResultDlg { // Construction public: std::map<int, ElementResultData> m_mElemResDatafirst; std::map<int, ElementResultData> m_mElemResDataSecond; std::map<int, ElementResultData> m_mElemResultData; }; //DataResultDlg.cpp #define NUM_ELEMENTS 50000 // works fine when NUM_ELEMENTS is 1 class CDataResultDlg { for(unsigned long i=0;i<NUM_ELEMENTS;i=i+2) { m_mElemResDatafirst.insert(std::make_pair(i, ElementResultData("Pass","No", "MM","PartA","O",i,1.6020,1.0400,1.320,1.1010))); m_mElemResDatafirst.insert(std::make_pair(i+1,ElementResultData("Fail","Yes","MM","PartB","O",i+1,1.085,1.0004,2.320,1.1010))); } //Saving Data std::ofstream ofs("ResultData"); // save data to archive { boost::archive::binary_oarchive oafirst(ofs,std::ios::app); //write instance to archive int no_of_map = 2; oafirst<< no_of_map; oafirst << m_mElemResDatafirst; oafirst << m_mElemResDataSecond; } //Loading Data std::ifstream ifs("ResultData",std::ios::binary); { // create and open an archive for input boost::archive::binary_iarchive ia(ifs); // read class state from archive int no_of_Element; ia>>no_of_Element; for(int i =0;i<no_of_Element;i++) ia >>m_mElemResultData; *// Out Of Memory * }; Same code works fine for text_archive.I have to serialize huge amount of data to a file . Any help will be appreciated . -- View this message in context: http://boost.2283326.n4.nabble.com/Throws-exception-while-deserializing-lar… Sent from the Boost - Dev mailing list archive at Nabble.com.

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[msm] state machine construction / destruction
by Jinsong Huang 21 Oct '11

21 Oct '11

MSM enthusiasts, I have done a performance profiling with a simple parser with 3 implementations, plain C++, SMC and Boost MSM. I was happy to learn that the MSM implementation was very efficient. I'm having some questions about MSM space allocation, please let me know if my understanding of things are wrong (very likely). I work in a high performance computing environment so I will try to minimize unnecessary object constructions. Is it possible for the data in the state machine backend live somewhere else external to the state machine? If that's possible then I can put the state machine's internal states close to the data that needs to be manipulated and the state machine itself is data-less and I can have a single copy of the state machine and each data item carries everything. I know this breaks encapsulation but I'm just wondering. The state machine has a events queue (std::deque?), can I choose to not have this and other data structures I don't think I will need? Thanks, -jh

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enable_if : how to make it work in the case of templated method of a template base inherited several times
by nico 20 Oct '11

20 Oct '11

I hope the subject didn't make you run away ;-) Let me be clearer (I'll try at least): If I have a template base class with a template method : template <typename T> class S { public: template <typename U> void f(U p, typename enable_if<is_same<T, U> >::type*dummy = 0) { std::cout << p << std::endl; } }; For the example, I simplify the method : it must "exists" only if T == U If A is this class: class A : public S<int> {}; Then I have what I want: int i = 1; A a; a.f(i); compiles, but double d = 2.0; a.f(d); doesn't compile : error: no matching function for call to ‘A::f(double&)’ It is the expected behavior. Now let's A inherit from S<double> also : class A : public S<int>, public S<double> {}; Then the following code doesn't compile : int i = 1; A a; a.f(i); error: request for member ‘f’ is ambiguous error: candidates are: template<class U> void S::f(U, typename boost::enable_if<boost::is_same<T, U>, void>::type*) [with U = U, T = double] error: template<class U> void S::f(U, typename boost::enable_if<boost::is_same<T, U>, void>::type*) [with U = U, T = int] I expected there is no ambiguity : f<int> exists only for S<int> In the compiler error, we can notice that T is known when this piece of code is compiled, but not U (U = U). Any explanation or "workaround" ? Thanks. Nicolas.

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[Re:Opaque Typedef] observations on opaque typedef
by Robert Ramey 20 Oct '11

20 Oct '11

Vicent - I saw your post on this subject some months ago and I've reviewed the thread. I didn't look at the code though. I also looked at the C++0x document and I have something to say about this. a) as you know I'm the author of BOOST_STRONG_TYPEDEF which lets one assign a unique type to some primitive integer type. I did this to permit overloads on integers used for different purposes. The new types created had all the properties of integer types but they were all different types. So far so good. b) I eventually found the BOOST_STRONG_TYPEDEF did too much - what I really wanted to not to inherit all the interoperations but only some of them. So I've reduced or eliminated usage of BOOST_STRONG_TYPE from the serialization library implementation. Never the less, I do see it useful in other contexts so your efforts to create and opaque typedef seem useful to me. c) BUT now I really want something else. I want the ability to assign a new type to an existing type. The current typedef has the feature that if two different names are used for the same type, a new type is NOT created. That is typedef creates a synonym rather than a new type. I thought that C++0x template alias would do this. But a careful reading of the standard document that I have leads me to believe that if two names are aliased to the same underlying type - a new type is not created - just like the current typedef. So what we have in the new C++ is basically a templated typedef. d) what I really need is the equivalent to #define OPAQUE_TYPEDEF(name, t) \ struct name : public t {}; so I can say struct dollar_amount { ... operator *(const & rhs) const {..} // don't include this operator - makes no sense }; OPAQUE_TYPEDEF(debit, dollar_amount); OPAQUE_TYPEDEF(price, dollar_amount) and then say void f(debit, t){...} void f(price t){...} Notice in my example, I don't want debit and price types to be true types and not just synonyms for dollar_amount. I realize that this is whole different kettle of fixh than BOOST_STRONG_TYPE or OPAQUE_TYPE. So this might be considered off topic. or maybe not. Comments welcome. Also anyone can feel free to correct my understanding of the template alias feature of C++0x to create new types. Robert Ramey

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